United StatesDepartment ofAgriculture

Forest Service Northeastern Area State & Private Forestry

Natural Resources Conservation Service

Cooperative State Research, Education, and Extension Service

NA-TP-02-97

Chesapeake BayRiparian Handbook:

A Guide for Establishingand Maintaining RiparianForest Buffers

####################CHESAPEAKE BAY NORTHEASTERN AREA PROGRAM State and Private Forestry

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Edited by:

Roxane S. PaloneWatershed SpecialistUSDA Forest Service

Northeastern Area - State and Private ForestryMorgantown, WV

and

Albert H. ToddChesapeake Bay Program Liaison

USDA Forest ServiceNortheastern Area - State and Private Forestry

Annapolis, MD

May 1997Revised June 1998

HYDROLOGIC UN IT MAP OF THE

CHESAPEAKE BAY WATERSHED DEL. !P.iC .• MD •• N.Y., PA.. VA.

AND W.V,

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Acknowledgments

Managing Editor: Nancy A. Lough, Visual Information SpecialistAssistant Managing Editors: Brenda L. Wilkins, Technology Transfer Specialist

Kasey L. Russell, Information AssistantProduction Assistant: Helen A. Wassick, Office Automation Clerk

Contributing Authors:

Richard A. Cooksey; USDA Forest Service; Annapolis, MD

J. Michael Foreman; Virginia Department of Forestry; Charlottesville, VA

Steven W. Koehn; Maryland Forest; Wildlife; and Heritage Service; Annapolis, MD

Brian M. LeCouteur; Metropolitan Washington Council of Governments; Washington, DC

Richard Lowrance; USDA Agricultural Research Service; Tifton, GA

William Lucas; Integrated Land Management; Malvern, PA

Nancy A. Myers; USDA Forest Service; Carefree, AZ

Roxane S. Palone; USDA Forest Service; Morgantown, WV

James L. Robinson; USDA Natural Resources Conservation Service; Ft. Worth, TX

Gordon Stuart; USDA Forest Service (retired); Morgantown, WV

Karen J. Sykes; USDA Forest Service; Morgantown, WV

Robert Tjaden; University of Maryland Cooperative Extension Service; Queenstown, MD

Albert H. Todd; USDA Forest Service; Annapolis, MD

We extend a hearty “thank you” to the following for making this publication possible. We appreciate allyour comments, hard work, and suggestions.

Warren Archey, State Forester, Commonwealth of Massachusetts; John Barber, Chair,Forestry Workgroup, Nutrient Subcommittee, Chesapeake Bay Program; Karl Blankenshipand Brook Lenker, Alliance for the Chesapeake Bay; Earl Bradley, Maryland Departmentof Natural Resources; Dan Greig, Chester County Conservation District; Bill Brumbley,Wayne Merkel, and David Plummer, Maryland Forest, Wildlife, and Heritage Service;Patty Dougherty, Jim Hornbeck, Dan Kucera, Jim Lockyer, and Arlyn Perkey, USDAForest Service; Patricia Engler, Natural Resources Conservation Service; Claudia Jones,Chesapeake Bay Critical Area Commission; Jerry Martin, Pequea-Mill Creek Project;Robert Merrill, Pennsylvania Bureau of Forestry; Mark Metzler, Lancaster CountyConservation District; Joe Osman, Pennsylvania Game Commission; Erin Smith; andRobert Whipkey, West Virginia Division of Forestry

If you find this publication helpful, please write and tell us how you used it.

Information ServicesForest Resources Management

USDA Forest ServiceNortheastern Area-State & Private Forestry

180 Canfield StreetMorgantown, WV 26505

Palone, R.S. and A.H. Todd (editors.) 1997. Chesapeake Bay riparian handbook: a guide forestablishing and maintaining riparian forest buffers. USDA Forest Service. NA-TP-02-97.Radnor, PA.

The use of trade, firm, or corporation names in this publication is for the information andconvenience of the reader. Such use does not constitute an official endorsement or approval of anyproduct or services by the U.S. Department of Agriculture to the exclusion of others which may besuitable.

Information about pesticides appears in the publication. Publication of this information does notconstitute endorsement or recommendation by the U.S. Department of Agriculture, nor does it implythat all uses discussed have been registered. Use of most pesticides is regulated by State andFederal law. Applicable regulations must be obtained from appropriate regulatory agencies.

CAUTION: Pesticides can be injurious to humans, domestic animals, desirable plants, and fish orother wildlife if not handled or applied properly. Use all pesticides selectively and carefully. Followrecommended practices given on the label for use and disposal of pesticides and pesticidecontainers.

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To file a complaint, write the Secretary, U.S. Department of Agriculture, Washington, DC 20250 orcall 1-800-245-6340 (voice) or 202-720-1127 (TDD). USDA is an equal employment opportunityemployer.

TABLE OF CONTENTS

I. IntroductionThe Purpose of This Handbook............................................................................1-1Historical Background..........................................................................................1-1Defining the Chesapeake Bay’s Riparian Resources ...........................................1-2Describing Riparian Forest Buffers in Different Landscapes ..............................1-5The Three Zone Concept:

A Tool to Guide Forest Buffer Planning.......................................................1-8Additional Definitions........................................................................................1-10References ..........................................................................................................1-14

II. Physiographic and Hydro-Physiographic ProvincesIntroduction ..........................................................................................................2-1Northern Glaciated Allegheny Plateau.................................................................2-4Northern Ridge and Valle ...................................................................................2-5Northern Appalachian Piedmont..........................................................................2-6Southern Appalachian Piedmont..........................................................................2-7Middle Atlantic Coastal Plain ..............................................................................2-8Hydro-Physiographic Response ...........................................................................2-9Major Hydro-Physiographic Regions in the Chesapeake Watershed.................2-10References ..........................................................................................................2-18

III. Functions/Values of Riparian Forest BuffersIntroduction ..........................................................................................................3-1WATER QUALITY AND HYDROLOGIC FUNCTIONS/VALUES OF

RIPARIAN FOREST BUFFER SYSTEMS.................................................3-1How Riparian Forest Buffers Control the Stream Environment ..........................3-3How Riparian Forest Buffers Facilitate Removal of

Nonpoint Source Pollutants ..........................................................................3-6Integrated Water Quality Functions of Riparian Forest Buffer Systems............3-11Loading Rates and Nonpoint Source Pollution Control.....................................3-11Stream Order and Size Effects ...........................................................................3-12Stormwater Management ...................................................................................3-13Flood Reduction and Control .............................................................................3-13WILDLIFE AND FISH HABITAT FUNCTIONS/VALUES OF

RIPARIAN FOREST BUFFER SYSTEMS...............................................3-14Riparian Area Importance to Wildlife................................................................3-15Principles of the Riparian Ecosystem.................................................................3-16Structure .............................................................................................................3-17Travel Corridors .................................................................................................3-25Fish Habitat ........................................................................................................3-26Management Considerations ..............................................................................3-29AESTHETICS AND OUTDOOR RECREATION FUNCTIONS/VALUES

OF RIPARIAN FOREST BUFFER SYSTEMS.........................................3-34Types of Recreation That Occur in Riparian Forests .........................................3-35

References ..........................................................................................................3-38

IV. SoilsIntroduction ..........................................................................................................4-1Definitions............................................................................................................4-1Factors of Soil Formation.....................................................................................4-1Soil Classification ................................................................................................4-5Soil Characteristics...............................................................................................4-6Soil Characteristics Relating to Hydrolog ........................................................4-11Information Necessary to Establish Riparian Forest Buffers .............................4-14The Soil Survey..................................................................................................4-14Hydrologic Soil Groups......................................................................................4-18Land Capability Classification ...........................................................................4-19Soil as It Relates to Establishing a Riparian Forest Buffer ................................4-20References ..........................................................................................................4-22

V. Design of Buffer Systems for Nonpoint Source Pollution ReductionIntroduction ..........................................................................................................5-1Suspended Sediments and Sediment Bound Pollutants .......................................5-1Nitrates and Dissolved Pesticides ........................................................................5-6References ..........................................................................................................5-12

VI. Determining Buffer WidthDetermining the Width of Riparian Buffers.........................................................6-1Buffer Width Criteria ...........................................................................................6-1Science-Based Criteria .........................................................................................6-2Landowner-Based Criteria..................................................................................6-11Application.........................................................................................................6-11Fixed Minimum Versus Variable Width Buffers...............................................6-12Conclusion..........................................................................................................6-13References ..........................................................................................................6-14

VII. Site Evaluation, Planning, and EstablishmentRIPARIAN SITE EVALUATION AND PLANNING ........................................7-1Site Analysis - Physical Features .........................................................................7-1Site Analysis - Vegetative Features .....................................................................7-7RIPARIAN FOREST BUFFER ESTABLISHMENT........................................7-11Site Preparation ..................................................................................................7-12Riparian Forest Buffer Design ...........................................................................7-16Riparian Forest Buffer Planting .........................................................................7-24RIPARIAN FOREST BUFFER MAINTENANCE...........................................7-33References ..........................................................................................................7-34

VIII. Streamside Stabilization as a Component of Riparian RestorationIntroduction ..........................................................................................................8-1Stabilization Techniques ......................................................................................8-1Planning for Streambank and Channel Restoration .............................................8-4

Construction Techniques and Materials...............................................................8-5Tree Revetments...................................................................................................8-5Live Stakes .........................................................................................................8-10Live Fascines......................................................................................................8-12Brushlayer ..........................................................................................................8-13Branchpacking....................................................................................................8-15Live Cribwall......................................................................................................8-17Lunker Structures ...............................................................................................8-18Other Innovative Methods..................................................................................8-20Guides and Manuals for Streambank Stabilization............................................8-21

IX. Agricultural/Rural AspectsIntroduction ..........................................................................................................9-1The Stream System...............................................................................................9-2Cropland...............................................................................................................9-3Riparian Buffer Design for Cropland...................................................................9-4Pastureland ...........................................................................................................9-4Livestock Confinement or Concentration Areas ..................................................9-6Farm Woodlots or Forest......................................................................................9-7Putting It All Together .........................................................................................9-7Plan Implementation and Riparian Forest Buffers ...............................................9-7Examples of How Riparian Forest Buffers Can Be Integrated into

Farm Streamside Management Systems .......................................................9-8 Example 1. Crop Production Farm .........................................................9-8 Example 2. Beef Cattle Operation ........................................................9-10 Example 3. Dairy Farm.........................................................................9-11

Planning and Application Assistance.................................................................9-13References ..........................................................................................................9-13

X. Silvicultural/Forest Management AspectsIntroduction….. ..................................................................................................10-1Factors Influencing Forest Resources Management...........................................10-1Landowner Types and Their Objectives in Riparian Management....................10-3Summary and Review of Silvicultural Systems.................................................10-4Managing the Riparian Forest Buffer...............................................................10-13Example Prescriptions......................................................................................10-14Forest Resources Protection.............................................................................10-14References ........................................................................................................10-24

XI. Urban/Suburban AspectsIntroduction ........................................................................................................11-1Buffer Specification Guidance ...........................................................................11-6Planning Reforestation Sites in Urban Areas...................................................11-15Ordinances/Zoning...........................................................................................11-25Implementing a Riparian Reforestation Plan ...................................................11-27References ........................................................................................................11-33

XII. Economics of Riparian Forest BuffersIntroduction ........................................................................................................12-1Economic Value .................................................................................................12-1Economic Benefits Associated with Riparian Forest Buffers ............................12-2Costs Associated with Riparian Forest Buffers..................................................12-7Economic Impacts of Riparian Forest Buffers ...................................................12-9Scenario #1: Agricultural Field .......................................................................12-10Scenario #2: Forest Site...................................................................................12-13Scenario #3: Subdivision Development Site...................................................12-16Comparison of Trees, Row Crops, and Pasture on Land with Class IIIe

Capabilit ..................................................................................................12-19Finance Tools and Economic Incentives..........................................................12-20References ........................................................................................................12-23

XIII. Information and Education StrategiesIntroduction ........................................................................................................13-1Natural Resource Professional Training.............................................................13-1Landowner Information and Education..............................................................13-2Working with Volunteers ...................................................................................13-6Working with the Media ....................................................................................13-6Information Resources .......................................................................................13-7References ..........................................................................................................13-9

XIV. Appendices

1. USDA Forest Service Specification-Riparian Forest Buffer ..................................14-12. Natural Resources Conservation Service

Conservation Practice Standard Riparian Forest Buffer .................................14-23. USDA Natural Resources Conservation Service

Maryland Conservation Practice Standard Riparian Forest Buffer.................14-34. Program Contacts in the Chesapeake Bay Watershed ............................................14-45. Bay Area Riparian Forest Buffer-Related Programs ..............................................14-56. Excerpts from the Chesapeake Bay Riparian Forest Buffer Inventor ...................14-67. Native Plant Guide for Planting Along Streams and Ponds ...................................14-78. Sources of Planting Stock.......................................................................................14-89. USDA Plant Hardiness Zone Map..........................................................................14-9

10. Sources of Tree Shelters .......................................................................................14-1011. Companies that Provide Materials and Services in the Areas of Streambank

Stabilization, Erosion and Sediment Control, and Geotextiles .....................14-1112. Herbicide Labels ...................................................................................................14-12

Section III

Functions/Values of Riparian Forest Buffers

Introduction ..........................................................................................................3-1WATER QUALITY A ND HYDROLOG IC FUNCTIONS/VALUES OF

RIPARIAN FOREST BUFFER SYSTEMS .............................................3-1How Riparian Forest Buffers Control the Stream Environment ..........................3-3How Riparian Forest Buffers Facilitate Removal of

Nonpoint Source Pollutants ..........................................................................3-6Integrated Water Quality Functions of Riparian Forest Buffer Systems............3-11Loading Rates and Nonpoint Source Pollution Control.....................................3-11Stream Order and Size Effects ...........................................................................3-12Stormwater Management ...................................................................................3-13Flood Reduction and Control .............................................................................3-13WILDLIFE AND FISH HABITAT FUNCTIONS/VALU ES O

RIPARIAN FOREST BUFFER SYSTEMS ...........................................3-14Riparian Area Importance to Wildlife................................................................3-15Principles of the Riparian Ecosystem.................................................................3-16Structure .............................................................................................................3-17Travel Corridors .................................................................................................3-25Fish Habitat ........................................................................................................3-26Management Considerations ..............................................................................3-29AESTHETICS AND OUTDOOR RECREATION FUNCTIONS/VALUES

OF RIPARIAN FOREST BUFFER SYSTEMS.....................................3-34Types of Recreation that Occur in Riparian Forests ..........................................3-35References ..........................................................................................................3-38

Section III

3-1

IntroductionThis section describes the functions and valuesof riparian areas and riparian forest buffers asthey relate to:

• Water Quality and Hydrology

• Wildlife and Fish

• Aesthetics and Outdoor Recreation

Water Quality and HydrologicFunctions/Values of Riparian

Forest Buffer Systems

First and second order streams comprise nearlythree-quarters of the total stream length in theUnited States (see Figure 3-1). Riparian eco-systems along these small streams areinfluenced by processes occurring on both landand water. Small streams can be completelycovered by the canopies of streamside vegeta-tion. Riparian vegetation has well-knownbeneficial effects on the bank stability, biologi-cal diversity, and water temperatures of streams.Riparian forests of mature trees (30 to 75 yearsold) are known to effectively reduce nonpointpollution from agricultural fields.

Compared to other water quality improvementmeasures, Riparian Forest Buffer Systems(RFBS) can lead to longer-term changes in thestructure and function of human-dominatedlandscapes. To produce long-term improve-ments in water quality, RFBS must be designedwith an understanding of the following:

• processes which remove or sequester pollut-ants entering the riparian buffer system

• effects of riparian management practices onpollutant retention

• effects of riparian forest buffers on aquaticecosystems

• effects and potential benefits of planned har-vesting of trees on riparian buffer systems

• effects of underlying soil and geologic mate-rials on chemical, hydrological, andbiological processes

It is important to note that the current under-standing of the functions of the RFBS is basedon studies that have been done in areas whereriparian forests currently exist because of acombination of hydrology, soils, cultural prac-tices, and economics. Most of the currentknowledge of the water quality functions of thethree zones of the RFBS specification is derivedfrom studies in existing riparian forests and onexperimental and real-world grass buffer sys-tems.

Functions/Values of Riparian Forest Buffers

Section III

3-2

Figure 3 - 1. Stream orders as illustrated in the Alliance for the Chesapeake Bay White Paper, 1996.

Section III

3-3

How Riparian Forest BuffersControl the Stream EnvironmentAlthough reduction of nonpoint source (NPS)pollution is a widely recognized function ofriparian forest buffer systems, they also contrib-ute significantly to other aspects of waterquality and physical habitat. Habitat alterations,especially channel straightening and removal ofriparian vegetation, continue to impair the eco-logical health of streams more often and forlonger time periods than toxic chemicals.Studies in Pennsylvania consider loss of riparianforests in eastern North America to be one ofthe major causes of aquatic ecosystem degrada-tion.

Zone 1, the permanent woody vegetation at thestream edge, enhances ecosystem stability andhelps control the physical, chemical, and trophicstatus of the stream. Healthy riparian vegetationin Zone 1 also contributes to bank stability andminimizes instream sediment loading because ofbank erosion. Zone 1 also has substantial abilityto control NPS pollution through denitrification,sedimentation, or direct root uptake of pollut-ants.

Riparian forest vegetation controls light quantityand quality, moderates temperature, stabilizeschannel geometry, provides tree roots andwoody debris for habitat, and provides litter fordetritivores. To maintain the biological integ-rity of the aquatic ecosystem, an ideal managedbuffer system should have patterns of vegeta-tion, litterfall, and light penetration similar tothose in a natural, undisturbed riparian forest.However, for many locations, representativesites of truly natural, undisturbed riparian eco-systems do not exist. In fact, after a long historyof human disturbance in many areas, the conceptcan be difficult to define. Studies suggest thatwithin a homogeneous region, relatively pristineareas may be identified as benchmarks for theevaluation of other sites.

1. Temperature and LightThe daily and seasonal patterns of water tem-perature are critical habitat features that directlyand indirectly affect the ability of a given streamto maintain viable populations of most aquaticspecies, both plant and animal. Considerableindirect evidence suggests that the absence ofriparian forests along many streams and rivers inthe Chesapeake drainage, particularly in agri-cultural areas, may have a profound effect onthe current geographic distribution of many spe-cies of macroinvertebrates and fish. Studiesreviewed the effects of temperature alterationson the growth, development, and survival ofstream macroinvertebrates found in the Penn-sylvania Piedmont. These studies showed thattemperature changes of 2-6° C usually alter keylife-history characteristics of most of the studyspecies.

In the absence of shading by a forest canopy,direct sunlight can warm stream temperaturessignificantly, especially during summer periodsof low flow. For example, maximum summertemperatures have been reported to increase 6°-15° C following removal of the riparian forestcanopy. Streams flowing through forests willwarm very rapidly as they enter deforested ar-eas, but excess heat dissipates quickly whenstreams reenter the forest. Studies demonstratedthis alternate warming (by 4-5° C) and coolingas a stream passed through clearcut and uncutstrips in the Hubbard Brook Experimental For-est, New Hampshire. In Pennsylvania (Ridgeand Valley Province), average daily stream tem-peratures that increased 11.7° C through aclearcut area were substantially moderated afterflow through 500 meters of forest below theclearcut. The temperature reduction was attrib-uted primarily to inflows of cooler groundwater.The impact of deforestation on stream tempera-ture varies seasonally. In the PennsylvaniaPiedmont, studies found that from April throughOctober average daily temperatures in a sec-ond-order meadow stream reach were higherthan in a comparable wooded reach, but that thereverse was true from November throughMarch.

Section III

3-4

Riparian forest buffers have been shown to pre-vent the disruption of natural temperaturepatterns as well as to mitigate the increases intemperature following deforestation. Studiesfound that buffer strips of 10 meters wide wereas effective as a complete forest canopy in re-ducing solar radiation reaching small streams inthe Pacific Northwest. The exact width of Zone1 needed for temperature control will vary fromsite-to-site depending on a variety of factors (seeSections V and VI). A previous study pointedout that: 1) streams oriented in a north-southdirection are less easily shaded than streamsflowing east or west, and 2) a buffer on thenorth side of a stream may have little or no ef-fect. Also, in larger streams and rivers, thewidth of the channel prevents a complete can-opy cover, so the effect of canopy shading maybe reduced. In eastern North America, openingsin the canopy immediately above streams occurwhen the channel width exceeds about 20 me-ters in width (i.e., about stream order 4 or 5).Stream orientation relative to solar angle mayalso affect the extent of shading for largerstreams. Although shading on larger rivers mayhave little or no influence on water temperature,shaded stream banks provide habitat micrositesfor fish and other aquatic organisms.

The ability of a given width of streamside forestto maintain or restore the natural temperaturecharacteristics of a stream segment depends onhow it affects the factors that control the dailyand seasonal thermal regime of the stream.Such factors (other than shading) include: flow,channel geometry, solar radiation, evaporativeheat loss, conductive surface heat exchange,and, in some cases, conductive heat exchangewith the streambed.

2. Habitat Diversity and ChannelMorphologyThe biological diversity of streams depends onthe diversity of habitats available. Woody de-bris is one of the major factors in habitatdiversity. Woody debris can benefit a streamby:

• stabilizing the stream environment by re-ducing the severity of the erosive influenceof stream flow,

• increasing the diversity and amount of habi-tat for aquatic organisms,

• providing a source of slowly decomposablenutrients, and

• forming debris dams, it enhances the avail-ability of nutrients for aquatic organismsfrom more rapidly decaying material.

Quantities of large woody debris (LWD) rec-ommended for healthy streams in the GeorgeWashington National Forest in Virginia rangefrom 34 pieces of LWD per km for warm waterfisheries to 136 pieces/km for cold water fish-eries. Although the quantity of woody debris instreams without forested riparian areas would beexpected to be very low, there are few quantita-tive studies. Studies in Pennsylvania found thatthe volume of woody debris under forestedcanopies in a Mid-Atlantic Piedmont stream was20 times greater than the volume in a compara-ble meadow reach. Following removal of ariparian forest, large woody debris present in thestream declines through gradual decomposition,flushing during storms, and lack of inputs.Smaller debris from second-growth stands pro-motes less stability of the aquatic habitat andtends to have a shorter residence time in thestream.

Loss of streamside forest can lead to loss ofhabitat through stream widening where no per-manent vegetation replaces forest, or throughstream narrowing where forest is replaced bypermanent sod. In the absence of other peren-nial vegetation, bank erosion and channelstraightening can occur as unimpeded stream-flow scours the streambed and banks. Theaccelerated streamflow velocity allowed bystraight channels promotes channel incision aserosion from the stream bottom exceeds sedi-ment entering the stream. This process caneventually lead to the development of wide,shallow streams that support fewer species.

Section III

3-5

Studies point out that stability of debris accu-mulation is important for aquatic habitat.Because of the greater resistance to displace-ment by hydraulic forces, large woody debris isof greater benefit to stream stability. Longermaterial is relatively more important for the sta-bility of wider streams.

In contrast, narrowing of stream channels hasalso been reported following the replacement ofstreamside forest with permanent grassland orgrass sod. Studies found that the narrowing ofdeforested stream channels was evident forstreams up to drainage areas five square miles,or about a third or fourth order stream. Otherstudies quantified the narrowing phenomenonmore explicitly in a Pennsylvania Piedmont ba-sin, showing that:

• first and second order wooded reaches aver-aged about 2 times wider than their meadowcounterparts of the same order.

• third and fourth order forested reaches wereabout 1.7 times wider than in deforestedareas.

The channel narrows in the absence of a stream-side forest because grassy vegetation, which isnormally shaded out, develops a sod that gradu-ally encroaches on the channel banks. Forbenthic macroinvertebrates, microbes, and al-gae, which live in and on the stream bed, theloss in stream width translates into a propor-tional loss of habitat. The effects of channelnarrowing on fish habitat are more complex andinvolve the influence of woody debris on thepool and riffle structure.

Links between large woody debris in streams,the abundance of fish habitat, and the popula-tions, growth, and diversity of fishes have beendocumented. Even when the selection methodof tree harvesting has been done along streams,the removal of old growth has caused a declinein aquatic habitat quality because of diminishedinputs of large woody debris. The surfaces ofsubmerged logs and roots provide habitat thatoften support macroinvertebrate densities farhigher than on the stream bottom itself.

Woody debris, like boulders and bedrock pro-trusions, tends to form pools in streams bydirectly damming flow, by the scouring effectsof plunge pools downstream of fallen logs, or byforming backwater eddies where logs divertflow laterally. In undisturbed forests, largewoody debris accounts for the majority of poolformation. As expected, removal of woody de-bris by deforestation typically results in loss ofpool habitat. Although pools are spatially con-tiguous with riffles, there is little or no overlapin the species composition of the dominantmacroinvertebrates occurring in the two habi-tats. The loss of pools, therefore, translatesdirectly into lower populations and diversity forthis group. For fish, pools improve habitat byproviding space, cover, and a diversity of micro-environments. Greater depth and slower veloc-ity in pools afford protection to fish duringstorms, droughts, and other stressful conditions.

Debris dams of large woody material block thetransport of both sediment and smaller littermaterials. The impoundment and delayed trans-port of organic material downstream enhancesits utilization by aquatic organisms. By slowingtransport rates, dams on small order streamsserve as buffers against the sudden deposition ofsediment downstream. The capacity of a streamto retain debris, therefore, is an important char-acteristic influencing the aquatic habitat.

Although it is often thought that large woodydebris is less important on large rivers and openwater habitats, it has been shown that woodydebris derived from riparian forests along tidalshorelines of the Bay provides an important ref-uge habitat for numerous species of fish andcrustaceans. Shallow water habitats, with plen-tiful large woody debris, support greaterabundance of many species of fish and crusta-ceans than do areas with no woody debrisbordered by narrow strips of marsh. Studieshypothesize that the importance of large woodydebris along Bay shorelines has been increasedbecause of loss of habitat in submerged aquaticvegetation and oysterbeds.

Section III

3-6

3. Food Webs and Species Diversity

The two primary sources of food energy input tostreams are litterfall (leaves, twigs, fruit seeds,and other organic debris) from streamsidevegetation and algal production within thestream. Total annual food energy inputs (litterplus algal production) are similar under shadedand open canopies, but the presence or absenceof a tree canopy has a major influence on thebalance between litter input and primary pro-duction of algae in the stream.

Studies noted that “streams flowing througholder, stratified forests receive the greatestvariation in quality of food for detritus-processing organisms.” In the Piedmont,streams flowing through forested landscapes donot contribute food energy to downstream chan-nels that have been deforested (even contiguousreaches) because the large pieces of litter do notmove very far. This means that a streamsideforest is needed along the entire length of astream in order to assure a proper balance offood inputs appropriate to the food chain of na-tive species. Macroinvertebrate populations areaffected by changes in litter inputs. The activityof benthic organisms may increase followingstreamside plant removal. Woody materialdecomposes more quickly following riparianforest removal, thereby further reducing thestream's nutrient retention.

The quantity and quality of algal production in astream are greatly affected by the quantity andquality of light striking its surface. For exam-ple, studies showed that the algal community ofa stream heavily shaded by an old growth forestwas dominated by diatoms all year, while anearby stream in a deforested area containedmainly filamentous green algae in the spring anddiatoms at other times. Other studies have alsoshown that deforested sites tend to be dominatedby filamentous algae while diatoms prevail un-der dense canopy cover. In the easternPiedmont, filamentous algae such as Clado-phora can be dominant in deforested streamsdue primarily to a combination of high nutrients,high light levels, and warm temperatures. Al-though some macroinvertebrates such as

crayfish and waterboatmen insects readily con-sume this type of algae, most herbivorousspecies of stream macroinvertebrates haveevolved mouth parts specialized for scrapingdiatoms from the surface of benthic substratesand cannot eat filamentous algae.

The influence of differences in the quality ofalgal production on the aquatic ecosystem iscomplex. Algal grazing species generally bene-fit from an increase in algal growth. Becausethe growth efficiency of insects is often higheron algae than on detritus, the opening of thecanopy may increase the production of macroin-vertebrates in these reaches. For example,studies found both higher biomass and densitiesfor most grazer species in deforested sites rela-tive to forested sites. The pattern is not clear,however, because other studies found higherbiomass but lower densities of grazers in defor-ested versus forested sites. Researchersobserved in California streams that the benthiccommunity in logged watersheds became domi-nated by a few algal feeding species. Thediversity of the macroinvertebrate communitywas significantly lower than in unlogged water-sheds, except where the stream was protected bya riparian buffer of 30 meters or more. Forbuffer strips less than 30 meters in width, theShannon diversity was significantly correlatedwith buffer width.

How Riparian Forest BuffersFacilitate Removal of NonpointSource PollutantsRiparian forests remove, sequester, or transformnutrients, sediments, and other pollutants. Thepollutant removal function of a Riparian ForestBuffer System depends on two key factors:

• The capability of a particular area to inter-cept surface and/or groundwater-bornepollutants, and

• The activity of specific pollutant removalprocesses.

Section III

3-7

Focusing on these two factors as regulators ofbuffer zone effectiveness is useful for evaluatingthe importance of a particular site as a buffer.

1. Nitrate Removal

Most studies with high levels of nitrate removalwere in areas with high water tables that causedshallow groundwater to flow through or near theroot zone. The mechanisms for removal ofnitrate in these study areas are thought to be acombination of denitrification and plant uptake.Denitrification is the biochemical reduction ofnitrate or nitrite to gaseous nitrogen, either asmolecular nitrogen or as an oxide of nitrogen.Linkages between plant uptake and denitrifica-tion in surface soils have been proposed as ameans for maintaining high denitrification ratesin riparian ecosystems. In contrast, ripariansystems without substantial contact between thebiologically active soil layers and groundwater,or with very rapid groundwater movement, ap-pear to allow passage of nitrate with only minorreductions in concentration and load. A studyreported both high nitrate concentrations andhigh nitrate removal rates beneath a riparianforest where very high nitrate flux and rapidgroundwater movement through sandy aquifermaterial limited nitrate removal efficiency. An-other study showed that groundwater flowbeneath the biologically active zone of a narrowriparian buffer along a tidal bay in Marylandresulted in little removal of nitrate. It is alsoknown that groundwater discharging throughsediments of tidal creeks may have up to 20times the nitrate concentrations found in themain stem of the creeks. A study indicated thatgroundwater nitrate might bypass narrow areasof riparian forest wetland and discharge intostream channels relatively unaltered when theforest is underlain by an oxygenated aquifer.This pattern of groundwater flow was supportedby modeling of a small Coastal Plain watershedin Maryland. Isotopic analysis of groundwaterand surface water in this watershed suggestedthat denitrification was not affecting the nitrateconcentrations of discharging groundwater. Inthese cases where nitrate enriched water sur-

faces in the stream channel, a wide RFBS wouldhave little effect on nitrate. Deeply rootedvegetation near the stream might have some ef-fect.

Studies in New Zealand have shown that themajority of nitrate removal in a pasture water-shed took place in organic riparian soils whichreceived large amounts of nitrate laden ground-water. The location of the high organic soils atthe base of hollows caused a high proportion ofgroundwater (37-81%) to flow through the or-ganic soils although they occupied only 12percent of the riparian area. A related study inNew Zealand found very high nitrate removal inthe organic riparian soils, but streamflow wasstill enriched with nitrate. The authors specu-lated that water movement through mineral soilswas responsible for most of the nitrate transportto streams. Riparian systems with interminglingorganic and mineral soils point out the need tounderstand where groundwater is moving andwhat types of soils it will contact, especially inseepage areas.

2. Plant Uptake of Nutrients

Maintenance of active nutrient uptake by vege-tation in Zone 2 should increase the potential forshort-term (non-woody biomass) or long-term(woody biomass) sequestering of nutrients. Al-though plant water uptake is chiefly a passivetranspiration process, plant nutrient uptake ismostly an active process, dependent upon plantmetabolic activity.

Nutrient uptake by flood-intolerant plants isstrongly influenced by the aeration status of thesoil. As low oxygen supply decreases rootmetabolism, the uptake of most nutrients de-creases. Flood-tolerant species, such as thosefound in many riparian forests, may toleratelow-oxygen conditions by means of adaptivemetabolic responses. They may also avoid rootanoxia by morphological adaptations that fa-cilitate the availability of oxygen. Underflooded conditions, roots may become thickerand increase in porosity, allowing an internaldownward diffusion of oxygen. The growth ofadventitious roots may also allow water and nu-

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trient uptake from near-surface areas that aremore aerated. Vegetation selection for restoredor managed RFBS must consider the ability ofdifferent species to take up and store nutrientsunder specific conditions of the site. A studypoints out that flooding can enhance the nutrientuptake and growth of some species. Bottomlandhardwood seedlings grow faster under saturatedconditions than under drained but well-wateredconditions. More rapid increases in total dryweight and nitrogen and phosphorus uptakewere found in water tupelo (Nyssa aquatica L.)as well as several other species under saturatedconditions. Shoot weights of a majority of wet-land and intermediate plant species were eitherunaffected or increased under flooded condi-tions.

Compared to the “natural” riparian forests stud-ied in most existing research, managed riparianforests have the potential for increased accu-mulation of nitrogen and phosphorus in biomassthrough both increased biomass production andincreased foliar nutrient contents. Trees canrespond to nitrogen subsidy by both increasedgrowth rates and luxury nitrogen uptake. Thegrowth rate of forests is commonly nitrogenlimited. A study suggested that high efficiencyof nitrogen use by forests is an adaptation to thenitrogen-deficient environments that they fre-quently inhabit. Often the potential nitrogenuptake rate is much higher than observed rates.

Conditions do exist where nitrogen is no longerthe limiting nutrient for forest growth. Long-term inputs of nitrogen, such as may occur fromatmospheric deposition in the northeasternUnited States, could result in nitrogen levelsexceeding the total combined plant and micro-bial nutritional demands. Under theseconditions, phosphorus might become the lim-iting factor for tree growth. Unlike uplandforests, phosphorus may often be the most lim-iting nutrient in wetland ecosystems. A studyfound the growth of baldcypress (Taxodium dis-tichum (L). Rich.) in a southern Illinois swampto correspond well with phosphorus inputs fromflooding. Foliar phosphorus content of loblollypine on wet Coastal Plain sites in South Caro-

lina has been observed to correlate well withgrowth. An analysis of nutrient ratios in de-caying litter from tupelo gum trees in a NorthCarolina swamp forest suggested that phospho-rus levels may limit decomposition rates. Ifphosphorus is the limiting nutrient for treegrowth, it should make vegetation an effectivephosphorus sink.

While several studies have found plant uptake tobe an important nutrient removal mechanism inriparian forest buffers, several factors may re-duce the importance of plants as nutrient sinks.Pollutants in groundwater flowing into the ri-parian buffer will only be accessible to plants ifthe water table is high in the soil profile or ifmass movement of water because of transpira-tion demands moves water and solutes into theroot zone. Coastal Plain riparian forests havebeen shown to control localized downslope wa-ter transport by creating moisture gradientswhich move water in unsaturated flow fromboth the adjacent stream and the upland field.Nutrients in surface runoff and in water perco-lating rapidly through soil macropores as“gravitational water” may not be available toplants. Large rainfall events that often transporta high percentage of pollutants in the Chesa-peake Bay Watershed (CBW) often produceconcentrated surface flow and macro-pore-dominated percolation.

Plant sequestering of nutrients is also limited byseasonal factors. In the temperate deciduousecosystems that dominate riparian forest buffersin the CBW, plant uptake will decline or stopduring the winter season. A high percentage ofsurface and groundwater flow occurs in theCBW during winter. There is also concern thatnutrients trapped in plant tissues can be releasedback into the soil solution following litterfalland decomposition. However, nutrients releasedfrom decomposing plant litter may be subject tomicrobial, physical or chemical attenuationmechanisms in the root zone of forest soils.Storage of nutrients in woody tissue is a rela-tively long-term attenuation, but still does notresult in removal of pollutants from the ecosys-tem unless biomass is removed. A final concernabout plant uptake as a nutrient removal mecha-

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nism arises from the possibility that the abilityof trees in a buffer zone to sequester nutrients inwoody biomass becomes less as trees mature.The average tree age in most riparian forestbuffers in the CBW is less than 100 years andshould thus be accumulating nutrients in woodybiomass. Although net vegetation accumulationof nutrients may reach zero, net ecosystem ac-cumulation may continue as nutrients are storedin soil organic matter.

3. Microbial Processes

In addition to plant uptake, there are microbialprocesses that attenuate pollutants in RFBS.These processes include immobilization of nu-trients, denitrification of nitrate and degradationof organic pollutants. Microbes take up or“immobilize” dissolved nutrients just as plantsdo. These immobilized nutrients can bere-released or “mineralized” following deathand decomposition of microbial cells, just asnutrients sequestered by plants can be releasedfollowing litterfall. In ecosystems that are ac-cumulating soil organic matter, there will be anet storage of immobilized nutrients. Riparianforest buffers, if managed to foster soil organicmatter accumulation, may thus support signifi-cant long-term rates of nutrient storage byimmobilization.

Denitrification refers to the anaerobic microbialconversion of nitrate to nitrogen gases. Denitri-fication is controlled by the availability ofoxygen (O2), nitrate, and carbon (C). Althoughessentially an anaerobic process, denitrificationcan occur in well-drained soils because of thepresence of anaerobic microsites, often associ-ated with decomposing organic matter fragmentswhich deplete available oxygen. It is likely thatsoil moisture gradients in riparian ecosystemscause a change in controlling factors withinmost three-zone RFBS. In parts of the RFBSwith better internal drainage and generally lowersoil moisture conditions, denitrification may begenerally limited by the interacting factors ofcarbon availability and aeration status. Al-though many wetlands are often assumed to

have high levels of denitrification because ofhigh carbon soils and anaerobic conditions, de-nitrification in many wetlands will be nitrogenlimited. In the more poorly drained or wetlandportions of an RFBS, denitrification is morelikely to be limited by nitrate availability.

Wetland soils develop high levels of organicmatter because of their slope position and hy-drologic condition. Frequently inundated soilswill have lower rates of litter decompositionbecause the flow of carbon from litter to micro-bial populations is reduced under anaerobicconditions. The interactive nature of oxygen,nitrate, and carbon control of denitrificationmeans that more denitrification generally occursin intermittently flooded sites than in perma-nently flooded conditions.

Denitrification has been identified as the keynitrate removal mechanism in several riparianforest buffer studies. Estimates in the range of30 to 40 kilograms of nitrogen per hectare peryear have been reported for natural riparian for-ests in the United States. In several studies ofdenitrification in riparian ecosystems, denitrifi-cation has been concentrated in surface soil andrates are generally much lower below the top 12to 15 centimeters of soil. A study reported veryhigh denitrification in the top 30 centimeters ofan organic riparian zone soil in New Zealand.Denitrification rates (measured on anaerobicsoil slurries) were over 11 kilograms of nitrogenper hectare per day at this site.

While the factors regulating denitrification insurface soils and aquifers are relatively well un-derstood, the amounts of direct denitrification ofgroundwater-borne nitrate are much less wellestablished. Subsurface microbial activity isusually limited by carbon availability. In set-tings where the total and dissolved carboncontents of aquifers are low, they are poor qual-ity substrates for microbial growth, andanaerobic conditions necessary for denitrifica-tion to proceed are not generated.

Microbial attenuation of organic compoundsarises from their ability to degrade these com-pounds as food sources or through non-energyyielding “cometabolism” reactions. There are

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many different microbial degradation mecha-nisms including aerobic, anaerobic,chemoautotrophic and heterotrophic pathways.The wide range of environments and high diver-sity of microbial metabolism in RFBS shouldsupport many of these mechanisms. Furtherresearch into specific management strategies tofoster a wide range of degradation strategies isneeded.

In many cases, riparian area retention ofgroundwater-borne pollutants may depend on acomplex interaction of hydrology, plant, soil,and microbial factors. The potential importanceof these interactions is hypothesized based onstudies where significant rates of nitrate removalfrom groundwater were measured, but the po-tential for denitrification in the subsurface waslow. Studies suggested that surface soil denitri-fication of groundwater derived nitrate is animportant route of nitrogen removal in riparianforests. This route depends on plant uptake ofnitrate from groundwater, decomposition andnitrogen release from plant litter, and nitrifica-tion and denitrification of this nitrogen insurface soil. In riparian forests where this routeof nitrogen removal is important, the nitrateremoval function may depend on complex inter-actions among hydrology, plant dynamics, andsoil microbial processes. These interactionsvary within and between riparian forests andshould be strongly influenced by soil drainageclass, vegetation and soil type, climate, andgroundwater quality. Although soil denitrifica-tion should be sustainable indefinitely underproper conditions with a supply of nitrate andavailable C, a study found that long-termgroundwater nitrate loading led to symptoms ofnitrogen saturation in the surface soils of a ri-parian forest buffer.

4. Removal of Surface-BornePollutants

Sediment trapping in riparian forest buffers isfacilitated by physical interception of surfacerunoff that causes flow to slow and sedimentparticles to be deposited. Effective sedimenttrapping requires that runoff be primarily sheet

flow. Channelized flow is not conducive tosediment deposition and can actually cause ero-sion of the RFBS. Two studies on long-termsediment deposition in riparian forests indicatedthat it is substantial. Results of both studies in-dicate that two main actions occur:

• The forest edge fosters large amounts ofcoarse sediment deposition within a fewmeters of the field/forest boundary, and

• Finer sediments are deposited further into theforest and near the stream.

Two other studies found much higher depths ofsediment deposition at the forest edge than nearthe stream. A second peak of sediment depthwas often found near the stream, possibly fromupstream sediment sources deposited in over-bank flows. The surface runoff which passesthrough the forest edge environment is muchreduced in sediment load because of coarsesediment deposition, but the fine sediment frac-tion is enriched relative to total sediment load.These fine sediments carry higher concentra-tions of labile nutrients and adsorbed pollutantswhich are carried further into the riparian forestand are deposited broadly across the RFBS.

Movement of nutrients through the RFBS insurface runoff will be controlled by a combina-tion of the following:

• sediment deposition and erosion processes,

• infiltration of runoff,

• dilution by incoming rainfall/throughfall, and

• adsorption/desorption reactions with forestfloor soil and litter.

Studies that separate the effects of these variousprocesses are not available. A study found largereductions in concentrations of sediment, am-monium-nitrogen, and ortho-phosphorus insurface runoff which passed through about 50meters of a mature riparian forest in the Mary-land Coastal Plain. Although the concentrationsof these pollutants were reduced by a factor ofthree or four in most cases, the flow-length wasabout twice that recommended in the RFBSspecification. Another study found that dis-

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solved ortho-phosphorus loads in surface runoffwere not reduced markedly in a Zone 2-like areaof the riparian forest. The studies of surfacerunoff through riparian forests agreed on theimportance of eliminating channelized flowthrough the riparian forest and recommendedspreading flow before it reached the forestbuffer. In-field practices are also critical in pre-venting channelized flow from reaching the fieldedge.

Integrated Water QualityFunctions of Riparian ForestBuffer Systems

The need to simultaneously control at least threemajor transport mechanisms of waterborne pol-lutants creates potential difficulties for RFBS.It is likely that control of pollutants transportedin the sediment-adsorbed phase of surface run-off, the dissolved phase of surface runoff, andgroundwater (dissolved phase only) may be op-timal on different sorts of RFBS with differingsoils, vegetation, and management.

For surface-borne pollutants, increasing infiltra-tion in the RFBS will be an effective measurefor both dissolved and adsorbed pollutant con-trol. Conversely, the sandy well-drained soilswhich have highest infiltration will likely havelowest denitrification rates and may have rapidgroundwater movement rates leading to highrates of nitrate transport through the riparianforest buffer.

For nitrate removal via denitrification, a riparianecosystem where high nitrate water moves intohigh organic matter soils or subsoils is the bestway to promote denitrification and the best wayto permanently remove nitrate from the soil-water-plant system. This is illustrated both bythe New Zealand riparian studies of organic ri-parian soils and by the findings thatdenitrification is highly stratified in mineralsoils with most denitrification occurring in thehigh organic carbon surface soils. Organic-richwetland soils can often respond to increasednitrate loads with increased denitrification. Thesame conditions which are likely to promote

denitrification are also likely to decrease theamount of retention of surface-borne pollutants.Wetland soils which are frequently inundatedwill have little or no infiltration capacity oravailable water storage capacity.

Loading Rates and NonpointSource Pollution ControlAs a nonpoint pollution control practice, Ripar-ian Forest Buffer Systems represent a long-terminvestment which can change landscape struc-ture. As a long-term management option, it isquite likely that RFBS will be exposed to a widerange of pollutant loadings because of both in-terannual variation and changes in managementpractices in source areas. Information on howmature RFBS respond to changing pollutantloads is essential to understanding long-termsustainability of RFBS. Some research onCoastal Plain RFBS indicates that higher ratesof nitrate removal would be possible underhigher loadings of nitrate. Published studiesindicate that this is most likely to be true in ar-eas where denitrification is the primary meansof nitrate removal. Given the range in nutrientuptake observed both among different plant spe-cies and within the same plant species, it islikely that vegetation uptake will increase withincreasing loads, if there is significant hydro-logic interaction with vegetation.

Increasing loads of phosphorus are likely to beless effectively controlled than increasing loadsof nitrogen, because of the lack of biologicalprocesses to remove or sequester phosphorus inthe RFBS. If increasing phosphorus loads are tobe controlled, it will require effective manage-ment of Zone 2 for infiltration and both Zones 2and 3 for sediment removal. If dissolved orparticulated phosphorus can be retained in theroot zone, it will be available for both biologicaland chemical removal processes. If RFBS havesome absolute removal potential for phosphorus,reducing input loads should increase the effi-ciency of removal.

Management to control increasing loads ofsediment and sediment-borne chemicals willrequire specific management for sediment re-

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tention. Most of the mass of sediment will bedeposited in Zone 3 or in the upper portions ofZone 2 and most of the sediment-borne nutrientswill be deposited downslope in Zone 2. In-creased sediment loadings will require increasedmanagement to eliminate concentrated flows,remove accumulated sediment, especially inberms, and restore the herbaceous vegetation.Increased sediment and sediment-borne chemi-cal loads should lead to higher amounts ofchemical deposition in surface litter. The abilityof RFBS to retain dissolved phosphorus, espe-cially under high loadings, may be limited.

Loading rate/buffer width relationships are onlypoorly defined, especially for dissolved pollut-ants. In published studies with water clearly incontact with surface litter or the biologicallyactive root zone, buffers of about 100 feet havebeen effective for at least sediment and nitrateremoval. One of the difficulties in describingthese relationships is that increasing pollutantloads may also be accompanied by increasingwater volumes in either surface runoff, ground-water, or both. In the presence of increasedwater movement, denitrification for nitrate re-moval should be enhanced and sedimentationand infiltration may be decreased. Increasedsurface runoff and loading of sediment andsediment-borne chemicals can be accommo-dated by management to increase roughness andcontrol channelized flow.

Stream Order and Size Effects

Regardless of the size of stream or the hydro-logic setting, water moving across the surface orthrough the root zone of a RFBS should showreduction in either nitrate (groundwater) orsediment and sediment-borne chemical loadsreaching the stream. As streams increase insize, the integrated effects of adjacent riparianecosystems should decrease relative to the over-all water quality of the stream. On lower orderstreams there is greatest potential for interac-tions between water and riparian areas. ForNPS pollution control, the change in impact ofRFBS as stream order increases can be esti-

mated based on hydrologic contributions fromupstream and from the riparian ecosystem.

For first-order streams, the potential impact ofthe RFBS on chemical load or flow-weightedconcentration is directly proportional to the pro-portion of the excess precipitation from thecontributing area which moves through or nearthe root zone or surface of the RFBS. For allstreams above first order, the contributing areais only one source of pollutants, with upstreamreaches providing the other source.

For second-order and above, the NPS pollutioncontrol function of a given RFBS is based onboth the proportion of water from the contrib-uting area which moves through the ripariansystem and the relative sizes of the two potentialpollutant loads - upstream sources or adjacentland uses. Clearly, the larger the stream, theless impact a RFBS along a particular streamreach can have on reduction in overall loadwithin that reach. If there are no RFBS up-stream from a particular stream reach, the waterentering the stream reach is likely to be alreadycontaminated.

On a watershed basis, the higher the proportionof total streamflow originating from relativelyshort flow-paths to small streams, the larger thepotential impact of RFBS. In comparing thepotential effectiveness of RFBS among water-sheds, drainage density (length of channel perunit area of watershed) should provide a usefulstarting point. Higher drainage density impliesgreater potential importance for RFBS in NPSpollution control.

Control of the stream environment is most ef-fective when native vegetation forms a completecanopy over the stream. This is obviously onlypossible on relatively small streams. The effectof the RFBS on the stream environment is notsimply proportional to the amount of the chan-nel that is shaded. As previously noted, besidesdirect shading of the stream channel, cooling ofgroundwater, recharging streams, and provisionof bank habitat will occur even on largerstreams. Providing for bank habitat, largewoody debris and leaf detritus remain importantfunctions, regardless of stream size.

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Stormwater Management

Retaining forests as open space and using ri-parian forest buffer corridors can be effectivepractices to integrate with stormwater planningin urbanizing areas. Forests can capture, absorb,and store amounts of rainfall 40 times greaterthan disturbed soils, like agricultural fields orconstruction sites, and 15 times more than grassturf or pasture. Capitalizing on this ability toreduce the amount of water available for storm-water runoff is a function that makes forestsvaluable as an “open space tool” for stormwaterreduction. Fairfax County, VA, recently esti-mated that forests were providing almost $57million in stormwater reduction benefits annu-ally to local taxpayers.

A buffer network acts as the right-of-way for astream and functions as an integral part of thestream ecosystem. Buffers can be an importantcomponent of the stormwater treatment systemof a development site. They cannot, however,treat all the stormwater runoff generated withina watershed. In heavily urbanized watersheds,only 10 percent or so of water contributing tostormflow may end up passing through a bufferarea. When buffers can be designed to acceptflow directly from impervious areas – such ascuts in roadside curbs – a narrow stone layer, agrass filter strip, or some other method, can beused to spread water. The buffer can betterfunction as a direct filtering system. Roadsideswales or small collection areas just outside theforest buffer may also provide a means to slowlyrelease and spread stormflow for treatment bythe buffer. Locating larger ponds and wetlanddetention areas in or adjacent to buffers willalways be a balancing act. However, thesepractices can be designed to work well in tan-dem.

Flood Reduction and ControlStreams and their valleys in the Chesapeake BayWatershed were formed in a hydrologic balancewith their forested watersheds. The capacity ofdownstream channels was also influenced byforested flood plains. Forested flood plainstemporarily store flood waters, and woody

vegetation helps reduce and capture sedimentloads.

Human activities have changed the hydrologicbalance between channels and their watersheds.Some examples of changes are:

• Forested lands have been cleared, resultingin increased storm runoff.

• Drainage efficiency has been increasedthrough channelization, gully formation, orthe removal of large woody debris, resultingin rapid surface runoff.

• The construction of dikes and levees has in-creased downstream peaks.

• Flooding is increased by deposition andstream aggradation.

• Channels are cleaned and cleared of snags,resulting in increased flood velocities.

• Eventually channels are downcut, and theforce of bankfull flows is increased.

The influence of past human use will still affectthe hydrology of watersheds that have becomereforested, and the function of reestablishedriparian forests will sometimes be limited byexisting watershed and channel conditions.

Flood Plain Function

The Federal Flood Plain Assessment Reportcalls for restoring the natural function of floodplains. The natural flood control functions offlood plain forests include the following:

• Retarding flood flow velocities is the pri-mary beneficial function of flood plainforests. The U.S. Geological Survey devel-oped a procedure for determining the rate atwhich increasing the number of woody stemsincreases flood plain roughness, thereby re-ducing flood velocity. The role of woodystems in reducing velocity and increasingsediment deposition during floods has beenwell documented. By comparison, grasscovered flood plains, when submerged, donot retard flow.

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• Maintaining downstream flood control ca-pacities. Colonization of riparian areas withwoody vegetation can dramatically decreasethe rate of sedimentation in a downstreamreservoir. This can help maintain the floodstorage capacity of small reservoirs.

• Streamside forests contribute to channel sta-bility and roughness. They contribute largewoody debris that prevents downcutting,traps bedload sediments, and dissipatesstream energy in plunge pools.

The natural resources manager should assess thesite-specific opportunities to restore flood plainfunctions with riparian forest buffers. The fol-lowing are areas that should receive specialattention and consideration:

• In headwaters - By restoring forests alongsmaller streams, more storm flow can be dis-persed and retained higher in the watershed,thus reducing flood heights and damagealong downstream rivers

• Along downcut channels - Where channelsare contained within steep banks, and thestream reaches the former flood plain lessfrequently, the opportunity to restore floodplain function will be reduced.

• Channels with levees - Where stream accessto the flood plain is blocked by levees, theflood plain function is lost. However, estab-lishing trees on the levee will help protectthe levee and provide other benefits. Studiesby the Agricultural Research Service indicatethat rock-faced revetments with woodyvegetation suffered less damage duringfloods. Similar results were observed fol-lowing the 1993 Mississippi River floodswhere tree-covered levees withstood over-topping better than grass-covered levees.

• Watershed – Consideration must be givento the following upstream conditions thatincrease the frequency of flooding:

1) Land development2) Addition of levees3) Clearing and snagging operations4) Clearing streamside trees

Downstream considerations that reduce thestream’s access to the flood plain include:

1) Potential for dredging and channelclearing

2) Presence of active headcuts

• Channel type - Many types of stream chan-nels do not have active flood plains.Channels with the National Wetland Classi-fication of “lower perennial” are more likelyto have flood plains.

• Period of inundation - Areas that are inun-dated for extended periods will limit theselection of suitable woody vegetation.

Opportunities for ManagementRestoring a streamside forest with the attendantunderstory and ground cover will make a sig-nificant difference in flood plain function.Periodic harvesting will keep those functions atan optimum by:

1) Opening the canopy to increase the num-ber of woody stems that retard velocity.

2) Harvesting to control tree size which isimportant where there are levees.

Wildlife and Fish HabitatFunctions/Values of Riparian

Forest Buffer Systems

Riparian areas are used by wildlife more thatany other type of habitat. Many resource man-agers are aware of the water quality values ofriparian areas, but many are not aware of thedirect effects these areas have on wildlife, bothaquatic and terrestrial.

Riparian areas provide valuable habitat in manyforms for different types of wildlife. Establish-ing, managing, and protecting these areas can

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increase biodiversity. Aquatic biodiversity, inmany cases, is dependent on the quality of theriparian areas. Equally important is the value ofthese areas for terrestrial wildlife. They providevaluable wildlife corridors, many of which havebeen lost over the years, for agriculture expan-sion and housing development.

The primary determinants of stream flora andfauna are water abundance and quality and theecological character of the riparian area, as wellas the watershed as a whole. The ripariansystem provides a reflection of the surroundingterrestrial ecosystems. Removal or degradationof riparian areas can have a domino effect with

negative results in both aquatic and terrestrialecosystems that are linked to it.

Riparian Area Importance toWildlifeThe major reasons why riparian areas are soimportant to wildlife are:

• Wildlife habitat is composed of cover, food,and “water.”

• The greater availability of water to plants,frequently in combination with deeper soils,increases plant production and provides a

Figure 3 - 2. Benefits of Riparian Forest Buffers. (Source: Alliance for the Chesapeake Bay, January 1996)

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suitable site for plants that could not occur inareas with inadequate water. This increasesplant diversity.

• The shape of many riparian areas, particu-larly their linear meandering nature alongstreams, provides a great deal of productiveedge.Riparian areas frequently produce moreedge within a small area.

• Along streams, there are many layers ofvegetation exposed in stair step structure.The stair step of vegetation of contrastingform (deciduous vs. coniferous, shrubs vs.trees) provides diverse nesting and feedingopportunities for wildlife.

• Riparian areas along intermittent and perma-nent streams and rivers provide travel routesfor wildlife. These may serve as forestedconnectors between wooded habitats. Wild-life may use such habitat for cover to travelthrough otherwise unforested agricultural orurban areas.

Principles of the RiparianEcosystem

Definition of Terms

To better understand the important wildlife val-ues that riparian areas provide, concepts of theecosystem and the food web are addressed first.An ecosystem is the area in which one lives.Derived from “Eco,” which is the Greek wordmeaning “Home,” ecology is the study of the“Home.” So, an ecosystem is the “system” or“make up” of one’s “home.” This home couldbe as small as under a rock in a stream or aslarge as the entire Chesapeake Bay Watershed.When thinking about the importance of riparianareas to wildlife, the type and species of wildlifebeing managed must be considered along withrelative ecosystem size. Smaller systems areconnected to a larger ecosystem, providing thebase support for the larger system.

An ecosystem includes populations, communi-ties, habitats, and environments, and itspecifically refers to the dynamic interaction ofall parts of the environment, focusing particu-

larly on the exchange of materials between theliving and nonliving parts.

A population is a group of interacting individu-als, usually of the same species, in a definablespace. A community, in the biologic sense,consists of the population of plants, animals,and microorganisms living together in a givenplace.

The terms environment and habitat refer to adefinable place where an organism lives, in-cluding both the physical and biologic featuresof the place. The word environment comesfrom the French verb “environner,” to surround,and means surrounding or something that sur-rounds. It includes all the conditions,circumstances, and influences surrounding andaffecting an organism or group of organisms.

A habitat is the natural abode or locality of ananimal, plant, or person. It is derived from theLatin, “habitare” - to “dwell.” It also includesall features of the environment in a given local-ity.

The term abiotic means “without life ornonliving.” Many substances such as water,oxygen, sodium chloride, nitrogen, and carbondioxide are abiotic when they are physicallyoutside living organisms. However, once theyare within living organisms they become part ofthe biotic world. An important property of anecosystem that determines its productivity is theform and composition in which bioactive ele-ments and compounds occur. For example, anecosystem may have an abundance of vital nu-trients, such as nitrates and phosphates. If theyare present in relatively insoluble particulateform, as when they are linked to ferric ions, theyare not readily available to plants. When theyare in the soluble form of potassium or calciumnitrate and phosphate, they are more readilyavailable. One of the most important qualitiesof an ecosystem is the rate of release of nutri-ents from solids; this regulates the rate offunction of the entire system.

Photosynthesis is the basic production force inthe ecosystem, and it is dependent upon green

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plants, sunlight, water, carbon dioxide, and cer-tain inorganic ions.

The transfer of energy from plants through aseries of other organisms constitutes a foodchain. The term trophic (feeding) level refersto the parts of a food chain or nutritive series inwhich a group of organisms secures food in thesame general way. Thus, all animals that obtaintheir energy directly from eating grass such asgrasshoppers, meadow mice, and deer are partof the same trophic level.

The particular assemblage of trophic levelswithin an ecosystem is known as the trophicstructure. Typically, ecosystems have three tosix trophic levels through which energy and or-ganic materials pass. In more vernacular terms,food chains usually have three to six links, orgroups of organisms, which derive their nutri-tion similarly.

It may even be more appropriate to call suchtrophic structures food webs rather than foodchains. The interlocking nature of these rela-tionships is typical of other ecosystems. Thisinterlocking or interaction is extremely impor-

tant to the overall function and value of riparianbuffers.

StructureIt is very important for riparian areas to havestructure. Depending on the diversity of thearea, the structure can be very simple and notsupport a wide range of values for wildlife, or itcan be complex and supply a wide range of val-ues for many different species of wildlife.

Horizontal and vertical diversity are two com-ponents of habitat structure. Horizontaldiversity or “patchiness” refers to the complex-ity of the arrangement of plant communities andother habitats (see Figure 3-3). Different foresttypes have different wildlife communities. Ver-tical diversity refers to the extent to whichplants are layered in a stand (see Figure 3-4 onthe next page). The degree of layering is deter-mined by the arrangement of plant growthforms, by distribution of trees of varying heightsand crown characteristics, and by trees of thesame species but different ages.

It is important to think of structure and dynam-ics when managing a riparian area. Structurerefers to the spatial organization of communitiesand what part of the area populations utilize.Dynamics refers to the interactional processes,energetic relationships, and patterns of change

Figure 3 - 3. Horizontal diversity depends on the type of area and size-class management used on a property.(Source: DeGraaf, 1992)

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within communities. The riparian forest buffermay be thought of as a layered system, witheach layer possessing characteristic populationsand a typical organization.

One can obtain a partial glimpse of the dynamiccomplexity of the forest floor by carefully ex-amining the leaf litter of this biotic communityand by turning over a rotten log, or parting thegrass and herbaceous cover of the edges. Thesoil-air interface is a particularly rich and activearea for living organisms. There is a variety ofinsects, isopods, spiders, and myriapods (milli-pedes and centipedes), but those that are easilyseen represent only a small portion of the totalcommunity.

They are interacting with a great number ofsmaller forms—springtails, mites, and nema-todes. They are also part of the food chain ofvertebrates, such as salamanders, reptiles,shrews, mice, and ground dwelling birds, thatpatrol the area..

Reptiles and Amphibians that use ri-parian forested areas as their preferredhabitat:

• eastern ribbon snake

• eastern worm snake

• green frog

• Jefferson salamander

• mountain dusky salamander

• northern two-lined salamander

In moving upward from the floor of the riparianforest, the biotic community thins out to a cer-tain extent. Animals become more widelyspaced in three dimensions, and they becomemore mobile. The plant community is domi-nated by herbs and shrubs and the animalcommunity by insects, birds, and mammals.

Figure 3 - 4. Vertical diversity depends on the number of vegetative layers present in a stand.(Source: DeGraaf, 1992)

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Mammals that use riparian forested ar-eas as their preferred habitat:

• beaver

• big brown bat

• black bear

• eastern Pipistrelle

• Keen’s Myotis

• little brown Myotis

• long-tailed weasel

• mink

• northern short-tailed shrew

• raccoon

• river otter

• silver-haired bat

• Virginia opossum

Mammals, including deer, rabbits, mice, shrews,raccoons, and opossum, actively forage throughthe lower layer of the community. Many animalspecies, including annelids, some molluscs, my-riapods, and soil dwelling arthropods, do notenter this realm and are seldom if ever foundabove the surface of the ground. There are ex-ceptions, of course, such as certain snails(molluscs) which climb trees.

The intermediate, codominant, and dominantcanopy layers of the riparian forest, dominatedby the foliage of trees and vines, also have theircharacteristic animal communities. This is therealm of insects and birds. Relatively fewmammals penetrate these upper levels. Squir-rels, bats, and occasionally opossums andraccoons may be seen in this level, however.

Birds that use riparian forested areas as theirpreferred habitat:

• alder flycatcher

• American goldfinch

• bald eagle

• barred owl

• red-bellied woodpecker

• belted kingfisher

• cerulean warbler

• common yellowthroat

• eastern screech-owl

• eastern wood-peewee

• gray catbird

• Louisiana waterthrush

• northern rough-winged swallow

• northern waterthrush

• prothonotary warbler

• red herons

• red-shouldered hawk

• song sparrow

• tufted titmouse

• veery

• wood duck

• yellow-breasted chat

• yellow warbler

Stratification is evident in bird populations thatare obviously capable of ranging throughout theriparian forest from the floor to the canopy.Birds have definite preferences and tendenciesto frequent certain layers. Morley showed adefinite stratification of bird life: in the upper

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3-20

canopy, tree creepers (Certhia sp.); and robinsand wrens on the ground and the herbaceouszone. These patterns of vertical distributionreflect the feeding habitats of the birds and arean indication of the distribution of seeds andinsects.

Table 3-1 describes some plants used by com-mon songbirds for food, cover, and nesting.Morse has shown that the stratum distribution ofmany birds within the forest is further limited tospecific sites. He found, for example, that thebrown creeper (Certhia familiaris) and whitebreasted nuthatch (Sitta carolinensis) foragemainly on the lower part of tree trunks, whereasthe downy woodpecker (Dryobates pubescens)

and the Carolina chickadee (Parus carolinensis)forage on twig tips high in the canopy.

As described, these riparian forests provide ahome, or habitat, for many kinds of wildlife-game animals, songbirds, and many forms oftiny insects and animal life. Hundreds of kindsof plants make their home under this forest can-opy and could not exist without it. Theimportant elements of a wildlife habitat arefood, cover, and water. The combination andbalance of these factors determines the kinds ofwildlife to be found in any riparian forest area.Table 3-2 lists some wildlife food plants forspecific wildlife species and seasons available.

Section IIITable 3 - 1.

Native Plants Used by Common Songbirds for Food, Cover, and Nesting

PLANT BIRD

Bluebird

Thrush

Bunting Cardinal

Grosbeak

Catbird

Thrasher

Finch

Siskin

Jay Mockingbird Oriole

Tanager

Robin Sparrow

Junco

Titmouse

Nuthatch

Towhee Waxwing

Ash é é é é é

Bayberry é é é é é é

Bittersweet é é é é é é é

Blackberry é é é é é é é é é é é é

Blueberry é é é é é é é é é é é é

Cedar é é é é é é é é

Cherry é é é é é é é é é é é

Crabapple é é é é é é é é é é é

Dogwood é é é é é é é é é é

Elderberry é é é é é é é é é é é é é

Grape é é é é é é é é é é é é

Hawthorn é é é é é é é é é é é

Hickory é é

Holly é é é é é é é é é é é é

Honeysuckle é é é é é é é é é

Maple é é é é

Millet é é é é é é é

Mulberry é é é é é é é é é é é

Oak é é é é é é é é é é

Pine é é é é é é é é é é

3-2

1

Plum é é é é é é é

Section IIIPLANT BIRD

Bluebird

Thrush

Bunting Cardinal

Grosbeak

Catbird

Thrasher

Finch

Siskin

Jay Mockingbird Oriole

Tanager

Robin Sparrow

Junco

Titmouse

Nuthatch

Towhee Waxwing

Pokeberry é é é é é é é é

Pyracanthia é é é é é é é é é é

Rose é é é é é é é é

Sassafras é é é é é

Serviceberry é é é é é é é é é é é é é

Spicebush é é é é é

Spruce é é é é é é é é

Sumac é é é é é é é é é é é

Sunflower é é é é é é é

Viburnum é é é é é é é é é é

3-2

2

VirginiaCreeper

é é é é é é é é é

Section III

3-23

Table 3 - 2Wildlife Food Plants

No. of Species SeasonsPlant Species Wildlife Species Using Plants for Food Using Plants Availablea

Ash cardinal, purple finch, evening grosbeak, pine grosbeak, 20 Wcedar waxwing, yellow-bellied sapsucker, wood duck, bobwhite quail, black bear, beaver, porcupine, white-tailed deer

Blackberry brown thrasher, chipmunk, gray catbird, rabbit, 56 S, Fring-necked pheasant, robin, white-tailed deer

Cherry black bear, cedar waxwing, raccoon, red squirrel, rose- 56 S, Fbreasted grosbeak, ruffed grouse, white-footed mouse

Grape black bear, cardinal, fox sparrow, gray fox, 53 S, F, Wmockingbird, ruffed grouse, wild turkey

Ragweed dark-eyed junco, goldfinch, horned lark, mourningdove, red-winged blackbird, sparrows 49 F, W

Dogwood bluebird, cardinal, cedar waxwing, rabbit, ruffed 47 S, F, Wgrouse, wild turkey, wood duck

Oak black bear, blue jay, raccoon, ruffed grouse, 43 Sp, F,white-tailed deer, wild turkey, wood duck W

Sedge horned lark, ruffed grouse, sparrows, wild turkey 43 Sp, S

Serviceberry beaver, bluebird, cardinal, cedar waxwing, gray catbird, 39 Sp, Sred squirrel, scarlet tanager, white-tailed deer

Blueberry black bear, gray catbird, rabbit, rufous-sided towhee, 37 S, Fskunk, white-footed mouse, white-tailed deer

Elderberry bluebird, brown thrasher, cardinal, indigo bunting, 36 Srabbit, rose-breasted grosbeak

Pine beaver, black-capped chickadee, brown creeper 33 W

Panic grass dark-eyed junco, sparrows, red-winged blackbird, 32 Fwild turkey

Beech black bear, blue jay, chipmunk, porcupine, ruffed grouse, 31 Sp, Wsquirrels, tufted titmouse, white-tailed deer, wild turkey

Poison Ivy black-capped chickadee, gray catbird, downy woodpecker, 28 F, Wflicker, hairy woodpecker, hermit thrush, wild turkey

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Table 3 - 2 (cont.)Wildlife Food Plants

No. of Species SeasonsPlant Species Wildlife Species Using Plants for Food Using Plants Availablea

Sumac bluebird, cardinal, black-capped chickadee, hermit 28 F, Wthrush, rabbit, robin

Maple beaver, chipmunk, porcupine, rose-breasted grosbeak, 27 S, Fsquirrels, white-tailed deer

Pokeweed bluebird, cedar waxwing, gray catbird, gray fox, 25 Fmourning dove, raccoon, red fox

Greenbriar gray catbird, hermit thrush, mockingbird, raccoon, 23 F, Wruffed grouse

Birch black-capped chickadee, beaver, porcupine, rabbit, 22 Sp, Sruffed grouse

Virginia creeper bluebird, great-crested flycatcher, pileated 22 F, Wwoodpecker, red-eyed vireo

Hickory chipmunk, red-bellied woodpecker, rose-breasted 19 Sp, S,grosbeak, squirrels, wood duck F, W

Aspen beaver, porcupine, ruffed grouse, white-tailed deer 17 Sp, S,F, W

Hawthorn fox sparrow, gray fox, raccoon, ruffed grouse 15 S, F

Hemlock black-capped chickadee, porcupine, red squirrel, 13 F, Wruffed grouse, white-footed mouse

Walnut red-bellied woodpecker, beaver, fox squirrel, gray squirrel, 7 F, Wred squirrel

Yellow-poplar redwing blackbird, cardinal, chickadee, purple 14 Sp, Sfinch, goldfinch, hummingbird, yellow-bellied F, Wsapsucker, beaver, red squirrel, fox squirrel, graysquirrel, white-tailed deer

Alder beaver, goldfinch, ruffed grouse 11 Sp, S,F, W

___________________________________________________________________________________________Source: Adapted from Martin, A. C. et al. 1951.a Sp = spring, S = summer, F = fall, W = winter.

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Although the species that live in stream corri-dors differ from one part of the region toanother, all wildlife has similar basic needs:food, water, and shelter – collectively calledhabitat. In Maryland, different wildlife livesnear a fast-flowing, cool stream in the westernpart of the state than a slow-flowing, warmstream on the Eastern Shore, or near an urbanstream in central Maryland.

Travel CorridorsRiparian forests are transition zones betweenwet lowlands and drier upland habitats. Theyoften include a greater variety of plant types andhabitats than neighboring uplands areas. Theytend to be linear, creating a series of travel cor-ridors and natural edges from the water to theuplands. In areas of intensive farming, whereagricultural operations remove most crop resi-dues, riparian vegetation provides cover forreproduction, escape, nesting, and protectionfrom the weather. Where farmlands are bare formost of the year, riparian areas provide abun-dant food and water year-round.

Riparian forests also provide corridors for wild-life to move from one area to another. This isespecially important in winter, where cover isnearby and travel is easier because of reducedsnow depth. Young birds and mammals use ri-parian areas during dispersal from their birthplace. Migrating birds often use these areas andwetlands for resting. The wildlife trees (snagsand den trees) found in these areas are used ex-tensively for nest sites and perches. Riparianareas also serve as links between different typesof habitat, providing dispersal and travel routesfor species that would not otherwise cross largeopenings or cuts. It is extremely important thatthese riparian buffer corridors are linked toother areas of cover.

There were two studies conducted in the Chesa-peake Bay Watershed that examined the use offorest corridors by songbirds. One study exam-ined use of riparian buffers of different widthsby breeding birds. Those authors recommendeda minimum buffer width of 100 meters to attractbreeding neotropical migratory birds, becausemany of those species were not present in nar-

rower buffers. Yet, past research has indicatedthat, even if a species of songbird is present,reproduction success of that species may belower in narrow strips compared to larger habi-tat patches. Thus, only wide riparian buffersmay provide high-quality breeding habitat formany songbird species.

Another study conducted by the SmithsonianInstitution indicated that forest corridors, in-cluding riparian buffers, may be very importantfor songbirds during migration. In that study,more species of migratory songbirds were foundin large (greater than 500 hectares) rather thanin small (less than 100 hectares) forest tracts.This was the case whether or not the tracts wereconnected to other forests by corridors. How-ever, small tracts that were connected to otherforests by an intervening corridor supported sig-nificantly more species than did isolated smalltracts. Here, the presence of a corridor appar-ently increased the use of small forest tracts bymigrating birds, possibly by serving as a con-nection to other habitat patches.

The few studies conducted on wildlife use ofcorridors have suggested that corridors may bebeneficial for movement of individuals duringsome periods, but may not provide high-qualitybreeding habitats.

For example, riparian buffers that join withlarge forest tracts may not be needed to providehigh-quality breeding habitat for songbirds.These areas still may provide breeding habitatfor some reptiles, amphibians, or invertebratesand be useful connecting habitat for migratingsongbirds. In most cases, vegetation within ri-parian buffers should be planted or managed tomaintain both a high structural diversity and ahigh plant species diversity using native plantspecies.

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Fish Habitat

The Riparian Forest as a FoodSourceMacroinvertebrates, including aquatic insects,are important sources of food for fish. Thepresence or absence of riparian trees may be thesingle most important factor altered by humansthat affects the structure and functions of streammacoinvertebrates. Several changes occur in awatershed as a result of removing the riparianforest buffers. Watercourses become much nar-rower, resulting in less benthic area. Once treesare removed, grasses take over, sod forms, andthe stream narrows rapidly. Tree removal re-sults in loss of tree root systems, an importantcomponent of fish habitat.

Aquatic macroinvertebrates can be herbivores,detrivores (scavengers), carnivores (predators),or parasites. Aquatic insects can be classifiedby the specialized way in which they obtainfood as follows:

1. shredders – chew, mince, or gouge coarseparticulate detritus or live macrophytes (ex-ample - some caddisflies)

2. scrapers – scrape diatoms and other foodfrom rocks (example - mayflies, stoneflies)

3. collectors – gather fine particulate detritusloosely associated with the sediment or fromthe surface film (example - some caddis-flies)

4. piercers – pierce and suck the contents ofgreen plants or of animals (example - truebugs, waterstriders)

5. predators – attack live prey and ingest wholeor parts of animals (example - dragonfly,damselfly, hellgrammite)

6. parasites – live in or on aquatic animals, notnecessarily killing them

7. filter feeders – filter particles suspended inthe water column (example - blackflies,caddisflies that spin silk nets)

8. grazers – remove attached periphyton andmaterial closely associated with mineral ororganic substrates (example - mayflies,stoneflies)

As aquatic insects go through different stages intheir life cycles, they become different types offeeders.

Quality and quantity of food deteriorates whenriparian trees are removed. Loss of the forestcanopy allows high light levels to reach the wa-tercourses. This promotes the growth offilamentous green algae, which few, if any,aquatic species eat. Shade promotes diatoms, agood food source for all macroinvertebrates,especially caddisflies and mayflies. Seeds,twigs, and leaves are also a good source of dis-solved organic chemicals. The chemicalssupport beneficial bacteria, which in turn sup-port protozoans and higher forms of animal life.Some macroinvertebrates eat leaves directly. Itis not uncommon for small Pennsylvaniastreams flowing through forested land to containmore than 1,000 grams of leaf material persquare meter in November. In a healthy stream,most of the food is consumed by the followingApril. Leaves generally travel less than 220 feetfrom where they enter small streams and areeaten by mayflies and caddisflies.

Most species of insects seem to prefer andflourish best on a particular tree species. If pre-ferred trees are removed and replaced with lessdesirable species, some species of insects willvanish from a watershed. Sycamore is a goodspecies for most insects, as are sweet birch, riverbirch, and red maple. For example, certainstonefly species grow best by eating chestnutoak leaves. Some stoneflies need to eat theflowers of riparian trees in order to survive.Removal of the riparian forest eliminates treeflowers (food) that stoneflies must have to com-plete their life cycle. Some species ofcaddisflies need hollowed out twigs with whichto build a home, while others actually eat thewood for food (like termites do).

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How Sediments Adversely Affect FishHabitatSediment by weight is the largest single pollut-ant of water resources in the United States.Sediment entering watercourses is caused byrainsplash erosion and sheetwash erosion.Sediment reduces the productivity of aquaticplant, invertebrate, and vertebrate communities.It can threaten the survival of fish by coveringessential spawning grounds, covering eggs, andpreventing emergence of recently hatched fry.Sedimentation is one of the major causes of de-cline in the quality of fisheries throughout theUnited States. Turbidity in excess of 100 ppmcan inhibit fish growth and reproduction. Stud-ies have shown that 2mm of silt depositioncaused 100 percent mortality in white percheggs, and 0.5 to 1 mm of sediment caused 50percent mortality in adults.

The Use of Riparian Forest Buffersto Moderate Stream WaterTemperaturesWater temperature is very important in assess-ing water quality. As water temperatureincreases, the capacity of water to hold oxygendecreases. At elevated water temperatures,there is a risk of oxygen depletion as a result ofthe decomposition of organic matter.

Temperature also affects the release of nutrientsattached to sediment particles. As water tem-perature increases, the solubility of the nutrientsincreases. Slight increases in water temperaturecan produce substantial increases in the amountof phosphorus released into the water.

The removal of trees and other streamsidevegetation will cause detrimental effects. Dur-ing hot summer months, a stream that is notshaded will not be able to hold oxygen requiredfor aquatic life. Lack of oxygen, coupled withthe release of more nutrients into the water isdisastrous. An increase in sunlight and nutrientswill cause large algal blooms, further decreasingwater quality and aquatic habitat.

Temperature increases can cause a shift in theaquatic community from more desirable speciesto less desirable species that are more tolerant toelevated water temperatures. This is an impor-tant concern in the coldwater fish habitat of theChesapeake Bay Watershed. Water temperaturemust be controlled if the region is to promoteoutdoor recreation that includes an emphasis onfishing. In addition, if streamside vegetation isremoved from headwater areas, optimumbreeding areas for important game fish may bedestroyed. An increase in temperature in theseareas will cause fish to stop reproduction activi-ties.

Studies show that maintenance of forest buffersalong streams is an excellent way to moderatestream temperatures. One study comparedstream temperatures of two streams; one flowingthrough cropland and the other flowing througha forest (see Figure 3-5). The cropland stream,which had no forest buffer, had a maximumtemperature that was 5 to 13 degrees Celsiuswarmer than the stream flowing through a for-est. Not only did the buffer keep the watertemperature cooler during the summer months,but it kept the stream warmer during the coldestmonths of winter. Studies in southeastern Penn-sylvania have shown that during the summermonths, streams passing through open fields are10 degrees Fahrenheit warmer than streamspassing through forest shade. The streams in theopen fields are usually too warm to support troutall year.

Studies show that temperature minimums duringsummer months are greater for streams with noforest buffer. If the temperature is elevated forprolonged periods of time, there will be an ad-verse impact to the energy budget of the aquaticecosystem. If nearstream vegetation is left toshade the stream, only minor changes in streamtemperature will result. If forested buffers aremaintained adjacent to streams, significant de-creases in water temperature will result. Grassbuffers cannot provide this benefit.

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Research statistics have shown that angular can-opy density (a parameter used to measureshading) is strongly correlated with temperaturecontrol. The width of the buffer is also relatedto the effectiveness of the buffer to regulatestream temperatures. The research recommendsthat canopy density be kept at least at 80 percentcoverage. It concludes that the maximumshading ability is reached within a width of 80feet, with 90 percent of the maximum reachedwithin 55 feet.

Buffer effectiveness in controlling temperatureincreases as stream size decreases. Usually, thesmaller streams have the greatest temperatureproblems; therefore, if temperatures are con-trolled in the upper reaches of the watershed,

temperature problems in larger downstreamchannels will be controlled as well.

Table 3-3 shows the range of some habitat re-quirements for typical fish.

Large Woody Debris as Fish HabitatEnhancementOne of the most important functions of the ri-parian forest buffer is the addition of largewoody debris (LWD) to a stream. LWD is thenatural accumulation of trees, branches and rootwads, at least 10 centimeters (4 inches) in di-ameter, upon which a large number of aquaticorganisms depend. LWD becomes lodged,forming pools that are needed by trout for sur-

Figure 3 - 5. Riparian forests are very important for shading streams and keeping water temperatures lower.As water temperature increases, the stream has less ability to hold oxygen. Oxygen is needed for plants andanimals to survive. A cropland stream with no forest buffer is 5 to 13 degrees Celsius (generally 10 degreesFahrenheit) warmer than a forest stream. (Source: G.F. Greene, 1950. Land Use and Trout Streams, Journalof Soil and Water Conservation.)

Table 3 - 3Habitat Requirements of Major Families of Fish

Family Oxygen Temperature pH Turbidity Tolerance

Carp >0.5 ppm 70-90° F 7.5-9.0 High

Catfish >4.0 ppm 70-90° F 7.5-9.0 High

Sunfish (in-cluding Bass)

>5.0 ppm 73-80° F 7.5-8.5 Low-moderate

Trout >5.0 ppm 50-60° F 6.0-8.0 Low

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vival. LWD in the form of overhanging logs,debris jams, and root wads provides complexcover for fish that is used for hiding frompredators or to stalk prey. LWD provides foodand shelter to micro- and macro-organisms thatare eaten by fish. Lack of LWDresults in lower fish numbers,lower average size, and lowerbiomass for both warmwaterand coldwater fish species.Most LWD debris originateswithin 60 feet of a stream, so itis imperative that the riparianforest is established if fishhabitat is be to maintained.Ideally, streams supporting fishshould have 75 to 200 pieces oflarge woody debris per streammile.

Different types of vegetationplay certain roles in maintaining a healthyaquatic habitat. Both the size and type of vege-tation within the riparian area are important increating a productive and stable environment.Table 3-4 gives benefits of vegetation to aquaticecology.

Management ConsiderationsHow wide should a riparian buffer be to providethese benefits? It depends on the conditions ofthe site, but most experts agree that 50 to 100

feet of natural riparian buffer is ade-quate to protect water quality andimprove stream conditions for fishand other aquatic organisms. A cor-ridor of this width also will providesuitable habitat for many wildlifespecies such as wood ducks, herons,kingfishers, beaver, muskrat, song-birds, pheasants, quail, fox, deer,raccoons, turtles, snakes, salaman-ders, and frogs.

Careful management of stream cor-ridors can make naturally goodhabitat even better. Before designingriparian buffers to enhance theirvalue for wildlife populations, land

managers should consider the following key is-sues:

1. Which wildlife species are of the great-est conservation priority in the region?

2. How important would the corridor be ashabitat for those priority species withinthe region?

Table 3 - 4

Benefits of Vegetation on Aquatic Ecology

VEGETATION BENEFITS

Trees and shrubs overhanging thestream.

• Shade lowers the water temperature, which improvesthe conditions for fish.

• Source of large and fine plant debris.• Source of terrestrial insects that fish eat.

Leaves, branches, and other debrisin the stream.

• Helps create pools and cover.• Provides food source and stable base for many stream

aquatic organisms.

Roots in the stream bank. • Increases bank stability.• Creates overhanging bank cover.

Stems and low-growing vegetationnext to the watercourse.

• Restarts movement of sediment, water, and debrisfloating in flood waters.

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3. Can the buffer be enhanced enough tomeet the minimum area requirements oftarget wildlife species?

Planting certain types of trees and shrubs canenhance some areas. For example, pheasantsfind wild grapes and dogwood highly desirable,and quail find certain types of lespedeza desir-able. The Maryland Department of NaturalResources - Forest Service sells “conservationpackets” of plant materials through the statenursery. These packets can be very useful inriparian buffer enhancement. A variety of treespecies provides a wide array of wildlife food,dens, roosts, and nesting sites. A combination

of tree sizes provides tall, medium, and shorttree heights, with each height serving as specifichabitat for different species of wildlife.

There are many factors to consider whenchoosing plant materials for each Zone of theriparian buffer, depending on the landowner’sobjective and what Zone is being planted. Table3-5 is a partial list of trees, shrubs, and grassesthat could be planted within the riparian area. Itshows how each benefits wildlife. It is impor-tant to select vegetation that may be periodicallysubjected to flooding. Although this list is notall inclusive, it lists several plant species thatcould be used within the riparian area.

Table 3 - 5Plant Species That Grow Well in the Riparian Area and Their Value to Wildlife

Common Name Vegetation Type Wildlife Value

River birch tree good; cavity nesting

Black willow tree high; nesting

American beech tree high

Eastern cottonwood tree low

Green ash tree low

Silver maple tree moderate

Red maple tree high; seeds/browse

Sweetgum tree low

Sycamore tree high; cavity nesters

American hornbeam tree low

Bitternut hickory tree moderate; food

Flowering dogwood tree high; food (birds)

Persimmon tree extremely high;mammals

Boxelder tree low

Baldcypress tree low

Black locust tree low

Pawpaw tree high; fox & opossum

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Common Name Vegetation Type Wildlife Value

American holly tree high; food, cover,nests

Black walnut tree high

Eastern redcedar tree high; food

Yellow-poplar tree low

Sweetbay tree very low

Blackgum or sourgum tree moderate; seeds

Hophornbeam tree moderate

Swamp tupelo tree high

Red bay tree good, food (quail/bluebirds)

Loblolly pine tree moderate

White oak tree high; food (on welldrained sites)

Overcup oak tree high

Swamp chestnut oak tree high

Water oak tree high

Cherrybark oak tree high

Willow oak tree high; mast

Eastern hemlock tree high; nesting

Southern wax myrtle shrub moderate

Common spicebush shrub high; songbirds

Winterberry shrub high; cover & fruit-(birds). Holds berriesin winter.

Pussy willow shrub moderate; cover-(birds) & nectar-(butterflies)

Sweet pepperbush shrub high

Red-osier dogwood shrub high

Silky dogwood shrub high; mammals &songbirds

Witch-hazel shrub moderate

Hackberry tree high

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Common Name Vegetation Type Wildlife Value

Buttonbush shrub moderate; (duck/shorebirds) & nectar(hummingbirds)

Gray dogwood shrub moderate

Hawthorn shrub moderate

American elderberry shrub high; food

Arrowwood viburnum shrub high

Switch grass grass high; cover

Reeds canary grass grass high; cover, drought-tolerant

Little or big blue stem grass high; cover

Eastern gamagrass grass high; cover

Weeping love grass grass high; cover

Indian grass grass high; cover

Coastal panic grass grass high; cover

NOTE: (For use with the three-zone riparian forest buffer system)

1. Zone 1 has the greatest potential for annual inundation of water and the least moisture stress.

2. Zone 2 has the potential for the greatest moisture stress during the summer, because it could be a steep area sub-ject to rapid drying.

3. Zone 3 has the greatest variability, because some plant species have naturally adapted to these areas, and thewidth could vary greatly.

Grasses integrated as part of riparian forestbuffer systems are often used in Zone 3. Thereare many grass species that provide excellenthabitat for birds and other wildlife. Specifi-cally, many of the warm season grasses (Table3-6 on the next page) provide this valuablehabitat in the form of brood rearing cover, nest-ing habitat, and superior winter cover. Thesewarm season grasses grow upright with somebare ground in between, which provides over-head cover for protection, quality nest sites, andfree movement. It also provides more opportu-nities for food searching in between the clumpsby ground feeding wildlife such as quail. It hasbeen documented in Iowa that switch grassplantings dramatically increase nesting success

of both game and song birds. Pheasants built 20percent more nests in switch grass than in or-chard grass and alfalfa combination. Thesewarm season grasses also stand upright undersnow, offering more winter cover. It is also im-portant to note that the management of many ofthese warm season grasses requires prescribedburning every one to three years. Prescribedburns stimulate insect life, which is valuablefood for chicks, and intense seed set.

Spring is the best time to burn, as the warm sea-son grasses first reach an inch of new growth–usually about April 1. This date can vary frommid-March in a warm spring to mid-April in acool spring, and it varies in the Piedmont orCoastal Plain.

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May and June are the preferred planting monthsfor warm season grasses. In Coastal Plain areas,late April is suitable, and some people havegood planting results into the first few days ofJuly in the Piedmont. Minimum planting ratesare given in Table 3-6.

When planning and maintaining a riparian forestbuffer in a suburban area, the following must betaken into consideration:

1. Corridors in the suburban landscape fre-quently are surrounded by commercial,residential, and industrial developments.These habitats harbor species that arepredators to forest dwellers, such as cow-birds, raccoons, and domestic cats.

2. Corridors may already be planted to non-native species, such as Norway maple, thatcan cause the slow deterioration of thevegetation structure and diversity of the for-est ecosystem.

3. The wildlife population in the corridor maydepend on large forest patches for survivalduring some portion of its life cycle.

4. The wildlife population densities are natu-rally low such that they must receiveimmigrants in order to survive in isolatedpatches.

5. The wildlife population cannot move fromforest patch to patch without an intercon-necting forest corridor.

In summary, riparian areas vary considerably insize and vegetation makeup depending on char-acteristics such as gradient, aspect, topography,soil type of stream bottom, water quality, eleva-tion, and plant community. Riparian areas areused by wildlife more than any other type ofhabitat; they are one of the most productivewildlife habitats in many areas of the Chesa-peake Bay Watershed.

Table 3 - 6Minimum Planting Rates for Warm Season Grasses in

Zone 3 of the Riparian Forest Buffer

Grass Species Planting rate (lb/acre)

Switch grass 5*

Big Bluestem 7

Indian grass 7

Coastal Panic grass 8

Weeping Love grass 3**

*lb is in PLS, which means pounds of pure live seed, not bulk. This is especiallyimportant on fluffy seeds and those with low germination.

**Often seed is mixed with other grasses or 5 pounds Korean or Kobe Lespedeza.

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Aesthetics and OutdoorRecreation Functions/Values ofRiparian Forest Buffer Systems

Riparian forests enhance the natural beauty ofstreams within the Chesapeake Bay Watershedby increasing their aesthetic value. A variety oftrees and other green vegetation on the land-scape provides an enjoyable scenic view andstimulates appreciation of the natural environ-ment.

Riparian forests, which include streamside man-agement zones, furnish a variety of recreationalvalues. An important function of riparian for-ests is their use as urban area greenway systemswith linear parks. Greenways, resulting fromestablishing riparian forest buffers, will be par-ticularly advantageous to residents ofChesapeake Bay urban areas experiencing ashortage of green space. Riparian forest buffersoffer urban residents an alternative to cementand concrete and a solace for rest and relaxa-tion. Increased greenspace improves the overallquality of life in both rural and urban areas. Itoffers people a beautiful natural setting in whichto recreate, socialize, and enjoy all forest re-sources.

The Pennsylvania Citizen’s Advisory Councilfound that the Pennsylvania state forest systemis experiencing a dramatic increase in recrea-tional use. With demand for recreation

resources on the rise, riparian forest buffers notonly contribute to natural resource conservationand clean water, but they also enhance existingstate, county, and municipal park and forestsystems within the Chesapeake Bay Watershed.Riparian forest buffer establishment serves asadditional greenspaces offering alternativeplaces for recreational opportunities in theChesapeake Bay Watershed. Both watershedresidents and visitors will benefit from an in-crease in greenspace.

Recreational activities can be a revenue-generating mechanism for the landowner. Fees,especially for hunting privileges, are oftencharged on a per acre basis and are consideredroutine compensation for landowners in theChesapeake Bay Watershed. For example, inVirginia, nearly two-thirds of its citizens overthe age of sixteen participated in wildlife-relatedrecreation spending $1.1 billion annually.

There are two forms of recreational settings thatoccur in riparian areas – developed and dis-persed. Natural resource managers whoestablish riparian forest buffers must considerthe landowner objectives for recreation whendeveloping and implementing a resource plan.

Some developed recreation areas are designedspecifically to attract visitors to riparian areas.Developed recreation areas place more emphasisand reliance on specially improved constructedfacilities to enhance visitor comfort, conven-ience, and safety. These facilities are usuallyconcentrated in areas that have easy access.Developed campgrounds may provide restroomsand showers, paved roads and drive-ups, desig-nated camp sites, tent pads, grills, and picnictables. These areas have a tendency to attractmore people in a concentrated area. Developed

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campgrounds have designated campsites inclose proximity to each other. Many camp-grounds are designed with vegetation leftbetween sites providing natural buffer areas, yetthere is little privacy. Developed lakes and riv-ers feature boat ramps, launches, and fishingpiers. Other examples of developed areas areski resorts and golf courses. Occasionally,highly developed recreational areas featurevisitor centers and contract with concessionairesto sell food and souvenir items. Developed rec-reation facilities are provided by public andprivate entities. Because of the dependence onconstructed facilities, there are increased im-pacts to the surrounding area.

Other riparian areas are more suited to, or maybe restricted to, dispersed recreation. In contrastto developed recreation, dispersed recreationalactivities occur over wide areas in a variety ofnatural settings, such as entire national, state,and private parks and forests. Dispersed recrea-tional activities are more reliant on the use ofnatural resources. Facility development is lim-ited to the extent necessary for visitor safety,resource protection, general information, andinterpretation. As a result, dispersed recreationis less disturbing to the surrounding environ-ment and more conducive to experiences ofsolitude and “getting away from it all.” Accessto and within dispersed recreational areas maybe more difficult than for developed recreationareas. In some dispersed recreation areas, theroads may be low standard, requiring a four-wheel drive vehicle. Trails will be non-existent,or primitive, with little to no maintenance.Signing is minimal or non-existent. Dispersedrecreation areas may be located farther fromurban areas and require more travel to get tothem.

Riparian forest buffers and streamside manage-ment zones are suitable for a wide variety ofrecreational activities. Landowner objectivesdetermine the type of recreation and level ofdevelopment. It is important to keep in mindthat these areas are in close proximity to streamsand may have fragile vegetation growing that isnot resilient to higher impacts. When decidingupon the type of recreational use, consider the

particular environment of the area and planaccordingly. Recreationists should learn andpractice leave-no-trace, low-impact outdoor rec-reation principles in order to help protectriparian areas. Depending on size, location, andnatural features, riparian forest buffers provide abeautiful natural setting for a wide range of out-door recreational activities.

Types of Recreation That Occurin Riparian Forests

Camping and Picnicking

Camping is one of the most popular forms ofoutdoor recreation, whether in a developed ordispersed setting. Campers must be aware oftheir impact, especially on streams, and takesteps to avoid disturbing them. Human wasteand garbage negatively impact water quality.Developed campgrounds are usually intendedfor car-camping and generally require morespace and permanent structures, such asrestroom facilities, tent pads, grills, and picnictables. The addition of these conveniences willcause greater disturbance and impact. In ripar-ian areas, developed campgrounds should belocated on higher, stable ground.

Backpacking is a more rugged and primitiveform of camping, allowing the recreationist toventure into remote forested areas. Backpackerscarry all of their equipment into the forest withthem in specially designed backpacks. Theymust be self-sufficient without relying on con-structed facilities. Backpacking is generally lessdisturbing to forested areas, as long as camperspractice leave-no-trace outdoor principles.

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Riparian forests also provide a peaceful locationin which to enjoy a picnic with friends and fam-ily. Picnicking can be as simple as bringing apicnic basket and a blanket or using designatedpicnic areas that provide tables, restrooms, andgarbage facilities.

Cycling, Motorbiking, and ATVsCycling is another form of outdoor recreationand exercise that can be enjoyed within ripariansettings, on lightly used roads, or on appropri-ately designed trails. Cycling not only providesa convenient form of travel for exploring beauti-ful areas, it also increases the heart rate andtones the lower body. Touring bikes are suitablefor paved road cycling, while mountain andmotorbiking are suitable for more rugged ter-rain. Driving ATVs is an increasingly popularrecreational activity. Mountain biking, motor-biking, and ATV driving are higher-impactrecreational activities that contribute to soil lossand erosion. It is important to find suitable lo-cations designated for these uses in order toavoid excessive disturbance and damage tosoils, vegetation, and streams.

Horseback RidingHorses have become favored recreational ani-mals. Many people enjoy horseback riding ontrails through forests and parks. Riparian forestsprovide an ideal location for a pleasurablehorseback riding experience, either solo or withfamily and friends.

Hunting and FishingBecause of their close proximity to streams anda variety of habitat, riparian forests are ideallocations for hunting, trapping, and fishing.Hunting and fishing are age-old activities, onceundertaken for survival. Today, many peopleenjoy hunting and fishing as recreational activi-ties.

.

They allow particicpants to express an innernatural instinct and to commune with nature onnature’s terms. Some of the wildlife speciesfound in riparian forests include: deer, elk,black bear, wild turkey, grouse, quail, rabbit,squirrel, raccoon, and waterfowl includingducks and geese. Many people enjoy fishing,whether they release the catch or use fish forfood. Riparian forests provide a beautiful andpeaceful access for fishing in streams, ponds,lakes, bays, or along ocean beaches.

RelaxingRelaxing is restorative and pleasurable, provid-ing a respite from hectic schedules and theeveryday pressures of life in an increasinglyfast-paced world. A riparian forested area is awonderful location for rest and relaxation. Indi-viduals who choose riparian areas as a place torelax, enjoy peace, quiet, and nature will be re-charged and ready to take on the world again.The resulting peace of mind can have far-reaching effects on the whole being. Relaxingin nature is constructive as well. Reflection in

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and communing with nature can be inspira-tional, enlightening, and enhancing to thecreative processes. Many successful authorshave written popular books about the positivebenefits and effects of their outdoor experi-ences. Relaxing can be particularly important tourban communities where a riparian forest canprovide recreation and aesthetic values close tohome.

Walking/Hiking/Running/Roller andIn-Line SkatingRiparian areas provide a natural setting for ex-ercising and enjoying the pleasures of aerobicactivities. More people are walking, hiking, andrunning to improve their overall health and well-being and to reduce stress. Participation inaerobic activities within a refreshing riparianarea enhances the emotional and physical bene-fits. The benefits provide incentive for walkers,hikers, and runners to engage in regular exerciseprograms. Roller blading is becoming a morepopular outdoor recreational activity and a goodway to exercise. Skating, an alternative form ofaerobic exercise, enables recreationists to covermore miles than simply walking or running.Riparian areas are a valuable resource in subur-ban and urban areas where the chances foroutdoor recreation are sometimes limited.

Water Recreation (Motor Boating,Sailing, Canoeing, Rafting, Kayaking,and Swimming)More than half of all outdoor recreationalactivities are water-related. This type of recrea-tion ranges from aesthetic appreciation of water,to observation of waterfowl and aquatic life, toactivities occurring in the water. Canoeing,rafting, kayaking, and tubing are increasinglypopular recreational activities, as well as snor-keling and scuba diving. Rafting tends to belargely a commercial venture with outfittersguiding large groups; kayaking is both commer-cial and private. Although some outfitters doguide canoe trips, canoeing is a more solitaryactivity motivated by the desire for solitude anda wilderness experience.

Canoeing, rafting, and kayaking require put-inand take-out areas. These areas can be woodendocks, concrete boat ramps, built-up gravel andsand beds (mini-docks), or a simple grassy areawhere use is funneled. These recreationistsusually camp in primitive, designated campsitesalong the shore. Some put-in and take-out areashave shelters, fire rings, and/or picnic tables touse, depending on the land ownership. Landalong rivers, lakes, and bay shores often has acombination of owners. Canoeists, rafters, andkayakers need to know who owns the land theydesire to use, so they can make appropriate ar-rangements with the landowner(s). Riparianforests provide access to water-based recreationand a beautiful backdrop for engaging in theactivities.

Wildlife Viewing, Birdwatching,Nature Appreciation, EnvironmentalStudy, Wildlife and Nature Photo-graphy, Collecting for Arts and CraftsRiparian forests are a natural laboratory for na-ture appreciation and environmental studies.Many people enjoy studying and collectingshells and rocks dispersed along river banks andlake and bay shores. Wildlife, birds, and water-fowl are interesting to observe in their naturalsettings.

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Many people enjoy photographing wildlife as ahobby or for their professional livelihood. Theoutdoors also stimulates creative expression inwriting, drawing, painting, arts, and crafts. Ri-parian forests are a good place to find naturalmaterials used in many art and craft projects.Seeds, nuts, shells, leaves, cones, needles, fi-bers, plants, woods, and flowers are used tomake wreaths, terrariums, birdhouses, and othercrafts. These are made for personal enjoyment,gifts, and displays, or for arts and crafts busi-nesses.

Winter Recreation (Snowmobiling,Cross-Country Skiing, Ice Skating,and Snow Shoeing)Many recreationists enjoy the exhilaration ofwinter sport activities. Cross-country skiing, iceskating, and snow shoeing are relatively low-impact activities that provide opportunities forsolitude and exercise. Snowmobiling is ahigher-impact, adventuresome, and social-orientated activity. Riparian forests provideanother resource for the enjoyment of winterrecreation.

The above mentioned outdoor recreational ac-tivities can be pursued and enjoyed withinriparian forest buffers or streamside manage-ment zones. Riparian forest buffers protect andenhance streams and increase the opportunitiesfor recreational pursuits in the Chesapeake BayWatershed.

ReferencesAllan, J.D. and A.S. Flecker. 1993. Biodiver-sity conservation in running waters. BioScience43:32-43.

Capel, S. 1992. Warm season grasses for Vir-ginia and North Carolina - benefits for livestockand wildlife. Virginia Division of Game andInland Fisheries.

Chesapeake Bay Program. 1994. Riparian for-est buffers: restoring and managing a vitalChesapeake resource. Conference proceedings–Riparian Forest Buffers, Chesapeake Bay Pro-

gram Office; October 5-6, 1994; Ellicott City,MD.

Citizens Advisory Council to the Department ofNatural Resources. 1992. These woods areours. A Report on Pennsylvania’s State ForestSystem. Harrisburg, PA.

DeGraaf, R.M., M. Yamasaki, W.B. Leak, andJ.W. Lanier. 1992. New England wildlife:management of forested habitats. Gen. Tech.Report NE-144. USDA Forest Service, North-eastern Forest Experiment Station.

Dissmeyer, G. and B. Foster. 1986. Somepositive economics of protecting water qualityfor fish. Presentation at SAF National Conven-tion in Birmingham, AL.

Gregory, S.V., F.J. Swanson, W.A. McKee, andK.W. Cummins. 1991. An ecosystem perspec-tive of riparian zones. BioScience 41:540-551.

Groffman, P.M. 1994. Denitrification in fresh-water wetlands. p. 15-35, In Current Topics inWetland Biogeochemistry. Wetland Biogeo-chemistry Institute, Louisiana St. Univ., BatonRouge, LA.

Hammitt, W.E. and D.N. Cole. 1987. Wildlandrecreation. New York, NY: John Wiley &Sons.

Jacobs, T.C. and J.W. Gilliam. 1985. Riparianlosses of nitrate from agricultural drainage wa-ters. J. Environ. Qual. 14:472-478.

Jayne, P. and R. Tjaden. 1992. Field bordermanagement. University of Maryland Coopera-tive Extension Service. Fact Sheet #600.

Jordan, T.E., D.L. Correll, and D.E. Weller.1993. Nutrient interception by a riparian forestreceiving inputs from adjacent cropland. J. En-viron. Qual. 22:467-473.

Karr, J.R. and I.J. Schlosser. 1978. Water re-sources and the land-water interface. Science01:229-234.

Kraus, R. 1994. Leisure in a changing Amer-ica. New York, NY: Macmillan CollegePublishing Company.

Section III

3-39

Kroll, J.C. 1994. A practical guide to produc-ing and harvesting white-tailed deer. 3rd ed.Institute for White-tailed Deer Management andResearch. Stephen F. Austin State University,Nachogdoches, TX.

Lowrance, R., L.S. Altier, J.D. Newbold, R.R.Schnabel, P.M. Groffman, J.M. Denver, D.L.Correll, J.W. Gilliam, J.L. Robinson, R.B.Brinsfield, K.W. Staver, W. Lucas, and A.H.Todd. 1995. Water quality functions of riparianforest buffer systems in the Chesapeake Baywatershed. EPA 903-R-95-004. CBP/TRS134/95. Annapolis, MD. 67pp.

Lowrance, R.R., R.L. Todd, J. Fail, Jr., O. Hen-drickson, Jr., R. Leonard, and L. Asmussen.1984. Riparian forests as nutrient filters in agri-cultural watersheds. BioScience 34:374-377.

Lusk, A. no date. Getting around in ruralAmerica: trails. In: Proceedings of a NationalPolicy Symposium. Enhancing Rural Econo-mies Through Amenity Resources. Penn StateUniversity.

Maclean, J.R., J.A. Peterson, and W.D. Martin.1985. Recreation and leisure: the changingscene. 4th ed. New York, NY: MacmillanPublishing Company.

Martin, A.C., H.S. Zim, and A.L. Nelson. 1951.American wildlife and plants: a guide to wild-life food habits. Dover Publications, NY.

Missouri Conservation Commission. 1985.Trees along streams.

Morse, D.H. Ecological aspects of some mixedspecies foraging flocks of birds. EcologyMonogram, 40(1):119-168 (1970).

Newbold, J.D., D.C. Erman, and K.B. Roby.1980. Effects of logging on macroinvertebratesin streams with and without buffer strips. Can.J. of Fish. and Aquatic Sci. 37:1076-1085.

Pais, R. 1994. Wildlife corridors in the subur-ban environment. Conference Proceedings -Riparian Forest Buffers, Chesapeake Bay Pro-gram; October 5-6, 1994; Ellicott City, MD.

Peterjohn, W.T. and D.L. Correll. 1984. Nutri-ent dynamics in an agricultural watershed:

Observations on the role of a riparian forest.Ecology 65:1466-1475.

Petit, L. 1994. Planning forest buffers withwildlife in mind. Conference Proceedings - Ri-parian Forest Buffers, Chesapeake BayProgram; October 5-6, 1994; Ellicott City, MD.

Phillips, P.J., J.M. Denver, R.J. Shedlock, P.A.Hamilton. 1993. Effect of forested wetlands onnitrate concentrations in ground water and sur-face water on the Delmarva Peninsula.Wetlands 13:75-83.

Rader, T. 1975. Fish and forests. PennsylvaniaForest Resources - No. 26. December.

Schueler, T. 1995. The architecture of urbanstream buffers. Watershed Protection Tech-niques. Center For Watershed Protection. Vol.1, No. 4, Summer.

Smith, S. and R. Tjaden. 1993. Songbirds: lifehistory and management. University of Mary-land Cooperative Extension Service. Fact Sheet# 613.

Southwick, C.H. 1976. Ecology and the qualityof our environments. D. Van Nostrand Com-pany, NY.

Stoddard, C.H. 1978. Essentials of forestrypractice. John Wiley and Sons, NY.

Sweeney, B. 1994. Ecology of forested streamsin the Chesapeake Bay watershed. ConferenceProceedings - Riparian Forest Buffers, Chesa-peake Bay Program Office; October 5-6, 1994.Ellicott City, MD.

Sweeney, B. 1993. Effects of stream sidevegetation on macroinvertebrate communities ofWhite Clay Creek in eastern North America.Proceedings of the Academy of Natural Sci-ences of Philadelphia, 144: 291-340.

Sweeney, B.W. 1992. Streamside forests andthe physical, chemical, and trophic characteris-tics of Piedmont streams in Eastern NorthAmerica. Water Sci. Tech. 26:2653-2673.

Tjaden, R. 1991-92. Eastern cottontail rabbits;bobwhite quail; ring-necked pheasants; ruffedgrouse; eastern wild turkeys. University of

Section III

3-40

Maryland Cooperative Extension. Fact Sheets #601-604 & 606.

Tjaden, R. 1991-92. Introduction to wildlifehabitat. University of Maryland CooperativeExtension. Fact Sheet # 597.

Trial, L. 1992. Life within the water. Conser-vation Commission of the State of Missouri.

University of Maine Cooperative ExtensionService. 1988. A forester’s guide to managing

wildlife habitats in Maine. University of Maineat Orono.

USDA-Soil Conservation Service and MissouriDepartment of Conservation. 1985. Streamcorridor management. December.

Wade, R. 1992. Planting crops for wildlife.University of Maryland Cooperative Extension.Fact Sheet #598.

Wilson, E.O. 1988. Biodiversity. NationalAcademy Press, Washington, DC.