Forest Ecology - UCANR
Transcript of Forest Ecology - UCANR
Forest Ecology (Forest Distribution, Forest Change, and Forest Mgt)
Ryan DeSantis
University of California Cooperative Extension
• What is a “natural landscape”?
1990
1880
Swift River Valley (Western MA)
Forest land percent of total land: Maine 89% New Hampshire 85% Vermont 78% Massachusetts 63%
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Today’s forest is a result of:
• Previous human management
• “Natural” disturbance*
• Genetics
• Seed dispersal strategies • Seed size, shape, abundance
• Competition*
• Soils
• Geology
• Slope/aspect
• Climate*
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H
W
TC
Annual precipitation – H-Hayfork, W-Weaverville, TC-Trinity Center http://library.humboldt.edu/~rls/geospatial/nwcalmaps.htm
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California
Location, location, location
32 to 42o north/south latitude (Mediterranean, Australia, New Zealand, S. Africa)
Mediterranean climate – cool, wet winters and warm, dry summers
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West <<< >>> East
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• Riparian – Communities adjacent to water
– Big leaf maple, black cottonwood, dogwood, white alder, willow
– Important for terrestrial and aquatic wildlife
• Oak woodland – Xeric environment
– Associated with grass
– Adapted to frequent low-intensity fire
• Montane chaparral – Most extensive CA vegetation type
– Manzanita, ceanothus
– Wildfire important
– Drought resistant
Our local forest types
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• Mixed conifer – Middle elevations of Klamath-Cascade (3,000-6,000 ft)
– Greatest conifer diversity in the world
– Ponderosa pine, Jeffrey pine, sugar pine, incense cedar, white fir,
Douglas-fir, black oak, manzanita, ceanothus, bitter cherry, mountain
misery
– Periodic fires
– Some snow
– 20th Century fire suppression changed forest density and composition
• Douglas-fir-mixed evergreen – Douglas-fir dominant throughout much of Pacific Northwest
– Associated with mixed evergreen hardwood species including
California bay, coast live oak, canyon live oak, tanoak, Pacific madrone
– Adapted to frequent low-intensity fire
Our local forest types
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• True fir
– Found along higher elevations in the Klamath-Cascade, between
mixed conifer and subalpine forests (6,000-8,000 ft)
– Heavy snowfall
– White fir, Jeffrey pine, lodgepole pine, juniper
• Subalpine
– Found at highest elevations of the Klamath-Cascade, just below
timberline (8,000-11,000 ft)
– Whitebark pine, mountain hemlock, lodgepole pine, juniper
Our local forest types
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Tree species differ in their adaptation to:
Shade
Frost
Temperature
Drought
Fire
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Shade tolerance – most to least tolerant
white fir
red fir Douglas-fir
sugar pine incense cedar
ponderosa, jeffrey pine black oak
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ASPECT
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Frost tolerance (seedlings) – most to least
lodgepole, w. white pine
red fir ponderosa, jeffrey pine
incense cedar sugar pine
white fir Douglas-fir
madrone
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Temperature adaptation – warm to cold
ponderosa pine, black
oak, madrone Douglas-fir, sugar pine, incense
cedar, bigleaf maple red fir, lodgepole pine
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Ponderosa pine 2000 ft
Ponderosa pine 3000 ft
Ponderosa pine 3500 ft
Latitude
40o
38o
36o 16
Drought tolerance – least to most tolerant
red fir
white fir
sugar pine
Douglas-fir
lodgepole pine
incense cedar
ponderosa pine
jeffrey pine
black oak 17
Fire resistance –bark thickness, resin content, foliage flammability. Increasing resistance.
lodgepole pine
incense cedar, western white pine
sugar pine, white fir
Douglas-fir, ponderosa pine
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Ponderosa pine
Lodgepole pine
Knobcone pine, California
Jack pine, Minnesota
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Drastic changes to forest ecosystems: knobcone pine and jack pine require large, stand-replacing fires for regeneration
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Forest change
Changes to ecosystems occur due to….
• Displacement
• Site alteration
• Colonization
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Forest change
How fast does change occur? Depends on…
• How much change must occur
• Productivity of organisms
• Longevity of organisms
• Degree of dominance of site by seral stage
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Forest change
Ecological succession: Temporal changes in types, numbers and groupings of organisms occupying an area and concomitant changes in the physical environment
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Ecological succession
• Primary – following catastrophe, start with physical abiotic environment, no biological legacy, e.g. island building in ocean, retreating glacier, volcanic eruption
• Secondary – follows disturbance that leaves a significant biological legacy, e.g. fire, windstorm, clearcut
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Successional gradients
Light or shade: high low
Water: xeric mesic
Nutrients: low high
Species diversity: low intermediate high 25
Pioneer species: bare/exposed areas (ponderosa pine)
Gap-phase species: under closed canopies and later released by opening of a gap (redwood)
Seedling establishment
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Stages of succession
• Pioneer
• Consolidation
• Subclimax
• Climax
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Competition
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Suppressed seedling Released seedling 30
Diameter growth with competition control. 9 yrs.
Diameter growth slows with increasing competition. 23 yrs
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17 rings
17 rings
Effect of thinning, competition reduction
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How did your forest develop?
Use tips such as:
• Current overstory & regeneration
• Stumps
• Dead trees (oak, manzanita, etc.)
• “Wolfy” (dead, large, understory) limbs
• Fences
• Understory vegetation (grass? woody plants?)
• One or many ages, one or multiple species
• Opening size
• Fire scars
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Disturbances
• Fragmentation
• Weather (wind, drought, hail, flood, ice/snow)
• Fire
• Alteration of fire regime
• Diseases
• Invasive insects
• Invasive plants
• Global climate change
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Natural disturbances: wind damage
Forest before… ...and after wind damage
Lee Frelich Roy Rich
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Natural disturbances: wind damage
Affects….
• Energy capture, transfer and storage
• Biogeochemical cycles
• Light, temperature, water
• Soil
• Species>Population>Community>Ecosystem
Disturbance
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Natural disturbances: insect damage
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Natural disturbances: insect damage
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• Photosynthesis:
CO2 + H2O + energy cellulose + O2
• Fire:
O2 + cellulose + energy CO2 + H2O + energy
• Similar to organic matter decomposition, but much faster.
Fire= photosynthesis in reverse
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• Cool/wet Winters grow fuels, warm/dry Summers fuel annual fire season
Mediterranean Climate
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California’s Mediterranean Climate
30%+ of U.S. national wildland fire management
expenditures
• Cool/wet Winters grow fuels • Warm/dry Summers fuel annual fire season
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Fire Climate - Precipitation Patterns
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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NORTH PLATTE, NE
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FLAGSTAFF, AZ
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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YELLOWSTONE LAKE, WY
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REDDING, CA
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Three parts of the fire triangle
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Fuel (something that will burn)
CA: historically, fires maintained a variety of vegetation types
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Affects energy, competition, succession… + & -
• Fire
• Wind
• Drought
• Ice
• Insects and disease
• Anthropogenic (forest management) – Harvesting trees, shrubs, other forest products
– Clearing space for trails, houses, agriculture
– Prescribed burning, thinning, etc. to control brush, fire hazard, wildlife habitat
Disturbance
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Forest management affects energy in the forest
• Pest control
• Clearcutting
• Site preparation
– Preparing site to promote future forest
• Prescribed burning
• Fertilization
All related to natural disturbances…
Energy capture, transfer and storage
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Ryan DeSantis Forestry Advisor UC Cooperative Extension Trinity, Shasta, and Siskiyou Counties (530) 224-4900 [email protected]
UC Cooperative Extension in… Trinity County: http://cetrinity.ucanr.edu/ Shasta County: http://ceshasta.ucanr.edu/ Siskiyou County: http://cesiskiyou.ucanr.edu/