No Slide Title - University of Maryland Extension...Principles of Forest Ecology • Site Quality...
Transcript of No Slide Title - University of Maryland Extension...Principles of Forest Ecology • Site Quality...
Principles of Forest Ecology and Management or…
“Forensic Forestry”
Reading the Land
Jonathan Kays University of Maryland Extension
Where Do We Start?
Think Like A Plant
Act Like A Plant
Thinking and Acting Like a Plant
• What is your favorite plant? – Where does it grow? – How do you describe that place? – What is important?
What Does a Plant Need?
• Light • Water • Nutrients
Principles of Forest Ecology
• Site Quality • Shade Tolerance • Forest Succession • Plant Competition • Stand Development • Role of Fire, Insect & Disease, and Herbivory,
Site The environment or system supporting a
forest, which influences trees and plants growing there.
The sum of Soil, Topography, Climate,
Plants, and Animals
Forest Succession on a Site Predictable changes in plant communities
as the competing organisms respond to and modify the environment. These changes will vary depending on the site.
Site is More Important than the Vegetation
• It is more fixed • It is more stable • It is more easily defined • Reflects disturbance
– Strip mine (extreme) – Pasture (subtle) – Harvesting (either)
• Look for Clues!
Maryland Physiographic Regions or “Sites”
Coastal Plain Ridge& Valley
Appalachian
Plateau Piedmont
Great Valley Blue Ridge
Dominant Forest Communities
Garrett County – Alleghany Plateau
Allegany County - Ridge and Valley
Piedmont Region
Coastal Plain – Southern Maryland
Coastal Plain - Eastern Shore
Forest Soils – Foundation of Site Quality “Healthiest Soils in the World”
Soil profile How does soil develop or form? From the bottom or the top? Where is the older soil?
Plow Layer
Root Mat that holds soil in place
Wetland soils contain organic material, exist with little oxygen, and have developed specialized
ecosystems compared to upland areas.
Consider soils when selecting tree species to plant. Is soil well-drained or poorly drained? Black walnut
does poor in wet areas.
Where are most of the tree roots?
Most tree roots are found within the top 12 inches of soil
Online Soil Survey http://websoilsurvey.nrcs.usda.gov/app/
The old way..
You are here!
Mineral Cycling
• Pine forest – slow turn around • Hardwood forest – faster turnaround
Faster recycling of nutrients in hardwood
forests compared to pine. WHY?
Best Management Practices protects
the root mat
Slope Position
Are trees larger on the upper or lower slope?
Climate, soil, available water, and nutrients all affect how well a tree grows. If minimum requirements are
not met, a tree may not grow in a given area.
Oaks are better adapted to dry and shallow hilltop soils, while yellow-poplar trees are
found on more fertile lower slopes
Poor Site Good Site
Certain trees adapt to special conditions
Site Indicator Species
Aspect Direction the slope is facing
south
west east
north
A B
Solar Radiation What would the line look like for a
south, north, and east facing slope?
6 a.m. Noon 6 p.m
Effect of Aspect on Site Quality
South-facing Slope North-facing
Slope
Quantity of biomass produced from an acre of woodland depends upon the site quality and is similar to farm crops.
Principles of Forest Ecology
• Site Quality • Shade Tolerance • Forest Succession • Plant Competition • Stand Development • Role of Fire, Insect & Disease, and Herbivory,
Shade Tolerance is the ability of a plant to grow in the shade
• Intolerant Species - intolerant of shade and must have full sunlight to grow
• Tolerant Species - tolerant of shade – does not require full sunlight to grow
• Intermediate tolerance - can grow in partial sunlight or shade
Tolerance, Sunlight, Growth
0% 50% 100% Percentage Sunlight
D B H
Intermediate tolerance – trees that can establish themselves in the understory, but require full
sunlight to mature -- Oak in this example
Tolerance of Common Forest Trees
Intolerant Intermediate TolerantFull Sun Full ShadeVirginia pine White pine Hemlock
Loblolly pine Hickories Beech
Yellow-poplar Yellow & bl birch Sugar maple
Scarlet & black oak White & red oak Red maple
Black walnut Chestnut oak Silver maple
Green ash Red oak Basswood
Red cedar White ash American holly
Grey birch
Principles of Forest Ecology
• Site Quality • Shade Tolerance • Forest Succession • Plant Competition • Stand Development • Role of Fire, Insect & Disease, and Herbivory,
Forest Succession Predictable changes in plant communities as
the competing organisms respond to and modify the environment.
Principle: All natural areas change over time,
whether or not you do anything to them.
Five Stages of Secondary Forest Succession
Stage 1 Herbaceous species
Stage 2 - Old Field
Stage 2 - Old Field of red cedar and goldenrod. It may be beneficial to maintain old field habitats by cutting down invading trees, which can
maintain a diversity of habitats on the property.
Invasive and natural species can take over
Honeysuckle
Kudzu
Grapevine
Old field red cedar being overtopped by shade intolerant tree species (yellow-poplar in this case).
Stage 3 Tree crowns close, sunlight disappears, resulting in dieback of ground vegetation. Poor wildlife value for this stage of succession.
Stage 4
Stage 5 Old Growth
Early Successional Species Vary by Region
Forest succession is the progression of plant communities that begins with shade intolerant plants and ends up with shade tolerant plants.
Virginia Pine early successional forest common on poor soils.
Example of an early successional Virginia pine forest that is dying. Beech trees (a late successional species) have established themselves in the understory and will form the new forest.
Tree Planting--Pushing succession ahead
Forest Harvesting:
Effect on Succession?
Important Role of Native Species
• Native plants and insects have developed evolutionary relationships. Caterpillars & insects provide protein sources for birds and mammals.
0
10
20
30
40
50
60
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Native Woody Non-Native Woody
Num
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f lep
idop
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n sp
ecie
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Forest succession & wildlife habitat
Principles of Forest Ecology
• Site Quality • Shade Tolerance • Forest Succession • Plant Competition • Stand Development • Role of Fire, Insect & Disease, and Herbivory,
What Do Plants Compete For?
• Light • Water • Nutrients
Are these trees different ages?
Is tree size a reliable indicator of tree age? Why?
Tree is a factory ... Leaves use sun and
water to produce food...
More leaves… More food… More diameter growth...
The dominance of a tree refers to the position of its crown relative to other trees in the canopy. In even-aged forests, the
more dominant trees have won the competition for light.
Forest Thinning - improve growth & species composition, not regeneration
25 years
25 years
- More leaves… - More food… - More diameter growth...
Leaves use sun and water to
produce food...
Live crown ratio (LCR) is the ratio of the foliage canopy to the total height of the tree. - Hardwood – 5065% - Pine 70-90%
Epicormic Branching
As buds under bark are exposed to sunlight, they grow and form new branches on the tree bole and can reduce quality. Do not open the forest canopy too much.
Leaving the proper stocking produces better growth and little
epicormic branching.
Picture: woodland after a sustainable
harvest.
Unsustainable harvest removed dominant and best trees and left the rest. They go by the names of diameter-limit cutting, selection harvest and high-grading.
This amounts to starting over.
Principles of Forest Ecology
• Site Quality • Shade Tolerance • Forest Succession • Plant Competition • Stand Development • Role of Fire, Insect & Disease, and Herbivory,
Regeneration is the key: Different species have different regeneration strategies
Some species like yellow-poplar, ash and maple need bare soil to germinate seeds…
Heavy seeded species: * Oak * Hickory * Walnut
Slow and steady…
Stump sprouts from cut hardwood stumps are the most vigorous source of hardwood forest regeneration.
Stump sprouting reduces with stump diameter
If stumps are cut low, sprouts from the root collar will grow into quality trees (right).
Stand Development: Tree Density increases over time Year 1: 10,000 stems/ac Year 15: 1,000 stems/ac
Volume Growth Per Tree or Acre is Controlled by Tree Density (or Stocking)!
Well spaced trees optimize volume growth
Basal area is the sum of the cross-sectional area of tree stems 4.5 feet above the ground
We measure the density or stocking of the forest using basal area?
BA in a Few Big Trees or Many Smaller Trees
Development of vertical stratification as trees die,
holes are filled, others seed in.
Stand Development • A function primarily of
– site quality – Past history – current practices (grazing, for example) – species composition
A photographic history from the Allegheny Plateau in Pennsylvania
(1927-1998)
1927
1928
1937
1947
1958
1968
1978
1998
Forests are resilient
60 years later
Principles of Forest Ecology
• Site Quality • Shade Tolerance • Forest Succession • Plant Competition • Stand Development • Role of Fire, Insect & Disease, and Herbivory,
Smokey Bear Changed the Landscape…
• Fewer low intensity fires • Buildup of fuel in understory –
larger crown fires result • Oak-hickory species lost
ecological advantage
Fire releases nutrients, renews,
and favors certain
tree species
Fire ecology differs by region Apples ‘n oranges
Chestnut Blight changed the forest in the span of a few years in the late 1920’s.
Gypsy moths continue to be a
periodic problem.
Emerald Ash Borer will kill all ash trees
Major disturbances, such as hurricanes, tornadoes, and
wind storms.
Other Disturbances
Invasive species
Deer browsing
Southern pine beetle
• No seedling regeneration in the majority of understory plots – Prettyboy….. 84% – Liberty…….. 74% – Loch Raven.. 63%
City of Baltimore, Reservoir Forests Example: intense deer browse leads to the disruption of ecological processes
Deer overabundance negatively impacts forest regeneration and wildlife habitat for other species. Forest birds that used to
be next in the ground vegetation are no longer found.
Principles of Forest Ecology
• Site Quality • Shade Tolerance • Forest Succession • Plant Competition • Stand Development • Role of Fire, Insect & Disease, and Herbivory,
How do we put all this together to make recommendations for management activities?
What History Are
You Writing?