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					FOREST ECOLOGY

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“Conservation is a state of harmony between men and land.”
“A Sand County Almanac” Aldo Leopold - 1949

WHAT IS A FOREST?
Only trees? A community? An ecosystem? Includes animals? Fish? Streams & lakes? Houses? How big of an area?

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Regeneration areas? Plantations? Christmas tree farm? Ecological processes like nutrient or energy cycling?

“That portion of a geographically large area dominated by trees. As an ecosystem, it is meant to include all plants and sometimes the animals dependent upon the trees and plants. Smaller area of largely homogenous tree compositions are called stands”.

FOREST ECOLOGY BASICS

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COMPOSITION STRUCTURE FUNCTION

COMPOSITION

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Genetic Diversity - Gene Pools Species, Number of Species & Species Abundance Populations of Animals & Plants Species Associations & Community Diversity
Ecosystem Diversity

STRUCTURE

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Vertical & Horizontal Spatial Heterogeneity & Density Edge Effect Islands & Fragmentation
Dead Trees & Snags

Micro-Environments
Appearance

VERTICAL STRUCTURE
Vertical structure refers to the “ladder-like” arrangement in a forest.
Dominant

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Co-Dominant

Co-Dominant
Intermediate

Intermediate

Shrubs

Suppressed Ground Cover

Adapted from Baughman, et al., 1993. Woodland Stewardship. P. 17.

HORIZONTAL STRUCTURE
Stand density and crown cover within timber stands and across the landscape is horizontal structure.

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40%

80%

100%

Adapted from Baughman, et al., 1993. Woodland Stewardship. P. 20.

EDGES, SNAGS, AND FRAGMENTATION

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Edge Effect

Forest Fragmentation

Large Snags
Green. 1995. Birds and Forests. P.55. UM-Cartography Lab.

FUNCTION

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Energy Capture & Trophics
Weathering

Mineral & Nutrient Cycling
Water Movement

Temperature & Humidity Succession & Disturbance

ENERGY CAPTURE

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Energy Capture

10%

Trophic Levels

CYCLING Ecosystem

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Gains

Losses

Nutrient, Mineral, and Water Cycling

SUCCESSION

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Grasses & Forbs

Shrubs & Saplings

Young Forest

Mature Old Forest Forest

Wisconsin DNR, 1995. Wisconsin’s Biodiversity as a Management Issue. P. 22.

DISTURBANCE

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Forested ecosystems are dependent upon disturbance for renewal and to provide biological diversity. The plants and animals in a forest don’t know whether the disturbance is caused by natural events or human-caused events. Natural Events Fire Wind Animals Flooding Diseases/Insects Human-Caused Events Fire Harvest Pollution Development Exotic Introductions

FORESTRY AND WILDLIFE

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Woodland wildlife is managed by manipulating the forest to provide the kind and variety of habitat needed. Forestry practices in the U.P. have many effects:

• encourages plant diversity • encourages forest regeneration
• causes multiple age distributions • provides “edge” • creates horizontal and vertical structure • adds more micro-environments • accelerates system metabolism & nutrient cycling

IDEAS FOR YOUR LAND

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In most parts of the country, forest is a small part of the landscape. In the U.P., forest is the dominant cover type. This causes resource managers to rearrange priorities for habitat management that differ from the general opinion.

1. Modify timber harvests (time & space).
2. Leave large snags & large fallen logs. 3. “Create” future tree cavities. 4. Construct brush piles. 5. Mix areas of varying vertical structure.

6. Create small openings.


				
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