FOREST ECOLOGY Rapid River Schools “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? Rapid River Schools 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 Rapid River Schools COMPOSITION STRUCTURE FUNCTION COMPOSITION Rapid River Schools Genetic Diversity - Gene Pools Species, Number of Species & Species Abundance Populations of Animals & Plants Species Associations & Community Diversity Ecosystem Diversity STRUCTURE Rapid River Schools 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 Rapid River Schools 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. Rapid River Schools 40% 80% 100% Adapted from Baughman, et al., 1993. Woodland Stewardship. P. 20. EDGES, SNAGS, AND FRAGMENTATION Rapid River Schools Edge Effect Forest Fragmentation Large Snags Green. 1995. Birds and Forests. P.55. UM-Cartography Lab. FUNCTION Rapid River Schools Energy Capture & Trophics Weathering Mineral & Nutrient Cycling Water Movement Temperature & Humidity Succession & Disturbance ENERGY CAPTURE Rapid River Schools Energy Capture 10% Trophic Levels CYCLING Ecosystem Rapid River Schools Gains Losses Nutrient, Mineral, and Water Cycling SUCCESSION Rapid River Schools Grasses & Forbs Shrubs & Saplings Young Forest Mature Old Forest Forest Wisconsin DNR, 1995. Wisconsin’s Biodiversity as a Management Issue. P. 22. DISTURBANCE Rapid River Schools 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 Rapid River Schools 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 Rapid River Schools 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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