Module 8. The Eastern Deciduous Forest Where are the Deciduous Forests? Humans in the Forest Forest Ecosystems Resources Structure & Function Succession The Nitrogen Cycle Role in the Carbon & Hydrologic Cycles Resource Problems in the Forest Introduced Species (role of biodiversity) Air Pollution & the N Cycle Logging & Mining Trends and Outlook Management & Restoration in the Forest

Terrestrial Biomes of North America Patterns driven by atmospheric circulation & geography

green = low chlorophyll = low productivity

red = high chlorophyll = high productivity

concepts: • resource availability is controlled by weather and landscape • vegetation zones mirror these resources • forests provide numerous human benefits

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Eastern Deciduous Forest Resources influence ecosystem structure beech, birch, maple

Bailey’s Hot Continental & Hot Continental Regime Mountain Divisions

oak, hickory, buckeye

poplar, oak, maple

concepts: • ecosystem type reflects patterns of resource availability (water & temperature) best suited for the growth, survival, and reproduction of deciduous tree species

Forest Ecosystems Communities vary with abiotic factors in the environment

Douglas fir - lodgepole pine Rocky Mountain Forest Alder riparian forest, CA

Oak savanna, WI

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Variation in the Eastern Forest Forest type reflects variation in topography

Mixed Deciduous Oaks Beech-Maple Spruce-Fir Adapted from Hicks (1998)

Microclimate & Species Composition Resource variation creates diversity in the landscape oak poplar maple maple sycamore

spruce fir pine

oak poplar maple

concepts: • topography & elevation influence water & temperature regimes • resource variation controls forest tree species composition

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The Forest Today Reflects human disturbance of the ecosystem

original forest community

agriculture & predator suppression

clear-cut 1800-1920

wild fires

chestnut blight, 1905

gypsy moth, 1869

development & selective cutting

The Depression

today’s forest community

regeneration

potential organisms

resulting community

concepts: • biological & management factors impact regeneration • social & economic circumstances further influence the forest

Forest Succession Changes in species composition with time

time community

1-10 old field

10-25 shrubs

25-100 pine forest

100+ hardwood forest

concepts: • organisms change the environment, altering resource availability • as resources changes, new species exploit them • over time, there is a gradual shift in species composition

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Mount St. Helens Catastrophic disturbance of terrestrial and aquatic ecosystems

Mount St. Helens erupted on May 18, 1980. The eruption killed trees as far away as 19 miles and devastated lakes in the blast zone.

Mount St. Helens

Lake Obscurity

Mount St. Helens Ecosystem recovery

Fireweed re-appeared as early as the summer of 1980 and many small trees and plants were protected by snowpack. Seeds, carried by wind and animals, entered the area and grew. Aquatic systems also recovered rapidly.

ublib.buffalo.edu/.../units/sel/ exhibits/msh/mshimage.html

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Biogeochemical Cycles Cycle nutrients through the environment

reservoir in the environment

plant-available pool

primary producers

consumers

decomposers

geochemical cycling

biological cycling

Temperate Forests Play a critical role in carbon cycling

As forests grow, fixed carbon is stored in biomass & in soils CO2 fluxes fixed C fluxes

concepts: • ecosystem pools of carbon: atmosphere, biomass, soils • carbon added through photosynthesis, growth, & litter • carbon lost through respiration and cycling - “decomposition”

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Temperate Forests Influence the hydrologic cycle

Transpiration absorbs energy, cools & adds H2O to the atmosphere

Canopies break the fall of water, protect soil, foster infiltration Litter facilitates infiltration

evapotranspiration precipitation

Roots hold soils together, reduce erosion

concepts: • ecosystem pools of water: atmosphere, biomass, soils • water added through precipitation, lost through evapotranspiration • canopies alter energy in raindrops & atmosphere

The Nitrogen Cycle Processing of N within a community herbivores

carnivores

N2 denitrification

N fixation NH4+ , NO3-

microbes

decomposers

concepts: • autotrophs & some heterotrophs capture & “fix” nitrogen • heterotrophs rely on this conversion of N to useful forms • matter is conserved in ecosystems

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