Download Module 8. The Eastern Deciduous Forest Terrestrial Biomes of North

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
Biology 105 Module 8a
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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
Biology 105 Module 8a
WV deciduous forest
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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
Biology 105 Module 8a
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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
Biology 105 Module 8a
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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
Biology 105 Module 8a
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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”
Biology 105 Module 8a
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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
Biology 105 Module 8a
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