5.2 clear-cutting apes

direct effects?

soil erosion, increased soil & stream temp, flooding and landslides

soil erosion effects

caused by loss of stabilizing root structure

removes soil organic matter & nutrients from forest=causes unhealthy stream

deposits sediments in local streams

• warms water and makes it more turbid

clear cutting

cut everything, leads to muddy streams

selective cutting

cuts only a few trees, leads to clear stream

increased soil and stream temp effects

loss of tree shade = inc in soil temp = move absorption of energy into soil & water

• soil has lower albedo than leaves of trees, organisms’ range of tolerance changes

loss of tree shade - inc in river/stream temp

erosion of sediments into rivers = inc temp

flooding and landslides

logging machinery compacts soil = harder for water to infiltrate = water moves faster

increased sunlight dries out soil

loss of root structure = erosion of topsoil & O horizon → landslides

• all factors decrease H2O holding capacity of soil causing flooding and landslides

tree plantations

areas where the same tree species are repeatedly grown and harvested

what are the effects of tree plantations

lowers biodiversity, all the same age

lowers biodiversity effects

biodiverse, mature forests are replaced w single species forests

less species diversity = lower resilience

less habitat diversity for other organsims

all the same age effects

all trees planted same time = all trees the same age

loweres biodiversity further (no dead trees for woodpeckers, insects, decomposers)

age biodiversity in trees are important for the habitat of other organisms

• not many niches

pollutants and trees cycle

pollutants are emitted

smog create volatile org. compounds

deciduous vegetation absorbs volatile org. compounds through stomata (thru photosynthesis and CR)

urban areas effects

reduce ability to filter air

general forest benefits

filtering of air pollutants, removal of CO2 from atm, important habitat for organisms

filtering of air pollutants

stomata (leaf pores) pull in CO2 to perform photosynthesis. removes VOCs, NO2, and PM from air store in tree

removal of CO2 from storage/atm

trees take in CO2, store carbon as sugar, wood and other tissues release O2

deforestation consequences

reduces air filtering and carbon strong services

releases CO2 from decomp of leftover org matter

slash and burn

slash and burn

cutting and burning land for ag. releases co2, n2o, and water vapor into the ATM (all GHGs)

logging conflicts

timber production vs maintaining biodiversity. logging lobbies protect the ability to log/replant/cut them down

maintains biodiversity while timber production

ex. marble murrelet that nests in old growth coastal redwood forests. cutdown redwoods= bird habitat decrease

northern spotted owl

only lives in old growth coniferous forests = area that has not been harvested recently

courts stopped logging to protect owl habitats

impact of northern spotted owl court

over 150,000 logging jobs lost; timber industry mocked it as env. excess

jobs were already being lost due to decline in old growth and automation

scientists call it important indicator species machines already going to do jobs