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72 Cards in this Set
- Front
- Back
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what is deforestation?
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the permanent conversion of forest land to an alternate land use (different than harvesting)
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deforestation is a --- problem with environmental consequences.
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social
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how many acres of forest are lost annually at a global level?
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35 million acres (state of wisconsin)
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what are some direct causes of deforestation?
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agriculture, logging, mining, pasture, charcoal, urban development
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what are some indirect causes of deforestation?
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population growth, land speculation, landless migrants, war and strife, political corruption
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what are estate crops?
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exported foods, monoculture, capitally expensive
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what does subsistence farming do?
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causes rapid degration of land that was raw forest; leaves poor soil, causes migration
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50-90 percent of latin america and asia depend on what form of wood?
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fuel
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when considering consequences of deforestation: what is loss of biodiversity?
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extinction due to habitat loss, loss of genetic potential, and loss of economically valuable products
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when considering consequences of deforestation: what is bushmeat?
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shrinks habitat, it's a cash crop rurally, unregulated
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when considering consequences of deforestation: what is poaching?
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tropical pets, high income with little risks, food trade, pelts
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what is a major effect of subsistence farming?
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erosion
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what is desertification?
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follow erosion and deforestation and overuse
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where is loss of fertility due to deforestation most common?
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tropics
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what 'environmental services' do forests provide?
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carbon sinks and water filters
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what is land tenure?
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system that governs ownership, access of land, and use of land (private ownership rare)
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what is agroforestry?
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where woody plants, crops, and livestock are grown simultaneously or sequentially
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what is agrosilviculture?
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crops and trees together; water competition is a problem
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what is agropasture?
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trees and pastures mixed together, crops mixed together. Limited by the climate and skill of farmer
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There is a -- fold difference in plantation productivity depending on climates globally (weak to strong).
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two
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how do plantations help with deforestation?
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1. only wood is removed
2. quick forest regeneration 3. well adapted trees |
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what allows for natural forest regrowth?
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thinning
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in some ways, plantations are -- crops for natural forests.
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nurse
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what year was the great yellowstone fire?
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1988
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what are the three main reasons for large wildfires?
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1. fuel load increases
2. dry conditions 3. ignition source |
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what are serotinous cones?
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cones opened by fire
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besides damage to property, what is a danger in fire?
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erosion
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what is the barrens cycle?
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pines replace themselves, harvested and then burns are frequent and low intensity
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what is backfire?
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a small fire set ahead of a large fire designed to use up the fuel source
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what is an invasive exotic?
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an organism that is able to enter, proliferate, and displace indigenous species or alter biological communities
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what is an example of a native invasive?
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black locust
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what are the three options of control on invasives?
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chemical, mechanical, biological.
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what is the 'main hope' for invasive control?
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biological control
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what is forestry?
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the management of forests to meet the objective of landowners and society
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What are the three phases of forest inventory analysis?
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1. GIS (big picture)
2. Ground (random plots) 3. Intense (entire ecosystem) |
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what is basal area?
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the sum of cross sectional areas of all trees in a given area
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what is gap analysis?
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regional habitat assessment that identifies species not adequately protected
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what is periodic increment?
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volume/age
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what is mean increment (annual)?
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volume per year/age
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periodic increment of a stand declines are -- years.
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30
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what is the net yield of a stand?
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gross mortality
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what is the gross yield of a stand?
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all forms in a stand
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what is roughly the economic max for harvest (years)?
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70
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what is silviculture?
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the science and art of applied ecological 'tools' and 'action' of forestry. REGENERATION of stands.
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what does the structure of silviculture mimic?
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succession
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what is clear cut?
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removal of all wood; result in even aged stands
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what is seed tree?
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few trees are left for seeds; removed following regeneration; even aged stands result
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what is shelterwood?
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trees removed over the course of 8-12 years; protection against insects and whatnot. even aged stands
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what is selective system?
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retaining 60-95% of trees; favors shade tolerant species
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what effect does high-grading selective logging do?
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reduces stand quality
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what effect does single-tree selection have?
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increased stand quality
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what percent of the planet is freshwater?
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3
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what fraction of freshwater is trapped in icecaps?
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2/3
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what percent of the world's freshwater are the great lakes?
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20
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what is water yield?
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amount of water leaving a watershed over time
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more trees = more/less water produced
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less
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what happened in the hubbard brook experimental forest?
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harvest caused stream flow to increase, evapotranspiration to decrease, and nitrates to increase
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water production is inversely proportional to the density of ---.
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vegetation
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what happened at the quablin reservoir?
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plantations of conifers used up much of the water.
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--- occurs during snowmelt to increase water.
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harvest
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what is the 'sponge' theory?
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forests have an infinite ability to water
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what is a big cause of erosion/flooding?
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roads on slopes
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what are three limitations of carrying capacity?
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habitat, predator-prey cycles, social
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what are a few disadvantages of fragmentation?
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opportunity for invasive species, parasitism
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what fixes fragmentation?
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secondary growth
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what are snags?
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course wood and dibris
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it takes 200 years to replace old growth forests. what is a substitute method for this?
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snagging
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what creates spacial heterogenerity?
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management at a range of scales of small to large clearcuts
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how do you get temporal diversity?
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controlling pioneer species
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what are two things that break up large areas of forest?
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railroads and private ownership
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what natural things make great corridors?
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rivers and streams
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which is the better retention system: aggregated or dispersed?
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aggregated because it retains snags
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