39 terms

APES Chapter 12


Terms in this set (...)

Jamaica Bay Wildlife Refuge
Major place for birds to stop at on their migration route; the salt marshes and brackish waters of the bay were damaged by a large flow of freshwater from treated sewage,
messing with salt content affects the filter feeders which are important to the food chain
Public service function
Nature benefitting people and the environment indirectly
The professional growing of trees
Timber investment management organizations--viewed forestland as an opportunity to profit by buying and selling timber; they owned 60% of the 80% of Maine's industrial forest land.
Mainly taiga boreal forest--number 1 in lumber production
Rain shadow
One side of the mountain is lush and has lots of rainfall, where the other side does not
Nations that have two-thirds of the world's forests
Russia, Brazil, Canada, The United States, China, Australia, Democratic Republic of Congo, Indonesia, Angola, Peru
Breakdown of forests in the US
56% is privately owned
33% is federal land
9% is state land
3% is county and town land
Percentage of wood produced in the world that is used for firewood
Vegetation of any kind can affect the atmosphere in four ways:
1. By changing the color of the surface and thus the amount of sunlight reflected and absorbed
2. By increasing the amount of water transpired and evaporated from the atmosphere
3. By changing the rate at which greenhouse gases are released from Earth's surface into the atmosphere
4. By changing "surface roughness" which affects wind speed at the surface
Ecology of Forests
Each species has it's own niche and is adapted to specific environmental conditions.
-water content in the soil
-tolerance of shade
A group of trees usually of the same species or group of species and often at the same successional stage. (small to medium size)
Even-aged stands
All live trees began growth from seeds and roots germinating the same year. Same height but different girth and vigor
Uneven-aged stands
Have at least three distinct classes
Virgin Forest
(Old-growth forest)-A forest that has never been cut
Second-growth forest
A forest that has been cut and regrown
Rotation time
the time between cuts of a stand
place where people grow trees
Dominant trees
Tallest, most common, most vigorous
Codominant Trees
Fairly common, sharing the canopy or top part of the forest
Intermediate Trees
Forming a layer of growth below dominants
Suppressed Trees
Growing in the understory
Site quality
The maximum timber crop the site can produce in a given time
Cutting of all the trees in a stand at the same time
Benefits and Disadvantages of Clear-cutting
Benefits: good with flat land, and more cost effective, good with early succession species
Disadvantages: Bad on slopes because of soil erosion
Selective cutting
Individual trees are marked and cut; used if you only need a certain kind of tree
Benefits and Disadvantages of Selective cutting
Benefits: trees are left behind to help the ecosystem
Disadvantages: More expensive, harder to find specific trees
Smaller, poorly formed trees are selectively removes
Benefits: allows healthy trees to grow better, reduces fire risk
Narrow rows of forest are cut, leaving wooded corridors whose trees provide seeds
Benefits and Disadvantages of Strip-Cutting
Benefits: Protection from erosion
Disadvantages: Edge effect-effects on the ecosystem go further into the forest than just the strip taken out
Shelterwood cutting
Practice of cutting dead and less desirable trees first, and later cutting mature trees
Seed-tree cutting
Removes all but a few seed trees(mature trees with good genetic characteristics and high seed production) to promote regeneration of the forest
Benefits and Disadvantages of Seed-tree cutting
Benefit: more space for new seeds, regenerating the forest with the native trees, leaving some degree of habitat for animals
Disadvantages: Too many trees are being cut down
Slash and burn-after everything is harvested, everything else is burned
Two kinds of ecological sustainability
1. Sustainability of the harvest of a specific resource that grows within an ecosystem
2. Sustainability of the entire ecosystem
Increases erosion, increases the frequency of landslides, amount of runoff, and sediment load in streams
History of Deforestation
Forests were cut in Greece and then continued northward in Europe; Fossil records suggest that prehistoric farmers in Denmark cleared forests so extensively that early-successional weeds occupied large areas; Problem is severe in the tropics because of rapid human population growth
Causes of Deforestation
1. Clear land for agriculture and settlement
2. Use or sell timber for lumber, paper products, or fuel
3. Logging by large timber and local cutting by villages
4. Indirect deforestation: the death of trees from pollution or disease--may continue with global warming
Certification of forestry
Organizations whose main function is to certify forest practices