deforestation and loss of biodiversity. three general types of forests tropical temperate polar
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Deforestation and Loss of Biodiversity
Three General Types of ForestsTropicalTemperatePolar
Old Growth ForestsVirgin (uncut) forests and forests that have not been disturbedExamples: forests of Douglas firs, giant sequoia, and coastal redwoodsUses: habitat for wildlife species, and standing dead trees(snags) and fallen logs decay and add nutrients to the soil
Second Growth ForestsStands of trees resulting from secondary successionExamples: most of the forests in the U.S. and approximately 40% of tropical forests
Economic Importance of Forests
Provide lumber for housingBiomass for fuelwoodPulp for paperMedicines and moreWorth more than $300 billion a year
Ecological Importance of Forests
Slows runoff Reduce amount of sediment in streamsInfluence climateVital to global carbon cycleProvide wildlife habitat
Threats to Forest Ecosystems
Unsustainable loggingClear cuttingSelective cuttingStrip cutting
FireSurface firesCrown firesThe Age of Mega-Fires
Threats to Forest Ecosystems con’t
Insects and diseaseNonnative species introduced accidently and deliberatelyCausing billions of dollars in damage and loss
Climate ChangeLoss of species as temperatures riseFor example: alpine tundra in VA
Tropical ForestsLocation: equatorial Latin America, Africa, and AsiaTypes: rainforests, tropical deciduous forests, dry and very dry deciduous forests
Importance of Tropical Forests
Supplies 50% of the world’s annual harvest of hardwood50%-90% of terrestrial species found thereProvides hundreds of food products(coffee, tea, cocoa, spices, nuts, chocolate & fruits)Natural latex rubber, resins, dye, & essential oils
Importance of Tropical Forests Continued
Contain the active ingredients for ¼ of the world’s prescription drugsStrains of rice, wheat, and corn developed from wild tropical plants
Impact of DeforestationLoss of biodiversity (plants and animals)ErosionLoss of climate control
Causes of Tropical Deforestation
Population growth and povertyPolicies of governmental and international lending agencies
Degradation of a Tropical Forest
Degradation of a tropical forest always begins with a road, usually one cut by a logging company.
Other Reasons for Degradation
LoggingPeasant farmingCattle ranchingCash cropsMiningDamsTree plantations
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