Deforestation and Loss of Biodiversity

Three General Types of Forests Tropical Temperate Polar

Old Growth Forests Virgin (uncut) forests and forests that have not been disturbed Examples: forests of Douglas firs, giant sequoia, and coastal redwoods Uses: habitat for wildlife species, and standing dead trees(snags) and fallen logs decay and add nutrients to the soil

Second Growth Forests Stands of trees resulting from secondary succession Examples: most of the forests in the U.S. and approximately 40% of tropical forests

Economic Importance of Forests Provide lumber for housing Biomass for fuelwood Pulp for paper Medicines and more Worth more than $300 billion a year

Ecological Importance of Forests Slows runoff Reduce amount of sediment in streams Influence climate Vital to global carbon cycle Provide wildlife habitat

Threats to Forest Ecosystems Unsustainable logging Clear cutting Selective cutting Strip cutting Fire Surface fires Crown fires The Age of Mega-Fires

Threats to Forest Ecosystems con’t Insects and disease Nonnative species introduced accidently and deliberately Causing billions of dollars in damage and loss Climate Change Loss of species as temperatures rise For example: alpine tundra in VA

Tropical Forests Location: equatorial Latin America, Africa, and Asia Types: rainforests, tropical deciduous forests, dry and very dry deciduous forests

Importance of Tropical Forests Supplies 50% of the world’s annual harvest of hardwood 50%-90% of terrestrial species found there Provides 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 drugs Strains of rice, wheat, and corn developed from wild tropical plants

Impact of Deforestation Loss of biodiversity (plants and animals) Erosion Loss of climate control

Causes of Tropical Deforestation Population growth and poverty Policies 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 Logging Peasant farming Cattle ranching Cash crops Mining Dams Tree plantations