Deforestation.docx

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Department
Child and Family Studies
Course
ENSC 1005
Professor
Heather Kaye
Semester
Fall

Description
Monday November 19, 2012 Deforestation & Loss of Biodiversity Types of Forests & their Importance” 1) Old-growth forests - Virgin, regenerated forests - Mainly found in west coast temperate forests of B.C and boreal coniferous forests in another Ontario (Temagami) - Provide ecological niches, habitats & food for a variety of wildlife - Decay of vegetation returns nutrients to soil 2) Secondary-growth forests - Result of secondary succession after removal by human activities (clear- cutting for timber or conversion to cropland) or natural disasters (fire, hurricanes, volcanic eruption) Commercial Importance: – Lumber, fuel (50% worldwide), pulp, medicines, foods Ecological Importance: – Sponges (slow down run-off, absorb & hold water, reduce amount of sediment washing intro streams & lakes by reducing soil erosion) - Influence climate (reduce wind, moderate temperatures) - Involved in carbon cycle (absorb CO2), provide habitats - Provide food and oxygen, reduce noise pollution * Long-term benefits of a tree clearly exceed short-term economic benefit * Destruction of Old-Growth Forests: - 50% if Canada is forested (-75% as second-growth forests) - Canada has 10% of the world’s forests => largest exporter of timber products world-wide (>$30 billion/year) - We have lost 60% of our old-growth forests (most of them in B.C.) - 90% of logging in Canada involves clear-cutting - Each year clear-cutting of old-growth forests & temperate rainforests in B.C. removes twice as many tress as the harvest from all U.S. national forests combined - Clear-cutting in Clayoquot Sound brought the problem of deforestation in Canada to the attention of the world and in 1995 the B.C. government ended clear-cutting in Clayoquot Sound under serious pressure from environmental groups & unfavorable international publicity Types of Forest Management: 1) Even-aged management - Trees in a given stand are maintained at about the same age & size - Goal is to grow and harvest trees using monocultures * Quantity Growth* - One or two cuttings of all or most trees from the area, then the site is usually replanted with seedlings of one or more species of the same age - These forests are viewed as lumber & fibre factories 2) Uneven-aged management - Variety of tree species in a given stand are maintained at many ages & sizes * Quality Growth * - Goal is biological diversity, long-term producti
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