Chapter 10 Outline - Chapter 10 Outline 1 Why Should We...

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1. Why Should We Care about Biodiversity? a. Intrinsic value- these components exist regardless of their use to us. a.i. Protecting biodiversity on this basis is basically an ethical decision. b. Instrumental value- their usefulness to us in the form of numerous economic and ecological services. b.i. Use value – benefits us in the form of economic goods and services, ecological services, recreation, scientific information, and preservation of options for such future uses. b.ii. Nonuse value: b.ii.1. Existence value: the satisfaction of knowing that a redwood forest, wilderness, orangutans, or wolf pack exists, even though if we will never see it or get direct use of it. b.ii.2. Aesthetic value: many people appreciate a tree, a forest, a wild species such as a parrot, or a vista because of its beauty. b.ii.3. Bequest value: based on the willingness of people to pay to protect some forms of natural capital for use by future generations. c. Biodiversity helps maintain the structure and function of ecosystems and control populations of pests and other species, provides a variety of medicines and drugs. 2. Types of Forests a. Three major types of forests: a.i. Old – growth forest: an uncut or regenerated forest that has not been seriously disturbed by human activities of natural disasters for at least several hundred years. a.ii. Second – growth forest: a stand of trees resulting from natural secondary ecological succession. a.iii. A tree plantation / tree farm: a managed tract with uniformly aged trees of one or two genetically uniform species that are harvested by clear-cutting as soon as they become commercially valuable. a.iv. 63% are secondary growth, 22% are old growth, and 5% are tree plantations. 3. Global Outlook: Extent of Deforestation a. The world’s forests are being cleared at a rate of .3%-.8% per year. b. Cutting down large areas of forests has important short-term economic benefits but it also has a number of harmful environmental effects. 4. Harvesting Trees a. The first step in forest management is to build roads for access and timber removal. b. Selective cutting – intermediate aged or mature trees in an uneven aged forest are cut singly or in small groups. b.i. Reduces crowding, removes diseased trees, encourages growth of younger trees, maintains a stand of trees of different species and ages, and allows a forest for multiple purposes. c. Strip cutting – variation that can allow a more sustainable timber yield without widespread destruction is strip cutting. c.i. Involves cutting a strip of trees along the contour of the land, with corridor narrow enough to allow natural regeneration within a few years. d. Clear cutting – a complete removal of trees 5. Types and Effects of Forest Fires a. Three types a.i. Surfaces fires: usually burn only undergrowth and leaf litter on the forest floor. a.i.1.
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This note was uploaded on 12/08/2011 for the course ENVIRONMEN 101 taught by Professor Chow during the Spring '11 term at Marquette.

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Chapter 10 Outline - Chapter 10 Outline 1 Why Should We...

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