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Unformatted text preview: Forest Ecosystems and Deforestation
Forests have a high density of trees and host a high diversity of wildlife. Primeval forests covered most
of Europe and North America ten thousand years ago, but now only small pockets of primary (old-growth)
forests exist. Globally forests cover 30% of land area, compared to pre-human coverage of ~50%. The
importance of forests led the United Nations to declare 2011 the International Year of Forests.
Forests provide a host of ecosystem services. They host roughly 80% of the earth’s species, and produce
abundant organic matter that accumulates to form thick, rich soils, especially in temperate regions. They play
an essential role in the global cycling of nutrients such as carbon and nitrogen (Raven, Berg et al. 1995).
Forests act as both sources and sinks. For example, forest trees are a sink for atmospheric carbon dioxide,
which they fix through the process of photosynthesis:
6 CO2 + 6 H2O = C6H12O6 + 6O2
This chemical reaction shows that trees are also a source for atmospheric oxygen. In fact, trees are the
primary source of the oxygen...
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This note was uploaded on 01/08/2014 for the course SUST 510 taught by Professor Marker during the Fall '14 term at Black Hills State University.
- Fall '14