Fungi living off plant roots also help their hosts absorb nutrients and resist root pathogens. Re-establishing a healthy rainforest requires re-establishment of the whole ecosystem.

"...the forest thrives despite its soil, rather than because of it."

Soil exposed by deforestation is subject to extensive erosion:

A forest on undulating terrain loses 1 T/ha/year, 20-160 T/ha/yr for a coffee plantation, 60-100 T/ha/yr for pastureland, and 1,000 T or more with field crops.

Seeds

Seeds of tropical plant survive only a short period of time in dormant state. Often they are vulnerable to temperatures outside a very narrow range (e.g., 73-80 F). Temperate-zone plants endure summer, winter. freezing, thawing.

Not carried by wind, depend on creatures to transport pollen and seeds

Plants produce lar~e fleshy fruits to attract carriers



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The Tropical Rain Forest: A Nonrenewable Resource. A. Gomez-Pompa, C. Vazquez-Yanes, S. Guevara.


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Tropical Deforestation and Habitat Fragmentation in the Amazon: Satellite
Data from 1978 to 1988. David Skole and Compton Tucker



Global estimates of tropical deforestation:

69,000 km2/yr in 1980
100,000 to 165,000 km2/yr in late 1980's


(state of Iowa covers about 130,000 km2)