The chart shows Environmental Protection Agency data for forestry practices in Minnesota in the 1980's. Clearcutting timber involves leveling all the trees in a forest in strips and allowing the forest to re-grow completely. Selective cutting involves felling
only larger timber trees and allowing smaller trees to remain until they are ready to be harvested. The EPA measured soil and
water loss in these areas, and also tested uncut sections of forests (controls). The EPA measured water loss (water yield) and
erosion (sediment loss).
According to the chart
A)
selective cutting causes more soil loss by erosion, than clear-cutting.
in 1982, more water was lost from clear-cut forest soil, than in any other
year.
B)
clear-cutting and selective cutting cause similar amounts of water (water
yield) to be lost from forested areas.
in 1984 and 1985, selection cutting actually conserved more water and
saved more soil from erosion, than the uncut control forest.
D)