FOREST TREES. 91

soil of North America; White clover springs spon- taneously wherever the land is cleared of the woods.

It seems an extraordinary fact in natural history, f_, that, wherever the original forest is destroyed in America, and the land left uncultivated, trees of a 1" different species should spring up. This is always observed where lands have been laid waste by fire. The first year, tall weeds, and raspberry and bramble bushes, shoot up; then cherry—trees, white birch, silver firs, and white poplars, appear; but seldom any tree of the genus previously growing on the space ; laid open by the devouring element. ’1‘

The great trees of the fir, maple, black birch, and beech tribes, when once destroyed, do not seem ever to be succeeded in the ground they occupied by trees

of the same kind.

* Sir Alexander Mackenzie observes, that on the banks of the Slave Lake, land, formerly covered wholly with spruce, fir, and birch, having been laid waste by fire, produced subsequently no- thing but poplars.