


1901 | GENETIC DEVELOPMENT OF FORESTS 395 
in due time a maple-beech-hemlock condition is the result. 
Thus, starting with an herbaceous vegetation similar to that on 
the fossil beach, there is a transition through the heath and 
coniferous forest to the climax society. Making due allowance 
for difference in climate, it is probable that all the glacial clay 

- I.—The lakeward slope of a sand dune on North Manitou island covered by 
a forest. Balsam is the most common tree. The undergrowth is very dense, and the 
deep shade furnishes favorable conditions for the development of maple and beech. 
The evergreen forest is encroaching on the evergreen heath seen at the foot of the 
slope, and the latter, in turn, is encroaching on the fossil beach society situated in the 
foreground. : 
lands in the region under discussion have passed through some- 
what similar stages, since they were formed by the action of the 
last ice sheet. As a rule, where the vegetation has not been dis- 
turbed by man, they are clothed with maple-beech-hemlock 
forests. Where clearings are made, as will be shown subse- 
quently, they rapidly attain the same forest condition if let 
alone 
