


1901 | GENETIC DEVELOPMENT OF FORESTS 321 
found poplars mixed with the birch. In this neighborhood 
stumps of pines indicate the former forest. In places repeated 
fires have reduced the area to heath conditions. This is shown 
by a number of heath plants like Preris aguilina, Gaultheria procum- 
bens, Cladonia rangiferina, etc. The presence of few seed-produc- 



1G. 16.—A second-growth forest of pines and poplars on a fossil beach near 
Marquette. The pines are slowly gaining ascendancy over the short-lived poplars 
and these will in time disappear. 
ing pines in the neighborhood will probably account for the’ 
absence of many pine seedlings. 
Thus, no matter how far toward the first stage in the life-his- 
tory a forest is reduced, if not interfered with by human agencies, 
ultimately the climax forest society is reached, but not without 
first having passed through a pine or a poplar-birch stage. A 
maple forest was never observed to follow a maple forest except 

