CLIMAX COMMUNITIES : PRESENT DISTRIBUTION 



251 



now mostly decimated by fire and lumbering. Where pine was 

 dominant, Finns strobus tended to occur on sites with more favor- 

 able moisture conditions than the sand plains and ridges occupied 

 by P. resinosa. By some 268 these pure stands of pine are considered 

 to be climax, but many more ecologists agree that the pines are 

 successional species occupying inferior sites for long periods as 



FlG. 123. The oak-chestnut forest that once occupied the lower slopes of 

 much of the Appalachian system.— U. S. Forest Service. 



subclimax. That white pine especially carries over into the hard- 

 wood climax 180 is undoubtedly true. Its long life and relatively low 

 numbers suggest that these trees in the climax should be regarded 

 as relicts even though they can maintain their numbers by repro- 

 duction under openings appearing in the hardwood canopy. 161 



Postclimax forests of the northern conifers— tamarack, black 

 spruce, white cedar (Thuja occidentalis)— occupy the many bogs 

 throughout the area. The extensive areas denuded by lumbering 

 and fire are today largely occupied by second-growth forests of 

 aspen or pine. 



Oak-Chestnut Association.— As the mixed mesophytic forest 

 becomes restricted to special habitats to the east and southeast of 

 its center, the slopes and uplands are occupied by what was, until 



