57 



The headings "Range" and "Distribution in Pennsylvania" are 

 often of special importance on account of their identificational value. 

 Many species of trees have a limit to their geographical distribution 

 in this State, and by knowing this accurately one is often able to 

 identify a species by the process of elimination. The Sweet Buckeye 

 and Fetid Buckeye are found only in a few counties in the western 

 part of the State. The Red Pine and Paper Birch are found only 

 in the northern part, while the White Cedar is found only in a few 

 counties in the extreme southeastern part of the State. If one finds 

 a birch tree growing in the forest in the southern part of the State, 

 he can feel certain that it is not Paper Birch, because this is beyond 

 the southern limit of this species. A coniferous tree growing wild 

 on the top of the South Mountains in Franklin county, Pennsylvania, 

 must be a Pine, Hemlock, or Red Cedar, because no other coniferous 

 trees grow there. Further we know that it cannot be the Red Pine, 

 because this species does not extend so far south in the State, and 

 on the basis of habitat we can also be reasonably sure that it is not 

 the Yellow Pine, the Jersey or Scrub Pine, nor the Hemlock, because 

 they very seldom ascend to the tops of the mountains, but usually re- 

 main at lower elevations. Likewise, if a maple tree is found at the 

 same place we know that it is the Red Maple or Mountain Maple 

 because they are the only Maples found in that particular locality. 

 If Magnolia trees are found in Centre county one can be certain tha t 

 the species is not Laurel Magnolia, (Magnolia virginiana), because 

 this species has its western limit of geographical distribution at 

 Caledonia, near Chambersburg, Franklin county. The habitat also 

 aids considerably in identifying various species. A birch tree found 

 growing upon a mountain slope or mountain top is rarely the River 

 Birch, because the latter usually frequents moist locations like 

 banks of streams and lakes. Chemical composition of the soil also 

 influences distribution. A soil rich in lime seldom has Chestnut 

 growing upon it, at least in stands, while other species seem to 

 thrive upon such soil. No doubt at least 99% of the Cumberland 

 Valley in this State was originally timbered with a heavy forest, but 

 very little of it was Chestnut, while on the adjoining mountain slopes 

 of both the South and North Mountains, Chestnut is the prevailing 

 species. Just as the Chestnut is essentially a tree of the slopes so 

 the White Oak is essentially one of the bottom lands, and Table 

 Mountain Pine of the mountain tops. 



The heading "Importance of the Species" was introduced simply 

 to give general information concerning the forestal significance of 

 the species and their adaptability for ornamental purposes. This 

 heading is especially important when we realize that of the more 

 than one hundred and twenty-five species of trees found in this State, 



