Hill: Penobscot Vegetation 331 



Populus grandidentata 8 



Picea canadensis 8 



It will be evident from this table that the species which 

 occur in 50% or more of these areas of woodland, chosen as 

 typical of the Penobscot Bay region, are the character trees 

 of the Canadian-Transition forest as a whole. The require- 

 ments of these character trees and of their associated spe-. 

 cies will be summed up as follows : 



Beiula alba var. papyrifera. As the figures indicate the 

 paper birch is widespread throughout the area, and it oc- 

 curs in nearly all stands save the very oldest. The tree is 

 short lived, as compared with other hardwoods, for it is sus- 

 ceptible to decay and also to wind damage, since the roots 

 do not anchor it at all firmly in the ground. It is intoler- 

 ant of shade and so reproduces poorly when associated with 

 hardwoods. In burned and lumbered localities, however, re- 

 production is very dense, and since most of the second and 

 third growth woods are of this sort, the birch is the com- 

 monest tree to be found in the region. 



Fag-us grandifolia. The beech is a conspicuous species 

 on well drained land where the soil is deep, especially in 

 loamy soil. It is very tolerant and reproduces prolifically,. 

 trees of all ages being present in the stand. On cut over 

 land and burned areas it exhibits good reproduction by 

 sprout growth and may often be the only species present in 

 such locations. 



Picea rubra. The red spruce is able to grow on any sort 

 of soil and in all situations, and it is very tolerant. It re- 

 produces well on lumbered areas and in localities where there 

 is little hardwood competition. A bare, moist, mineral soil 

 or duff is the most favorable for reproduction, while the 

 leaf litter of a hardwood forest prevents it. Once started, 

 in a locality, however, the spruce is able to exist for years 

 with almost no sunlight, and although usually outdistanced 

 by hardwoods it persists and forms a characteristic second 



