.'330 Proceedings Portland Society Natural History 



Coptis trifolia Pyrola chlorantha 



Rubus pubescens Mitchella repens 



Bryophytes are almost entirely lacking and the absence 

 of a carpet of vegetation is noticeable at once, as is the open 

 character of the forest as a whole. 



The majority of the woods in the Penobscot Bay region, 

 however, differ more or less in their composition from the 

 examples cited above, which approach very closely the tran- 

 sitional climax forest as described for other localities. Of- 

 ten white pine and red oak are the most conspicuous mem- 

 bers of a stand, or the white cedar or red maple may be 

 prominent, while again pure stands of one species or an- 

 other may occur. It would be impossible within the limits 

 of the present discussion to take up all of the various types 

 of woods which exist and the factors which are responsible 

 for their occurrence. It will be sufficient to indicate what 

 species are present in the forests ; and the general require- 

 ments of these species. 



An examination of some fifty tracts of typical well-devel- 

 oped upland woods was made to determine what trees were 

 present. The white birch was found to occur in forty of 

 the fifty areas, or in 80% of the cases. The following table 

 shows the percentages for the other species. 



Fagus grandifolia 60 



Picea rubra 60 



Quercus rubra 60 



Tsuga canadensis 50 



Betula lutea 50 



Pinus Strobus 35 



Acer rubrum 35 



Abies balsamea (mature trees) 35 



Acer saccharum 25 



Thuja occidentalis 10 



Betula populifolia 10 



Fraxinus americana 10 



