28o George E. Nichols, 



structure of these regional climax forests is considered in brief 

 detail in the following paragraphs. Their general aspect is 

 illustrated by Figs. 10-12. 



The trees of the climax forest. — The nature of the individual 

 associations which comprise the climax association-complex of 

 the lowland varies considerably. In some places the forest is 

 made up wholly of deciduous trees, but more commonly it con- 

 sists of a mixture of deciduous and evergreen species. The 

 various trees which may enter into the composition of the forest 

 are named below, together with remarks as to their frequency 

 and ecological importance. ( i ) Deciduous Species : — Beech 

 (Fagns grandifolia) is almost invariably the predominant species, 

 in some cases including fully 65 per cent, of the mature trees. 

 Sugar Maple (Acer saccharum) is always present and usually 

 ranks second in abundance to the beech. Yellow Birch (Betula 

 liitea) is likewise omnipresent and sometimes outnumbers the 

 sugar maple. Red Maple {Acer ruhriim) is rarely absent, and 

 frequently occupies a prominent position in the forest. Paper 

 Birch (Betula alba papyrifera) ordinarily grows scattered 

 through the forest. In some stands these five species are the 

 only large-sized trees represented in the mature growth. The 

 northern Red Oak (Qnerciis rubra ambigua) is widely distributed, 

 and in some localities, as at Pleasant Bay and in the vicinity 

 of Cape North, is an important constituent; but in most places 

 it is only sparingly represented, and often it is absent. White 

 Ash (Fraxinus americana) is not uncommon in many low inter- 

 vale forests, but elsewhere it is comparatively rare. Balsam 

 Poplar (Populus balsamifera) is occasionally encountered in 

 virgin forests. (2) Evergreen Species (conifers) : — Balsam fir 

 {Abies balsamca), in the majority of cases, is a conspicuous, 

 though not necessarily abundant, member of the forest, growing 

 intermixed with the various deciduous species. Hemlock {Tsuga 

 canadensis) is locally abundant and sometimes is the pre- 

 dominant tree ; but often it is absent or represented only by 

 scattered trees. White Pine {Finns Strobus) is also an important 

 constituent, locally, at any rate. It is particularly characteristic 

 of the steep, well-drained, rocky slopes and ridges which flank 

 many of the larger streams ; but repeated cutting has thinned 

 out this tree to a greater extent than any other single species. 

 White Spruce {Picea canadensis) grows sprinkled here and there 



