FACTORS INFLUENCING REPRODUCTION 8^5 



Reproduction. — The reproduction has been touched upon under com- 

 position. The most conspicuous tree in the young growth up to about 

 3 feet high is perhaps balsam fir ; it is everywhere, even though there 

 are no fir seed trees within apparent reach. Closer examination shows, 

 however, that the fir is relatively infrequent in the younger reproduc- 

 tion, less than five years old. Furthermore, the high mortality of the 

 fir after reaching the sapling stage makes -it seem probable that fir will 

 be inconspicuous in the main stand of the next generation. Next in 

 abundance in the reproduction is white pine. It is thrifty and promis- 

 ing and comes in heavily in some years and not at all in others. Except 

 where white pine is nearly pure, spruce and cedar play a conspicuous 

 part in the reproduction, the spruce alone often equalling the young 

 white pine even where the main stand is predominantly pine. There 

 is, it seems, a struggle between pine and spruce, the latter holding the 

 advantage because of its ability to survive under the shade of the for- 

 mer, but the pine nevertheless holding its own and perhaps even en- 

 croaching on the domain of the spruce. 



Cedar Association 



Composition. — The composition of the cedar association, like that of 

 the two foregoing associations, is variable; white cedar {Thuja occi- 

 dentalis) predominates, but never forms pure stands, as does the 

 spruce and white pine. Over much of the island the cedar association 

 merges with the spruce and also, though to less extent, with the pine. 

 Considerable areas of it contain scattering large white-pine trees. The 

 chief associates are fir, spruce, and white pine among the conifers and 

 red maple, white birch, and aspen among the deciduous trees. The 

 proportions of spruce vary considerably and often change gradually 

 from place to place, causing the cedar to merge imperceptibly into the 

 spruce association. White pine is often abundant, but the line of de- 

 markation between the white pine and cedar associations is always 

 more distinct than that between the cedar and the spruce. The white 

 pine appears to be a relic of the days when the stand was more open, as 

 after fire or some other accident, and not a permanent component of 

 the stand. 



Occurrence. — The cedar association occurs only on moist sites and 

 is the characteristic forest of the wet, swampy flats. On the sites and 

 in every little moist hollow cedar tends to crowd out all other com- 

 petitors. It also comes in, sometimes even predominating, on rocky 

 ledges, probably where there is abundant moisture from higher up the 

 slope. 



