Vegetation of Northern Cope Breton. 411 



ascendancy over the others. Very often a leader which rises six 

 or eight feet above the main body of the tree w^ill have had all 

 its foliage blasted away by the wind-driven snow except for a 

 small, pyramidal crown at the very tip.^^ The general aspect of 

 these trees is suggested by the accompanying sketch (Fig. 57). 



Usually quite different in its behavior from the balsam fir is 

 the black spruce. In the balsam, while the lateral branches may 

 be capable of assuming the functions of the leader, it would 

 appear that they are able to do so only when very young, and 

 more often than not the leader seems to originate adventitiously 

 from either the main axis of the tree or a lateral branch. In 

 the spruce, on the other hand, the potential capacity for radial 

 growth in the normally dorsiventral lateral branches is much 

 more pronounced, and this capacity is less restricted to the 

 younger branches. Upon the death of the primary leader, a 

 number, often nearly all, of the lateral branches tend to assume 

 the radial habit, thus producing a clump of leaders, all of 

 approximately equivalent rank. As a result, while one leader 

 may sometimes become more prominent than the rest, the spruce 

 commonly acquires a bushy habit quite different from that of the 

 balsam. This dissimilarity of habit in the two trees is often 

 strikingly exhibited in the Krummholz association-type : the 

 balsam here is constantly tending to send a vigorous leader up 

 above the general level of the surrounding vegetation and 

 invariably possesses a short, sturdy trunk (Fig. 58) ; while the 

 spruce adapts itself readily to the prostrate Krummholz habit 

 and is virtually devoid of a distinct trunk. 



The tamarack behaves differently from either the balsam or 

 the spruce, being apparently better able than these species to 

 withstand the rigorous winter climate. The trees exhibit a 

 gnarled, scraggly aspect, but seldom are killed back to any 

 extent. 



Sometimes a forest of the sort under consideration is well nigh 

 impenetrable, and the undergrowth is essentially that .of the 

 coniferous climax forest of the region. But more often the trees 

 occur singly or in groups, with open spaces between in which 

 the vegetation is made up largely of the species characteristic of 



" A diflferent explanation for a similar phenomenon in the spruce has 

 been offered by Ganong ('04, pp. 188, 189). 



