24 North American Forests and Forestry 



never amounts to anything more than giving special 

 direction to the processes initiated by nature. 



One of the principal weapons which trees have in 

 the propagation of their species is the production 

 of immense quantities of seed, which are spread 

 broadcast, trusting to accident that some will find 

 a favorable spot to sprout and grow into a new tree. 

 Evidently, the more seeds are sown, the greater is 

 the probability that some of them will find such a 

 spot. Therefore trees that are very fertile have an 

 advantage over trees which produce a less quantity. 

 But no matter whether few or many seeds are pro- 

 duced, a very small percentage ever succeed in be- 

 coming trees. In fact, it happens not rarely that of 

 all the seeds scattered over the ground in any given 

 year not a single one ever reaches the state of a 

 seedling tree. Those who have never observed 

 these relations are apt to assume that in a given 

 tract of woodland, growing healthily under undis- 

 turbed natural conditions, one will be able to find 

 trees of all ages, from the patriarch of several cen- 

 turies down to the little seedling just showing the 

 tip of its stem above the litter on the forest floor. 

 But such conditions are rather rare, and the reason 

 for that is not very hard to find. In the first place, 

 the trees do not bear seed every year. Varying 

 according to species and perhaps to habitat and 

 other conditions, what is known as a seed year oc- 

 curs but once in three, four, or five years, as the 

 case may be. In such a year, every tree of the 

 species, old enough to bear fruit at all, is full of 



