32 THE GROWTH OF THE TREES. 



rather noble. It is to quietly see their stronger rivals flourish 

 until death overtakes them, and then to step calmly in and fill 

 for them their places. 



The existence of a young bud, however, is a precarious one. 

 It has many difficulties with which to contend. Often the 

 want of nourishment or light stunts its development ; insects 

 devour it, or a belated frost nips it in its early youth. The race 

 is truly one of the survival of the fittest. And how great is the 

 wisdom of this plan is readily seen, for should every leaf-bud 

 be allowed to grow, there would be as many branches the next 

 year as there were leaves the one preceding ; and this would 

 of course overburden the tree. Much of the perfect symmetry 

 with which leaves are arranged is therefore lost in the branches. 

 Within the tree, also, there is an instinct of self-preservation 

 which prompts it to produce buds on the wood wherever it has 

 been injured. They are the adventitious buds, and eventually 

 develop into the little lawless twigs which we so commonly 

 see on many trees ; the poplars and willows especially. 



When a tree makes what is called a definite annual growth, 

 the young shoots of the season burst boldly forth from the 

 buds, in which, it must be remembered, their parts are already 

 formed, and within a few weeks, or perhaps days, attain their 

 whole growth for that year. They then bestir themselves to 

 form and ripen their buds for the next season's similar and 

 rapid growth. Other forms of trees make an indefinite annual 

 growth. Throughout the summer their stems grow without 

 ceasing, until touched perhaps by an early autumn frost. They 

 take no time to form and ripen a terminal bud, and their upper 

 axillary ones are produced so late in the season that they can- 

 not properly mature. The growth of the next year, therefore, 

 is mostly dependent on lower axillary buds which are better 

 equipped. No main stem could possibly be continued in this way, 

 and soon the trunk is broken up into branches, which in the 

 same way divide and sub-divide into innumerable other branches 

 and branchlets. The trunk of the American elm serves as a 



