HERMAN H. CHAPMAN 21 



start, either in age, or location, enables some trees to take 

 the lead. This once obtained gives the tree a start over 

 its slower and smaller rivals which it never loses until with 

 increasing size and spread of crown it comes into competi- 

 tion with trees of its own class, when the struggle begins 

 again; and again the larger and thriftier tree is bound to 

 win. Those overtopped in growth, first endeavor at all 

 costs to maintain their height growth, but lose most of their 

 side branches and become much reduced in size of crown 

 with a total height only slightly less than the stronger trees. 

 Later on, they lose more and more ground and the crowns 

 of the neighboring trees begin to close above them. Soon 

 afterwards these trees die from loss of light. Thus we find 

 the trees in an even-aged stand classified by their crowns, 

 which are a sure indication of the thrift and prospects of 

 the tree. Those trees which overtop their neighbors in 

 height and have a well-developed crown, are known as dom- 

 inant trees. The crowded trees which still maintain their 

 struggle for light by keeping up their height growth, are 

 the intermediate class. The overtopped trees which are 

 about to die are in the suppressed class. It almost never 

 happens that an intermediate or suppressed tree becomes 

 dominant in such a stand. This could occur only by the 

 destruction of the dominant trees which are crowding it. 

 Since the numbers constantly fall off, it is always the in- 

 termediate and suppressed trees that disappear. Trees are 

 continually dropping out of the dominant class into the 

 classes below, as they fail to keep up their initial advan- 

 tage. 



The Old Age of a Stand. — From the period when height 

 growth ceases, the history of the stand is quite different. 

 Trees continue to drop out, but most of those remaining 

 are able to hold their own and may be regarded as victors 

 in the struggle for existence. The trees as they grow older 

 need more light, and the branches in the lower crowns die 

 faster. The crown becomes thinner and when a tree dies 



