HERMAN H. CHAPMAN 17 



resemble the orchard form of the growth, since the struggle 

 is taking place underground, and the trees influence each 

 other only through their roots. In extremely dry regions 

 such scattered trees will have all the attributes of open- 

 grown shade trees, including the buttressed and swelling 

 roots, but since the supply of moisture is so small, the 

 crowns will be correspondingly scant and open rather than 

 full and dense. Such forests are common through the drier 

 portions of the West. 



When the rainfall is sufficient and the soil retentive, as 

 is largely the case through the eastern half of America, the 

 struggle is transferred to the crowns, and becomes one for 

 the possession of light. As many trees will grow on an acre 

 as can secure light enough to live. In a forest stocked with 

 the full number, the crowns touch and throw almost com- 

 plete shade. The growth of the trees in height is stimu- 

 lated, and their sidebranches are killed by the shade of 

 their competitors. Those which grow fastest in height sur- 

 vive. The form of such trees is strikingly different from 

 the same species grown in open places. The first live 

 branches are much farther up the bole, and in old trees, 

 most of the lower branches have not only died and fallen 

 off, but the scar has closed over completely, giving the 

 trunk the appearance of having never possessed those lower 

 branches. What crown there is, is confined to the top, where 

 it gets the light from above, or, if one side or the other hap- 

 pens to be exposed to the light, we find the crown abnormal- 

 ly developed on this side. The bole is slender and holds 

 its size well, approaching a cylinder in form and not taper- 

 ing rapidly until the live crown is reached. The base does 

 not show a large swelling, although some is always present. 

 Such a tree, protected by its neighbors from the force of 

 the wind and from excessive evaporation of soil moisture, 

 has not developed the extremely resistant form of the open 

 grown tree. If the stand is cut away, leaving it alone and 

 exposed, several things may happen. If the species is 



