HERMAN H. CHAPMAN 15 



situations ill-adapted to more valuable kinds. This pro- 

 fusion of species is in a sense a drawback, for German for- 

 esters with only two or three important trees to study, soon 

 perfected their systems of cultivation and built up an or- 

 derly scheme of management. We must adopt new plans 

 for every species and every region and the knowledge 

 gained in one locality will not necessarily apply elsewhere. 



V. SILVICS. 



The Forest versus the Single Tree. — A forest must 

 be studied from two standpoints — first, the individual 

 trees and their characteristics, and second, the attri- 

 butes of the forest as a whole. Trees growing singly 

 not only follow different laws of growth and devel- 

 opment than when crowded together in a forest, but the 

 effects of a forest upon the soil are not secured unless the 

 trees cover practically the entire surface. An illustration 

 of tree growth which does not properly constitute forest 

 growth is found in orchards or in shade trees. Each tree 

 is allowed full crown space and develops a symmetrical 

 form with a short trunk, branching near the ground. 

 No two species assume the same form, even when open 

 grown. White oaks will send horizontal branches to 

 great distances and grow into hemispherical shaped crown. 

 Hard maple takes an oblong or elliptical shape, while the 

 white elm always develops the umbrella shaped crown 

 which makes its presence so desirable as a shade tree over- 

 hanging roadways and lanes. 



Such large and well-developed crowns mean a corre- 

 spondingly large root system, which is secured by the ab- 

 sence of competition with other trees. The size of the crown 

 is an indication of the freedom of root growth. It often 

 happens that old trees in city streets die as a result of inter- 

 ference with the roots, through the laving of pavements 

 impervious to water. Trees which are found in a thriving 

 condition when growing entirely alone, have usually de- 



