﻿WHITE PINE UNDER FOREST MANAGEMENT. 11 



best for all trees. Where the species differ is in their ability to 

 thrive under less favorable conditions. In" the North woods, for 

 example, maple, beech, and hemlock need better soil conditions 

 than white pine and do not thrive well enough on poorer soil 

 to compete with it. White pine also grows best in deep, fresh, 

 loamy soils, and the largest white pine trees were found scattered 

 among the hardwood forests on such sites. The heavy shade cast 

 by the broadleaf trees, together with their capacity, not shared by 

 the pine, to sprout abundantly when cut or burned down, made it 

 impossible for white pine to monopolize the best soils, and its forests 

 were found, therefore, in drier and less fertile situations. Sand is the 

 principal constituent of the soils on which grew the best white pine 

 forests. The deeper, moister, and more loamy the sand the better 

 are the trees developed. By its rapid growth on such soils the pine 

 is able to exclude slower-growing species like hemlock, beech, and 

 maple, and more light-needing • trees like red, pitch, and jack pine. 

 The last three species are less exacting than white pine, and will 

 form forests on soils too dry for the latter. On the other hand, 

 white pine is often found in poorly drained, somewhat swampy 

 situations, in company with fir, arborvitse, tamarack, and other 

 swamp-inhabiting species. In such places, however, its growth is 

 apt to be relatively slow. 



Compared with the size of its trunk and crown, the root system 

 of white pine is small. There is no taproot, but three or four stout 

 roots grow downward slantingly, and in time give the tree a firm 

 hold on the soil. On shallow soils with impervious hardpan or 

 underlying rock strata the roots spread out close to the surface; in 

 deeper soils they penetrate downward for 3 or 4 feet. Growth is 

 less vigorous on shallow than on deep soils, because the former more 

 quickly lose their moisture. 



Tree leaves give up daily to the air great quantities of water, which 

 the roots have absorbed from the soil. The more foliage a tree has 

 the larger and. more active must be its root system. Since the 

 amount of light received by a tree directly influences the amount of 

 its foliage, it must also influence the development of the roots. 

 Thus, pine trees which grow in the open and have heavy foliage also 

 possess deep and extensive root systems, while those .in dense stands 

 and with little foliage may have deep but rarely large or extensive 

 roots. 



LIGHT REQUIREMENT. 



Light is the agency by which plant leaves manufacture food for 

 the tree out of water drawn up through the roots and carbon dioxide 

 obtained from the air. The amount of light necessary to sustain 

 life, however, varies with different species. Compared with other 

 trees, white pine may be classed as intermediate in its light require- 



