8 IMPROVEMENT THINNINGS IN 



sandy soil or on a hill top should not be thinned as heavily as one 

 on low, moist ground; because under such circumstances the soil 

 must be kept shaded to retain the scanty supply of moisture. The 

 age of the trees and the kind of timber desired have an influence 

 on the decision of what to take. For instance, if the owner of a 

 chestnut sprout stand wishes it to yield poles rather than ties or 

 lumber, he should thin it lightly. 



The simplest problem of thinning is in a woodlot consisting of 

 but one species. We first divide the trees into four classes: dom- 

 inant, intermediate, suppressed, and dead. Dominant trees have 

 large, full crowns, well up in the light. Intermediate trees receive 

 light from above, but are somewhat crowded at the sides, some 

 more than others. Suppressed trees are those which have been 

 wholly overtopped by their more vigorous neighbors, and are 

 slowly dying. A moderate thinning would consist in the removal 

 of the intermediate trees which are closely pressed by their neigh- 

 bors, and all the suppressed trees if they will make a marketable 

 product. Dead trees do no injury to the growing crop, and are 

 only removed to improve the appearance of the woods, or as a pre- 

 caution against fires. 



When the woodlot contains a number of species the problem be- 

 comes more complicated, for we have the relative value of species 

 as another factor which we must consider. The relative worth 

 of different species depends in part on their value in the market; 

 in part on the owner's plans as to the final disposition of the wood- 

 lot; and in part on their adaptability to the soil in which they are 

 growing. 



The hard woods of the eastern part of the United States are 

 divided into two types: the northern and the southern. Generally 

 speaking, the order of preference in the northern hard woods would 

 be rock maple, paper birch, yellow birch and beech. Among the 

 southern hard woods the names might be arranged as follows : 

 chestnut, white ash, red oak, hickory, white oak and soft maple. 

 Gray birch, poplar and wild cherry are usually classed as forest 

 weeds, and are taken out. Where these latter three species are 

 growing by themselves, and are not interfering with other and 

 better trees, they can of course be left; but they are not worth any 

 improvement work. 



Where white pine is mixed with deciduous trees, it is usually 

 favored at their expense ; and spruce in the higher altitudes should 

 be similarly benefited. Pitch pine, however, is in a class below 



