128 



AMERICAN FORESTRY 



and waste lands of the farms are either 

 the driest or the wettest ones. 



On the dry situations, the best prac- 

 tice requires the keeping of a good forest 

 cover, sufficiently dense to prevent dry- 

 ing out of the soil by sun and wind. 



On the very wet situations, fre- 

 quently much can be done to improve 

 moisture conditions by a small amormt 

 of ditching which can now be done 

 economically by the use of dynamite. 

 Often, land which is called too wet and 

 cold and now left to grow to worthless 

 scrub, with proper drainage can be 

 turned into the most fertile part of the 

 farm. Again, there are opportunities 

 on such land for special crops, such as 

 basket willow. If left in ordiary wood- 

 land much can be done by laying 

 special emphasis on selection of species 

 best adapted to the particular site, per- 

 haps supplemented by rome simple 

 ditching. 



For each locality the relationship of 

 trees to drought and soil moisture 

 should be noted, and only those species 

 used which are adaptible to the condi- 

 tions of soil and air moisture prevailing 

 over the area. 



Heat is one of the chief factors in the 

 distribution of trees. Thus, the forests 

 of the north are of different species and 

 types from those of the south. It is 

 necessary to know the requirements of 

 trees with respect to heat in order to 

 determine whether they can be used or 

 not. It is especially important to know 

 the susceptibility of any given species 

 to late and early frosts. Thus, the 

 catalpa, widely heralded as a most 

 valuable tree, is not adaptable over 

 most of New York, being too frost- 

 sensitive. Again, certain species, al- 

 though they will be able to live under 

 the lower temperatures and shorter 

 seasons of Northern New York, or in 

 the mountains, grow so slowly as to be 

 undesirable, while in waiTaer districts 

 their growth is rapid enough to make 

 them valuable. 



Beyond this choice of suitable species, 

 we have little control over the factor of 

 heat. The indirect effect of heat, such 

 as the drying out of the soil, can be 

 obviated, but this really is directly an 

 effect of moisture conditions. 



Minor influences of heat, such as 

 sensitiveness to frost-cracks, can to a 

 certain extent be controlled by regulat- 

 ing the density of the stand, etc.; in 

 forest practice, trees which are espec- 

 ially susceptible to such injury should 

 not be tmduly exposed but maintained 

 in more closed groups. 



Light also is one of the major factors 

 of growth. From a forestry stand- 

 point, it is, with moisture, the most im- 

 portant, because these two are the ones 

 most susceptible to control by forestry 

 methods, and show the greatest differ- 

 ence in returns following proper methods 

 in contrast to improper methods. 



Light is absolutely essential to tree 

 growth, as it is this that causes the 

 inorganic plant foods taken from the 

 soil and air to be assimilated by the 

 leaves into higher forms, available for 

 tree growth. Thus, one of the most 

 noticeable facts in growth is the relation 

 of any tree to the condition of light in 

 which it can, and does grow. 



Thus, a tree in the open may have its 

 branches low and spreading; while the 

 same species, grown in a dense forest, 

 will have a long, straight clean trunk, 

 with living branches only on the upper 

 portions. This is true, becuase in the 

 open, the total necessary leaf surface 

 can be most easily obtained by spread- 

 ing the branches laterally, while in the 

 forest it becomes necessary to keep the 

 crown well up with the rest, in order to 

 get light for the leaves. At the same 

 ime, the lower branches, deprived of 

 light, die and eventually fall off, leaving 

 the clean trunk of a forest tree. 



In relation to the development and 

 position of the crown or head, of a tree, 

 that part from the lowest large living 

 limb to the top, with respect to the 

 stand in which it is found, a tree is 

 divided into one of four classes: 



(L) Dominant, with full crown and 

 sufficient growing room to the sides, as well 

 as free light from above. When spreading, 

 and shading much more land than it 

 should, the tree is termed a "wolf tree." 



(2.) Co-dominant : Trees just a little 

 below the dominant trees in height, 

 with free light from above but crowded 

 from the sides; not entirely free, nor 

 with full crowns. 



