FORESTRY AND CONSERVATION 359 



needed, one or more groups may be started at the same time. It is, 

 however, desirable, for the sake of renewing the crop systematically, 

 to arrange the groups in a regular order over the lot. 



How to Cultivate the Wood Crop. Where only firewood is 

 desired, i. e., wood without special form, size, or quality, no atten- 

 tion to the crop is necessary, except to insure that it covers the 

 ground completely. Nevertheless, even in such a crop, which is 

 usually managed as coppice, some of the operations described in 

 this chapter may prove advantageous. Where, however, not only 

 quantity but useful quality of the crop is also to be secured, the 

 development of the wood crop may be advantageously influenced 

 by controlling the supply of light available to the individual trees. 



It may be proper to repeat here briefly what has been ex- 

 plained in previous pages regarding the influence of light on tree 

 devlopment. 



Effect of Light on Wood Production. Dense shade preserves 

 soil moisture, the most essential element for wood production; a 

 close stand of suitable kinds of trees secures this shading and pre- 

 vents the surface evaporation of soil moisture, making it available 

 for wood production. But a close stand also cuts off side light and 

 confines the lateral growing space, and hence prevents the develop- 

 ment of side branches and forces the growth energy of the soil to 

 expend itself in height growth; the crown is carried up, and long, 

 cylindrical shafts, clear of branches, are developed; a close stand 

 thus secures desirable form and quality. Yet, since the quality of 

 wood production or accretion (other things being e<jual) is in direct 

 proportion to the amount of foliage and the available light, and 

 since an open position promotes the development of a larger crown 

 and of more foliage, an open stand tends to secure a larger amount of 

 wood accretion on each tree. On the other hand, a tree grown in 

 the open, besides producing more branches, deposits a larger pro- 

 portion of wood at the base, so that the shape of the bole becomes 

 more conical, a form which in sawing proves unprofitable; whereas 

 a tree grown in the dense forest both lengthens its shaft at the ex- 

 pense of branch growth and makes a more even deposit of wood 

 over the whole trunk, thus attaining a more cylindrical form. 

 While, then, the total amount of wood production per acre may be 

 as large in a close stand of trees as in an open one (within limits) , 

 the distribution of this amount among a larger or smaller number 

 of individual trees produces different results in the quality of the 

 crop. And since the size of a tree or log is important in determin- 

 ing its usefulness and value, the sooner the individual trees reach 

 useful size, without suffering in other points of quality, the more 

 profitable the whole crop. 



Number of Trees Per Acre. The care of the forester, then, 

 should be to maintain the smallest number of individuals on the 

 ground which will secure the greatest amount of wood growth in 

 the most desirable form of which the soil and climate are capable, 

 without deteriorating the soil conditions. He tries to secure the 

 most advantageous individual development of single trees without 



