362 HORTICULTURE, FORESTRY, FLORICULTURE 



or "final harvest" crop. For this 300 to 500 trees per acre of the best 

 grown and most useful kinds may be selected, which should be dis- 

 tributed as uniformly as possible over the acre. These, then or as 

 many as may live till the final harvest are destined to grow into 

 timber and are to form the special favorites as much as possible. 

 They may at first be marked to insure recognition ; later on they will 

 be readily distinguished by their superior development. The rest, 

 which we will call the "subordinate" crop, is then to serve merely as 

 filler, nurse, and soil cover. 



What Trees to Remove. It is now necessary, by careful obser- 

 vation of the surroundings of each of the "final harvest" crop trees, 

 or "superiors," as we may call them, to determine what trees of the 

 "subordinate" crop trees, or "inferiors," must be removed. All nurse 

 trees that threaten to overtop the superiors must either be cut out or 

 cut back and topped, if that is practicable, so that the crown of the 

 superiors can develop freely. Those that are only narrowing in the 

 superiors from the side, without preventing their free top develop- 

 ment, need not be interfered with, especially while they are still use- 

 ful in preventing the formation and spreading of side branches on 

 the superiors. As soon as the latter have fully cleared their shafts, 

 these crowding inferiors must be removed. Care must be taken, how- 

 ever, not to remove too many at a time, thus opening the crown cover 

 too severely and thereby exposing the soil to the drying influence of 

 the sun. Gradually, as the crowns of inferiors standing farther away 

 begin to interfere with those of the superiors, the inferiors are re- 

 moved, and thus the full effect of the light is secured in the accretion 

 of the main harvest crop; at the same time the branch growth has 

 been prevented and the soil has been kept shaded. Meanwhile thin- 

 nings may also be made in the subordinate crop, in order to secure 

 also the most material from this part of the crop. This is done by 

 cutting out all trees that threaten to be killed by their neighbors. 

 In this way many a useful stick is saved and the dead material, only 

 good for firewood, lessened. It is evident that trees which in the 

 struggle for existence have fallen behind, so as to be overtopped by 

 their neighbors, can not, either by their presence or by their re- 

 moval, influence the remaining growth. They are removed only in 

 order to utilize their wood before it decays. 



It may be well to remark again that an undergrowth of woody 

 plants interferes in no way with the development of the main crop, 

 but, on the contrary, aids by its shade in preserving favorable 

 moisture conditions. Its existence, however, shows in most cases 

 that the crown cover is not as dense as it should be, and hence that 

 thinning is not required. Grass and weed growth, on the other hand, 

 is emphatically disadvantageous and shows that the crown cover is 

 dangerously open. 



The answer to the three questions, When to begin the thin- 

 nings, How severely to thin, and How often to repeat the operation, 

 must always depend upon the varying appearance of the growth and 

 the necessities in each case. The first necessity for interference may 

 arise with light-needing species as early as the twelfth or fifteenth 



