96 THM SYLVICULTUKAL SYSTEMS. 



4. TJie She1ter-n-no(l Sch'ction System. 



a. On'f/i)i mill Charartor. 



The forest is created, under the shelter of the old crop, l>v 

 the removal of single trees or small groups selected here and 

 there over the ^Yhole area, and this process goes on through- 

 out the whole length of the rotation, so that practically no 

 part of the whole forest is ever at rest. All age classes, from 

 one year old to the oldest, are constantly represented, by 

 single trees or small groups, over the whole area, and, theo- 

 retically, the work of selecting trees for cutting extends at all 

 times over the whole extent of the forest. In practice, how- 

 ever, the forest is divided into a number of blocks, which are 

 gone over in turn, so that cutting returns to the same part 

 only after the lapse of several years. 



//. Kxternal iJanyen^. 

 Views differ somewhat regarding the extent to which selec- 

 tion forests are exposed to external dangers, as compared with 

 the two previously mentioned slielter-wood systems. In the 

 absence of exact comparative observations it may be stated, 

 that in respect of drought the selection system acts very 

 favourably, because only very small plots are, at one time, 

 exposed to sun and air currents. The same may be said 

 in the majority of cases, as regards frost. Nothing definite 

 can be said in respect of damage by insects. As regards 

 damage by wind, snow, etc., views differ. 



'■. Prodwlioii of Wdod. 

 Here again actual comparative observations are not avail- 

 able. It has by no means been proved that less wood per 

 acre and per annum is produced under this than under either 

 of the two previous systems. Young growth, no doubt, 

 develops slowly, as it is much interfered with by the adjoin- 

 ing older trees, but this may be compensated for by a more 

 active development, when the trees have secured the full 



