'ZS:l tendinct of cuowdki) woods aftkh kauly youth. 



an nnfavonvable soil, frost. (lron<:;ht. fire, hail, li'^litniuf,'. 

 injuries to the crown, stem or roots, attacks hy insects or 

 parasitic funf;i. Ajijain, the crowns and stems of trees may be 

 broken by stronj^ winds, snow and rime, or sin^^de trees and 

 whole groups may be tin-own down. From one or the other 

 of these causes there will always be found a certain (piantity 

 of material which, if not removed as speedily as possible, will 

 stimulate the increase of injurious in.sects and of fungi. The 

 latter have of late years been recognised as the cause of 

 considerable damage to woods, since modern botanists have 

 explained many important phenomena formerly- imjoerfectly 

 understood as to their origin. In this respect attention is 

 invited to the ravages of 'rraiitcfcs radicipcrda and Afiaricus 

 meUens in Scotch pine and spruce woods ; of Trametea Pini, 

 PcriderniiKDt Pini in Scotch pine woods (so-called foxy trees) ; 

 Peziza (Dasi/.^ci/jiJia) M'iUhoiiiDiii, tlio larch canker fungus; 

 ,¥jcidin)u clatiiiinn, the silver fir canker fungus, the various 

 species of PolyponiH on broad-leaved and coniferous trees, etc. 

 Far greater, howevei', than the danger from fungi, is that 

 from insects. Many species of the latter are apt to become 

 disastrous to whole woods, extending over large areas. Most 

 of these find suitable conditions for multiplying in the presence 

 of dead and dying trees, refuse wood, stumps, etc. Hence it 

 is advisable that all such material should be removed as 

 speedily as possible. 



Where regular thinnings, presently to be prescribed, are 

 carried out, all dead and dying trees are removed at the same 

 time. Such thinnings occur only at certain intervals, and as 

 it would l)e detrimental in many cases to leave the dead 

 material in the forest until the next thinning comes 

 round, it is frequently necessary to make special cuttings 

 for the purpose of removing it; these are called " di\if irnod 

 ciittiniis"' or '' clrtoii)!;! ciiltinns." In carrying these out all 

 valuable material should be used or sold, and the refuse, 

 if possible, burned under supervision. If danger from 

 insects l)e inmiinent, it may be necessary to remove the 



