INSECT DEPREDATIONS IN NORTH AMKIMCAN I'dlJKSTS. ()9 



-dead Ir.xik «»ii the Iniiiks would conll'ihiitc to the ^pi'ciuliiiir of cidwii 

 firi's and thus tin- hark on iho ciitiro iiifcsied tiimUs would be Milli- 

 rirntly scorched to kill (he insects. Therefoi-e. complete lii-e control 

 niav easily contriliute to nioic t'xtended dej)ivdations hy insects on tlio 

 livin<r tiinhei', thus incri'asinir. rather than diininishinir. the need for 

 insect conti'ol. However, the settin<!; of fires or peiMiiittinL'' them to 

 hiii'M for the pui'|)ose of coml)at iiiii: insects should ne\er l)e iniiler- 

 takon or permitted. 



I>iii'((biHti/ of his('<f-l,-ill(<l tliiihcr. — Some (d" the matui'cd i:ii-ch 

 trees which evidently died jis a result of lUd'oliat ion Wy the lai"ch 

 worm between iNNl and 1S!S.*), and whii-h had escaped sui)se(|uent 

 dei)redations by Hre and wood-l)orin<jf insects, were found i)V the 

 writer in lt*()S to be standiiiij: and sound enou<j:h to be utilized for 

 railroad ties and many other purposes. Under sinnlar conditions the 

 heartwood of red spruce and wlute jiiiie in the East, of Kn.irelmami 

 spruce in the Rocky Mountains, and of Douglas lii- in the Northwest 

 coast reirioii have been foinid by the writer to be sound enouirh for 

 profitable utilization for l)ulp wood, lumber, fuel, and other pur- 

 poses from twenty to thirty years after it had been killed by insects 

 or fire. Thus it is shown that timber killed by insects and fire would 

 be available for utilization for many years Avere it not for injuries 

 through the secondary attacks of wood-boring insects and the de- 

 struction of insect -killed timber by forest fires. 



IXTERKEI.ATION OF FOREST INSECTS AND FOREST FINCI. 



Derail foJlo^r'nuj liijiD'i/ hy insects. — It is well known that the 

 burrows in the bark and wood of li\ing and dead trees and in 

 the crude and finished products often contribute to the entrance of 

 bark and wood decaying fungi. Deterioration and decay are thus 

 far more rai)id than would otherwise be }iossible. It is al>o known 

 that trees injured and dying from i)rimarv attack by jjiirasitic fungi 

 are attractive to certain insects which brtH'd in the bark and wood 

 of sickly and dying trees, and that certain other complicated troubles 

 affecting forest trees are the result of an intimate interrelation and 

 interdependence of insects and fungi. There can be no doubt, how- 

 ever, that certain species and groups of both insects and fungi are 

 inde])endently capalde of attacking and killing perfectly vigorous 

 and healthy trees. 



SUMMARY AND KSlIMArKS I{KnATIN(; TO < 11 AK \< TF.R AND EXTENr (iF 



INSECT OAMACiE. 



Tiie killing of trees by insects; the (hnnage by titeni to the wood 

 of living, dying, an<l dead timber; the d«'struction of insect-kille<l 

 timber by sul)se(pient forest fires; the damage to fire-killed tiinl)er 

 by insects; and the damage from decay resulting fr«)m ins(»ct injuri(»s 

 to the wood, have all been more or less continuous for centuries and 

 are still going on in the forest and woodland areas of this country. 



