INSECT DEPREDATIONS IN NOHTIl AMKHICAN FoltESTS. 09 



(lend l):irk on tlif Iniiik- would cont rilnitt- to (he ^iJi-cadiiiir of ci-own 

 fires aiul thus (he l>:irk on the entire infested trunks wouM he sulli- 

 ciently seorehed to I<ill the insects. Therefore, complete lii'e control 

 may easily contril)utc to more extended depredations by insects on the 

 livinfr timber, thus increasing, rather than diminishin<jr. the need for 

 insect control. However, the settin<r of lires or j)ermittinir them to 

 burn for the purpose of combating: insects shoiUd i>e\ei' be under- 

 taken or permitted. 



DurahU'itii of Ihsict-l/ilh d tlnther. — Some of the matureil larch 

 trees Avhich evidently died as a result of defoliation by the larch 

 worm betwei'ii ISSl and bs.s."). and which had escaped subsefiuent 

 depredations by fire and wood-boring insects, were found by the 

 writer in 11)08 to be standing and sound enough to be utilized for 

 railroad ties and many other purposes. Under similar conditions the 

 heartwood of red spruce and white pine in the East, of Engelmann 

 spruce in the Rocky Mountains, and of Douglas fir in the Northwest 

 coast region have been foinid by the writer to be sound enough for 

 profitable utilization for pulp 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 woidd 

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

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

 struction of insect-killed timber by forest fires. 



INTKHHKLATIOX OF FOKEST INSECTS AND FOREST FUNGI. 



Dcfdii folloir'nir/ injiiri/ hy insects. — It is well known that the 

 burrows in the i)ark 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 tlms 

 fai' more ra|)id than would otherwise be possible. It is also known 

 that trees injured and dying from ])rimarv attack by jKU-asitic fungi 

 are attracti\"e to certain injects which brtH'd in the bark and wood 

 of sickly and dying trees, and that certain other complicated ti-oubles 

 afl'ecting fori st trees are the result of an intimate interndat ion and 

 interde|)en<lence of insects and fungi. There can l>e no doul)t. how- 

 evei'. that certain specie> and gi'ou|)s of l)oth insects and fungi are 

 inde|)endently capable of attacking and killing p<'rfectly vigorous 

 and healthy trees. 



Sl.MMAKV AND KSTIMATKS I{KI.ATIN<; TO CIIAUAC TF.K AND KX'IT.NT OF 



iNsi:« I da.mam:. 

 The killing of trees by insects; the damage l)y them to the wood 

 of living, dying, and dead timber: the destruction of insect-kille(l 

 timber by subsecjuent forest lires: the damage to lire-killed timber 

 by insects; and the damage from decay resulting from ins(>ct injuries 

 to the wood, havi> all been more or less contimious for centuries and 

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



