4 I2 



Yearbook^ of Agriculture 1949 



surviving trees revealed that the mor- 

 tality of pines from western pine beetle 

 attack is closely related to growth 

 vigor the more vigorous the tree the 

 less likelihood of its becoming a victim 

 of the beetle. 



Further studies showed that suscep- 

 tible and resistant trees could be recog- 

 nized by visible characters connected 

 with the form and condition of the 

 crown and that pine stands could be 

 classified according to these characters. 

 By using this tree classification as an 

 index to relative resistance and suscep- 

 tibility, it is now possible to log selec- 

 tively the more susceptible trees and 

 reduce greatly the hazard of western 

 pine beetle infestations. 



IN WOOD PRODUCTS, the prevention 

 of insect damage is much simpler than 

 preventing damage in the forest itself. 



Some types of damage (like defects 

 in the standing trees) are in a sense un- 

 preventable, but by far the greatest 

 amount of injury to this class of mate- 

 rial comes after the tree is felled to 

 the green logs, to seasoned logs, to sea- 

 soned lumber, or to the product in use, 

 whether it be cross tie, pole, sill, floor- 

 ing, rafter, or implement handle. To a 

 great extent this type of damage can be 

 prevented. Its occurrence is a sign of 

 carelessness usually insufficient pre- 

 caution. Thus, if the log is attacked in 

 the woods by borers, the simplest rem- 

 edy is to get the log sawed more quick- 

 ly ; if injury occurs to the green lumber, 

 more rapid seasoning is necessary. 

 Damage that occurs to the product 

 after it is in use (such as termite dam- 

 age to cross ties and telephone poles or 

 Lyctus damage to flooring or imple- 

 ment handles) can frequently be pre- 

 vented by attention to construction 

 details, proper storage, or by treatment 

 with preservatives and insecticides. 



MANY SUGGESTIONS have been made 

 in the past three or four decades for the 

 prevention of forest-insect outbreaks 

 through forest management in many 

 types of stands. They have all been 

 made with the realization that they are 



more or less experimental and need the 

 test of practical application. They are 

 based on the known facts concerning 

 life histories and food preferences of 

 the insects, considered in connection 

 with the silvicultural characteristics of 

 the tree. 



Forest-management steps so as to 

 control species or age classes in the 

 interest of insect protection require a 

 distribution of cutting over forest prop- 

 erties which heretofore has rarely been 

 possible. An adequate system of tim- 

 ber-hauling roads is essential to apply 

 such cutting measures in the places 

 where they are necessary. In addition 

 to affording an opportunity to place 

 timber stands in a more resistant con- 

 dition to insect epidemics, adequate 

 road systems make it possible to salvage 

 recently killed and highly susceptible 

 trees before deterioration, which ren- 

 ders them worthless, occurs. Control of 

 such epidemics as do occur in the in- 

 cipient stage is also facilitated by ade- 

 quate transportation facilities. The 

 importance of road development for 

 application of stand management to 

 reduce hazards from insect epidemics, 

 to check the spread of epidemics, and 

 to salvage killed or infested trees is 

 now being recognized by both public 

 and private forest-land managers. 

 Progress in solving insect-control prob- 

 lems through management practices 

 will depend to a large degree on the 

 extension of permanent access-road 

 systems into national forest lands and 

 other ownerships where forest manage- 

 ment is being applied. 



Looking back some 40 years in the 

 practice of forest entomology from 

 the beginnings by Asa Fitch and A. S. 

 Packard, through the intensive biolog- 

 ical inquiry of Dr. Hopkins, which 

 formed the backbone of effective bark 

 beetle control as well as the basis for 

 suggestions for silvicultural methods 

 of preventing damage, to the coming 

 of modern insecticides and airplanes 

 one cannot help but wonder what is 

 ahead. 



Will it be the prevention of wide- 

 spread destruction of our resources by 



