FOREST PROTECTION 31 



Means of Protection 



I. PROTECTION AGAINST INSECTS INFESTING THE CAMBIAL 

 BARK OF THE TRUNK. 



A. AGAINST SCOLYTID^E (BARK BEETLES). 



(1) Conduct the logging operations at that season of the year at which 

 the logs are apt to become infested; and after infection, remove the bark, 

 entirely or partially; or move the logs rapidly to water or mill. In other 

 cases, conduct logging at that season at which the debris left are not apt 

 to form incubators for Scolytidae; or else long before swarming (e. g., cut 

 pine at Biltmore in early winter, to avoid Dendroctonus frontalis). Com- 

 pare Agric. Year Book, 1902, p. 275 for D. frontalis and p. 281 for D. pon- 

 derosce. 



(2) Girdle, peel, lodge, fall or blaze trap trees of inviting diameter, 

 shape and position prior to the time of the swarming of the Scolytida3. Com- 

 pare Agric. Year Book, 1902, p. 269. Trap trees might be prepared in the 

 district to be logged next. Try to destroy the trapped ScolytidaB without 

 injury to the Cleridae and their allies. 



(3) Remove or burn logging debris; or swamp the tree tops left, thus 

 creating unfavorable conditions of moisture. Sometimes it is possible to 

 use the debris as traps. Compare, however, Entom. Bui. No. 21, p. 23, for 

 advice to leave the debris, so as to divert predatory Scolytidse from sound 

 trees to debris. 



(4) Leave all trees (also trap trees) in the woods which prove to be 

 incubators for Ichneumonidse, Bracoriidse, Chalcididae. Remove the outer 

 bark so as to assist ovipositing Ichneumons in reaching their prey. Intro- 

 duce arid breed parasites. (Bui. West Va. Agr. Station, p. 326.) 



(5) Counteract reckless deadening by farmers engaged in clearing their 

 fields. 



(6) Adopt proper diameter limit in logging where a Scolytid attacks 

 only trees of certain diameter classes. Remember, e. g., that the spruce 

 having under 10" d.b.h. is safe from D. piceaperda. 



(7) Begin logging in districts recently damaged by fire, storm, sleet. 



(8) Remove even worthless trees, if they are apt to act as incubators. 

 Keep in mind, on the other hand, that trees with dead cambium are not 

 attacked by cambium boring Scolytida?. 



(9) Have at hand, ready for use, permanent means of transportation 

 so as to be able to operate when and where you ought to operate; particu- 

 larly, when and where timber begins to die. 



(10) Conduct thinnings in a manner and at a time counteracting in- 

 fection by Scolyticlse. Remove dying and injured (by lightning) trees, 

 also trees weakened in vigor. 



