INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 93 



the standing living, dying, and dead timber reduced in quality and 

 value by them in the forests of the country, to be found at any given 

 time, has been not far from 10 per cent of the total stand of mer- 

 chantable-sized timber (pp. 70-71). 



Considering tlic forest in its broadest sense as a source of national 

 wealth of a given value for all purposes, including direct utilization, 

 protection of land from erosion, protection of headwater streams, 

 j)r()tection of game, and as eontributing to the real and u'sthetic value 

 of health and pleasure resorts, it is evident to the writer that the 

 total danuige caused by insects has been equivalent to an average addi- 

 tional 5 per cent of the value of the merchantable-sized timber of the 

 entire country (p. 71 ). 



Considering the probU'ui of insect damage to standing timl)er aiul, 

 crude products on the basis of direct utilization of the forest re- 

 sources, it is evident that the reduction in \alue beh)\v that of healthy 

 timber or sound products at the time of utilization, including losses 

 from handling defective nuiterial, has amounted to an e<]uivalent of 

 at least 10 per cent of the average annual mill value of the aggre- 

 gate output of forest products of all kinds. This, of course, includes 

 the killed and damaged merchantable-sized timber considered under 

 the estimate relating to standing timl)er, given above. Since the 

 killed and damaged standing timber is involved in any given anmud 

 output, this estimate on a basis of utilization represents more nearly 

 a direct reduction in cash values (p. 71). 



The writer estimates that the annual loss caused by insects injuri- 

 ous to finished and utilized products, including the consequent in- 

 creased drain on the forest resources to replace that [)rematurely de- 

 stroyed by insects, is e(juivalent to at least 'A per cent of the oi'iginal 

 oi" mill \!ilue. 



now i/»ssi;s can uk i'Kk\kntki). 



The results of extensive investigations and of practical applications 

 during recent years have demonstrated that some of the most de- 

 structive insect enemies of American forests and of manufactured 

 and utilized jiroducts can be controlled and serious damage prevented 

 with little or no ultinuite cost over that involved in good forest man- 

 agement and business methods. 



It is evident that if the information now availai)le through publica- 

 tions of the Department of Agricidture and through direct cor- 

 respondence with its experts is properly utilized in the future it will 

 result in the prevention of an e(|uivaleut of at least 'M) per cent of 

 the estimated annual waste of forest resources that has been caused 

 by insects within recent years and thus contribute greatly to the 

 conservation of the forest resources. This can be accomplished as 

 follows : 



