INSECT DEPREDATIONS IN NOSTH 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 the 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, 

 protection of game, and as contributing to the real and aesthetic value 

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

 total damage 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 problem of insect damage to standing timber and 

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

 sources, it is evident that the reduction in value below that of healthj' 

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

 from handling defective material, has amounted to an equivalent 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 timber, given above. Since the 

 killed and damaged standing timber is involved in any given annual 

 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 prematurely de- 

 stroyed by insects, is equivalent to at least 3 per cent of the original 

 or mill value. 



HOW LOSSES CAN BE PRE^'ENTED. 



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 products can be controlled and serious damage prevented 

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

 agement and business methods. 



It is evident that if the information now available through publica- 

 tions of the Department of Agriculture and through direct cor- 

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

 result in the prevention of an equivalent of at least 30 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 : 



