INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 67 



Construction timbers and oth(M* woodwork in new and old l)iiild- 

 infTs are often so sei-iously dainai^cd hy i)o\vder-|)ost beetles, whit*' 

 ants, and otiiei- wood-horini!: iiix'cts thai the aU'ectcd inatei'ial has 

 to be removed and rej)laced by new, or the entiic sliiicture torn down 

 and rebuilt. ( noi)kius. VMVut.) 



Construction tind)ers in l)rid<;es and like structures, railroad ties, 

 telephone and teleirraph i>()les, mine props, fence posts, otc., are 

 sometimes seriously injured by wood-boriu*; larva>, termites, black 

 ants, carpenter bees, and powder-post beetles, and sometimes reduced 

 in efficiency from 10 to 100 ])er cent. 



INSKCTS IN rilKIK UKI.ATION TO IIIK HKDl ( TION oK I III KK SII'IM.IKS OF 



IIMUKH. 



Insects not only reduce future suiijilies by killino: the mature 

 trees and destroviuijf the wood of timber that is inaccessil)le for 

 utilization, but throuiih injuries inflicted upon trees durin*? the 

 floweriuir, fruiting, germinating:, seedling, and sapling periods of 

 early growth they jirevent normal rejiroduction and devel()i)ment. 

 (Hopkins, 1!)04^/. 100()c.) 



IXTKHHKL ATIONS OF TOREST INSECTS AND FOREST FIRES. 



Investigations conducted by the writer and assistants in all sec- 

 tions of the country during the past ten j'ears indicate to them 

 quite conclusively that the average jiercentage of loss of merchant,- 

 able timber in the forests of the entire country to be charged to 

 in.sects during a five or ten year period is infinitely greater than 

 most people realize. (Hopkins, IDOfir/, pp. 4-5, 1008/^ p. 345, 1900?>, 

 pp. 5, 24: Forbes, 1000, pp. 51-52.) 



Losses from forest inserts. — The writer estimates (p. 70) that for 

 a ten-year period the average amount of timber in the forests of the 

 entire country killed and reduced in value by insects woidd represent 

 an average loss of $()2,500.000 annually." 



It has been estimated (Hopkins, 1005/>, p. 5: lOOS^/. p. 102) that 

 the Black Ilills beetle killed ai)proximately 1.000,000.000 feet b. m. 

 of timlx'r during a period of ten years, which at $2.50 per thousand 

 would amount to an average of $250,000 annually. This is merely 

 one example of very destructive depredations by a single species of 

 barkbeetle in a single natioiiid forest. ** (See also \i. 70.) 



Prof. Lawrence Bruner, state entomologist of \ei)raska, at a meet- 

 ing of the American .Vssociation of Economic Kntomologists, held at 



" LosHcs from forest fires. — It has l)pen estimated that ** on the nverajie. since 

 1.S70, forest fires liavc yearly cost ,$."»0.oO().0()0 in tiinlu'r." (rirvt'laiid. T.. Jr., 

 11M)9. p. 8.) 



''It has hct'ii (>stiinat«Ml that lht> losses nf liailicr from forost llrcs on all of 

 the National Forosts of flic Fiiitrd States fmni I'.MC. to IJKJS. inclusivo. average 

 only $lGr..O02 aumially. ( Cli'velaiul. T., jr.. I'.Mis, p. r,n.) 



