A SUMMARY OF THE TIMBER RESOURCE REVIEW 



65 



There are many different kinds of insects. Bark 

 beetles are responsible for 90 percent of insect- 

 caused mortality. In terms of growth impact, 

 bark beetles are somewhat less important, and 

 the defoliators and other insect groups become 

 more so. However, even with respect to growth 

 impact, bark beetles account for three-fifths of the 

 insect damage (.table 42 and fig. 30). The "other 

 insects" group includes hardwood borers, white 

 pine weevil, pine tip moth, cone and seed insects, 

 Saratoga spittlebug, and balsam woolly aphid. 



MORTALITY-1952 



STEM 



DISEASES 

 INSECTS 

 FIRE 

 OTHER 



OTHER 



BARK BEETLES 



WEATHER 



ANIMALS MISC. 



GROWTH IMPACT 



STEM (HEART ROT AND OTHER) 



OTHER 



OTHER 



WEATHER ANIMALS MISC. 



OTHER 



10 20 30 40 50 



PERCENT 



includes Coastal Alaska 



Figure 30 



Table 41. — Timber mortality on commercial forest 

 land, 1952 » 



GROWING STOCK 



Cause 



All sec- 

 tions 



North 



South 



West 



and 

 Coastal 

 Alaska 



Fire 



Million 



cu. ft. 



240 



770 



1,000 



840 



70 



590 



Million 



cu. ft. 



40 



460 



70 



210 



40 



330 



Million 



cu. ft. 



130 



70 



110 



120 



200 



Million 

 cu. ft. 

 ' 70 



Disease 



240 



Insects - 



820 



Weather 



510 



Animals 



30 



Other . 



60 







Total 



3, 510 

 -770 



1, 150 

 -150 



630 

 -240 



1, 730 



Salvage 



-380 



Net loss 



2,740 



1,000 



390 



1, 350 



LIVE SAWTIMBER 



Fire _ 



Million 

 bd.-ft. 

 780 

 2, 240 

 5,040 

 3,390 

 190 

 1, 030 



Million 



bd.-ft. 



70 



910 



100 



500 



80 



420 



Million 

 bd.-ft, 

 300 

 230 

 410 

 400 

 e) 

 430 



Million 

 bd.-ft. 

 410 



Disease 



1, 100 



Insects.- - 



4, 530 



Weather 



2, 490 



Animals 



110 



Other _ _ 



180 







Total 



Salvage 



12, 670 

 -3,090 



2,080 

 -280 



1, 770 

 -620 



8,820 

 -2, 190 



Net loss 



9, 580 



1, 800 



1, 150 



6, 630 



' See footnote 1, table 39. 

 2 Less than 5. 



Table 42. — Sawtimber mortality from insects and 

 disease in 1952 and growth impact oj 1952 

 damage 



INSECTS 



Cause 



Mortality ' 



Growth impact 



Bark beetles 



Defoliators 



Other insects _ 



Million 



bd.-ft. 



4,530 



30 



480 



Percent 

 90 

 1 

 9 



Million 

 bd.-ft. 

 5, 410 

 1,310 

 1, 900 



Percent 

 63 

 15 

 22 







All insects 



5,040 



100 



8,620 



100 



DISEASE 



Heart rot and other stem 



diseases 



Systemic diseases 



Root diseases 



Foliage diseases 



610 

 360 

 300 

 40 

 930 



27 

 16 

 13 

 2 

 42 



16, 180 



640 



600 



110 



2,360 



81 

 3 

 3 

 1 



Other diseases _ . 



12 







All diseases 



2, 240 



100 



19, 890 



100 



! 



1 See footnote 1, table 39 



^ 



