64 



TIMBER RESOURCES FOR AMERICA'S FUTURE 



Table 39. — Mortality and growth impact resulting 

 from 1952 damage, by cause 



Table 40. — Mortality and growth impact resulting 

 from 1952 damage, by section 



GROWING STOCK 



Cause 



Mortality ' 



Growth impact 



Fire 



Disease 



Million 



cu. ft. 



240 



770 



1,000 



840 



70 



590 



Per- 

 cent 

 7 

 22 

 28 

 24 

 2 

 17 



Million 

 cu. ft. 

 1,690 

 5,050 

 1,780 



950 

 1,010 



730 



Per- 

 cent 

 15 



45 



Insects 



Weather. 



16 



8 



Animals 



Other 



9 



7 



Total 



Salvage 



3,510 

 -770 



100 



11, 210 

 -770 



100 



Net loss 



2,740 





10, 440 









LIVE 



SAWTIMBER 







Fire 



Disease 



Insects 



Million 

 bd.-ft. 



780 

 2,240 

 5,040 

 3,390 



190 

 1,030 



Per- 

 cent 

 6 

 18 

 40 

 27 

 1 

 8 



Million 

 bd.-ft. 

 7,370 



19, 890 

 8, 620 

 3,870 

 2,720 

 1,360 



Per- 

 cent 

 17 

 45 

 20 



Weather 



9 



Animals 



Other 



6 

 3 



Total 



Salvage 



12, 670 

 -3,090 



100 



43, 830 

 -3,090 



100 



Net loss _ 



9,580 





40, 740 









' Estimates represent actual mortality in 1952. They 

 differ slightly from estimates presented in table 29 which 

 represent the current level of mortality as indicated by 

 trends over a long period of years, as determined in 1952. 



Fire ranked lower than either insects or disease 

 as a destructive agent in terms of either mortality 

 or the more inclusive concept of growth impact. 

 In 1952, fire caused about one-fourth as much 

 mortality as did weather. Probably the major 

 reason why damage estimates show other causes 

 to be more serious than fire is because of the 

 tremendous strides made in forest fire prevention 

 and control, and the much more effective action 

 against ftre than against other destructive agents. 

 Fire remains an extremelj' important menace to 

 forest productivity even under present-day inten- 

 sity of prevention and control effort. If these 

 efforts were relaxed, fire could easily become the 

 number one destroyer of the forest. 



Damage ascribed to weather, animals, and a 

 miscellaneous group of other factors is significant 

 and should not be overlooked. Weather damage 

 from wind, ice and snow, lightning, and drought 

 caused greater mortality than disease or fire in 

 1952, but had far less growth impact. In that 

 year, damage from weather was greater in the 



GROWING STOCK 



Section 



Mortality • 



Growth impact 



North 



South 



West and Coastal 



Alaska 



Million 

 cu. ft. 

 1, 150 

 630 



1,730 



Per- 

 cent 

 33 

 18 



49 



Million 

 cu. ft. 

 4,310 

 4,000 



2,900 



Per- 

 cent 

 38 

 36 



26 



Total 



Salvage 



3,510 

 -770 



100 



11, 210 

 -770 



100 



Net loss 



2,740 





10, 440 









LIVE SAWTIMBER 





Million 



Per- 



Million 



Per- 





bd.-ft. 



cent 



bd.-ft. 



cent 



North 



2,080 



16 



13, 840 



32 



South 



1,770 



14 



15, 440 



35 



West and Coastal 











Alaska 



8,820 



70 



14, 550 



33 



Total 



12, 670 



100 



43, 830 



100 



Salvage 



-3,090 





-3,090 





Net loss 



9,580 





40, 740 









■ Estimates represent actual mortality in 1952 in con- 

 trast to estimates appearing in table 29 which represent 

 the current level of mortality as indicated bj' trends over 

 a long period of years, as determined in 1952. The esti- 

 mates are the same in either case, except for the West. 



West than in other sections. Damage from a 

 variety of animals, including domestic livestock, 

 big game, porcupines, squirrels, and mice, is more 

 serious in the North and West than in the South. 

 Such damage can be controlled or reduced although 

 measures may prove costl}-. 



Insects Cause the Greatest Mortality 



Insects w^ere responsible for 40 percent of all 

 the mortality of sawtimber in 1952, and 28 percent 

 of the mortality of growing stock. In terms of 

 sawtimber, insects outrank disease as a cause of 

 mortality by a ratio of 2 to 1 , and fire by a ratio of 

 7 to 1. In terms oi the more comprehensive 

 effects of growth impact, however, insects were 

 onlj' about half as damaging as disease, and about 

 on a par with fire as a destructive agent. 



On a sectional basis, insects were far more im- 

 portant in the West than in other sections, and of 

 least importance in the North (table 41). Ninety 

 percent of all sawtimber mortality caused by 

 insects was in the West, and about half of all sa\v- 

 timber mortality in the West from all causes was 

 due to insects. 



