Disease Losses - Timber and Forest Products 
Annual losses of standing timber due to forest diseases are 
estimated at about 150 million cubic feet, including nearly 700 
million board feet of sawtimber. Heavy damage occurs year in 
and year out from attacks by a myriad of diseases. Heart rots 
are of particular importance, since they attack most species of 
timber and result in heavy losses in the form of cull and lowered 
quality of the remaining wood. Root rots and virus infections 
reduce growth and make trees susceptible to attacks by insects 
or subject to wind throw. Bark canker fungi, wilts, rusts, and 
various other diseases similarly destroy timber, inhibit growth, 
and lower tree quality. 
Losses due to reduced growth and lowered quality because of 
disease are far greater than losses of standing timber. In the 
aggregate they total an estimated 1. billion cubic feet annually, 
including about 5.5 billion board feet of sawtimber. Altogether, 
losses due to forest diseases amount to possibly $56 million, of 
which $50 million represents cull increase and growth loss and 
#6 million loss of standing timber. 
Other heavy losses of forest products also result from various 
diseases. Decay in buildings and other structures caused by 
improper construction, lack of wood preservation, and other 
factors annually destroysan estimated 10 billion board feet of 
lumber, plywood, and other timber products. About 6 percent of 
the pulpwood stored in northern pulp and paper mills is lost 
annually to decay. In monetary terms losses of timber products 
as a result of decay are much larger than in standing timber, 
because of the high value of finished products and the labor 
cost of replacement. 
Expenditures for control of forest diseases averaged about $3 
million annually during the last decade. Most of these funds have 
been provided by the Federal Government, and the remainder from 
State and private sources, and have been expended primarily for 
control of the white-pine blister rust. 
Wind_and Miscellaneous Losses -- Timber 
Losses of standing timber from wind throw and miscellaneous 
causes, such as suppression and rodents, amount to an estimated 
300 million cubic feet annually, including 1.5 billion board feet 
of sawtimber. A large part of these losses is due to major blow- 
downs, such as the blowdown of Douglas-fir in 199-51. Part of 
the timber thus destroyed is salvaged. The value of the un- 
salvaged timber lost to wind and other causes, however, is roughly 
estimated at about $13 million annually. 
In many areas reduction in timber growth and yields as a result 
of rodents is far more serious than the direct loss of standing 
- 195 - 
