240 ANNUAL, REPORTS OF DEPARTMENT OF AGRICULTURE. 



ness with which forest fires burn. Low humidity means danger, 

 but abundant moisture in the air acts on a fire like a wet blanket. 

 Tests made this season on forest fires in the Pacific Northwest have 

 predicted with surprising accuracy the rising or falling violence of 

 the fixes and have made possible increased efficiency of attack. A 

 great difficulty in large-scale fire fighting has come from our inability 

 to recognize dangerous conditions until they have actually arrived 

 and oftentimes brought disaster. The prediction of these oncoming 

 emergencies, even a few hours ahead, will permit more effective 

 mobilizing to meet them. 



FOREST PRODUCTS. 



If it is folly to grow timber merely to be burnt, it is equal folly to 

 grow it to be wasted by ignorance or indifference. Nowhere in Arner- 

 ican life is waste more conspicuous than in our forests and forest 

 products. In all the stages of manufacture — the woods, the sawmill, 

 the wood-using factories, the building trades, wherever wood is used — 

 there is waste, appalling in its aggregate. American business has 

 begun to see the vital importance of better methods of manufacturing 

 and using wood ; it recognizes that wood saved is equivalent to wood 

 grown; it perceives that high prices and growing scarcity must 

 soon make economy imperative; and it desires to be shown how 

 waste may be curtailed. The work of the Forest Products Labora- 

 tory is accomplishing this. In a word, its task is to do by saving 

 what silviculture does by timber-growing. 



The year was one of the most successful in the history of the 

 Forest iProducts Laboratory. The scope of the fundamental research 

 was enlarged, its application increased, cooperative work with 

 industrial agencies extended, and new methods of disseminating 

 results developed. This involved a larger personnel than for any 

 previous year save during the war crisis. 



The annual production of lumber and structural timbers for gen- 

 eral building purposes reaches a value of nearly a billion dollars, 

 and its most efficient production and utilization present many 

 problems, the study of which goes on year after year. The study of 

 the strength of timbers is a case in point. The object sought is to 

 reduce waste by developing more accurate knowledge of the limits 

 and causes of strength variability, so that less allowance need be 

 made to insure the necessary margin of safety. A series of studies 

 completed during the year show how, with proper selection, higher 

 working stresses and hence smaller timbers of Douglas fir, western 

 yellow pine, and hemlock can be used than in the current practice. 

 An exhaustive piece of research which will extend over four years is 

 under way on large columns of southern pine and Douglas fir; it 

 has already indfcated that pieces with more knots than have been 

 allowed can be used and that grading rules for their selection can be 

 improved. 



The laboratory is dealing on a comprehensive scale, yet with 

 elaboration and painstaking accuracy, with the whole field of use of 

 wood. Nor is its work confined to finding out how wood can be saved, 

 or better used. A large part of its effort is given to bringing to pass 

 the industrial application of results. Representatives of the labora- 

 tory have taken an active part in the movement for standardizing 



