graves: place of forestry among sciences 53 



Observations of the effect of climate upon forest growth natur- 

 ally brought out facts with regard to the effect of forests upon 

 climate, soil and other physical factors and led to the develop- 

 ment of a special branch of meteorology, known as forest mete- 

 orology, in which the foresters have taken a prominent part. 

 While there are some phases in forest meteorology which still 

 allow room for disagreement, some relationships established by 

 foresters are widely accepted. One of these is the effect which 

 forests have upon local climate, especially that of the area they 

 occupy and of contiguous areas. Every farmer who plants a 

 windbreak knows and takes advantage of this influence. Another 

 relation is that between the forest and the circulation of water on 

 and in the ground, a relation which plays such an important part 

 in the regimen of streams. Still a third one, as yet beyond the 

 possibility of a.bsolute proof, is the effect of forests in level coun- 

 tries, in the path of prevailing winds, upon the humidity and 

 temperature of far-distant regions lying in their lee. 



If in the field of botany the forester has contributed to the 

 progress of botanical geography and in the realm of meteorology 

 has opened new fields of investigation, his influence in wood 

 technology has been in changing entirely the attitude of engineers, 

 physicists and chemists in handling wood products. The methods 

 of studying the physical, mechanical and chemical properties of 

 wood were, of course, those used in engineering by chemists and 

 physicists; but the forester has shown that wood, unlike steel, 

 concrete, or other structural material, is subject to altogether 

 different laws. Wood, he has shown, is not a homogeneous 

 product, but is greatly influenced by the conditions in the stand 

 from which it comes. Were it not, therefore, that mechanical 

 properties can be tied up with some definite forest conditions and 

 correlated with some readily visible expression of tree growth, 

 such as the number of rings per inch or the specific gravity of the 

 wood, timber would be too much of an indefinite quantity for 

 architects and other users of wood to handle with perfect safety. 

 To find such a relation is just what the foresters have been at- 

 tempting to do, and most of the studies of the strength of wood 

 have been with the view of establishing certain relations between 



