FOREST BIOLOGY 209 



In the Puget Sound and Coeur d'Alene regions, fire hazards 

 differ in the stands very largely in proportion as the different species 

 tend to accumulate lichens and moss. The moss formations, when 

 dry, are exceedingly inflammable and scatter fire to long distances with 

 little wind. 



According to Darwin's famous reasoning, the crop of clover seed 

 was in inverse proportion to the percentage of blue-eyed cats in the 

 neighborhood. Bees were necessary to carry the pollen which fertilized 

 the seed. Mice, if too numerous, would destroy the bees. Cats would 

 keep the mice down. Blue-eyed cats had defective vision and could 

 not be good mousers. 



The usual conception of a forest is that of a host of trees of 

 various species and ages, contending more or less with each other and 

 against climatic conditions, but, on the whole, simply a lot of plants 

 growing along together. Such a conception is very seriously in error, 

 for a forest is no such thing. A forest is one of the most complex of 

 societies. In point of total population per unit of area, a forest is 

 one of the most densely inhabited areas in the world, numbering its 

 inhabitants by the billion per acre. As respects variety of inhabitants, 

 the forest also ranks very high — higher than the farm, the orchard, 

 the city, the prairie, perhaps the swamp. Certain water areas may 

 exceed the forest in both number and variety of inhabitants, but the 

 forest includes a great variety of types of fresh-water formations 

 and frequently the water-societies are intimately associated with those 

 of the forest or man's work in the forest. 



The inter-relations of the different forms of life and their inter- 

 actions and inter-dependencies are certainly intricate beyond the possi- 

 bility of present imagination. We know very little indeed about 

 biology, therefore little about the forests ; but we are beginning to 

 be able to form some conceptions of the situation, and it is already 

 obvious that Darwin selected a simple category. 



To the uninitiated, would there appear to be any probable relation 

 between an experiment in silk worms, automobiles, New England 

 forests, and real estate values? Would there appear a menace to 

 our most valuable tree species because of cheap labor and favorable 

 soil and weather conditions in Holland and the presence of wild goose- 

 berries and currant bushes scattered throughout the white-pine forests ? 

 Would one be. likely to assume that the fecundity and travel 

 habits of innocuous rodents might increase the cost of reestablishing 



