CHAPTER III
FORESTRY AND THE FOREST
ELEMENTARY PRINCIPLES OF FOREST GROWTH
Whether the lumberman's judgment of economic influences leads him to be optimistic or otherwise as to the profit of forestry in general, he is most interested in the particular forest with which he has to deal. He can neither accept nor dismiss the proposition intelligently, much less put his ideas into actual practice, without knowing something of the capability of his land to respond to his effort. "What methods are best, what will they cost, and what will be the result?" are questions which arise at the very outset. They lead at once into the domain of technical forestry.
With us forestry has not been practiced long enough to furnish demonstrated examples with which to answer such questions. We can, however, profit by experience gained elsewhere, for the laws which govern tree life are as universal as those which govern the life of men and animals. In dealing with new species and new environments we have no great difficulty in judging their future from their past, which lies written plainly for those who care to study it.
While to some extent trees require elements obtainable only from the soil, they are more independent in this respect than most other forms of vegetation. Soil influences forest trees mainly by its physical character, especially as this determines the moisture contents. Very little nourishment is actually taken out of the soil for, as someone has said, wood is nothing but air solidified by sunshine. A tree's immense and complicated foliage system is the laboratory with which it effects this transformation.
Since air exists everywhere and the chemical quality of the soil is comparatively unimportant, the requirements of different species for light, heat and moisture are what mainly determine their distribution and habits of growth. And since heat and moisture are largely climatic factors and fairly uniform in given localities, it follows that the demand of a species upon light may practically fix its habits and possibilities in those localities. The very great variance of species in light requirement accounts to a large extent for the composition of most primeval forests. It is of peculiar importance in the management of forests by man because he cannot control it as he may be able to control some of the other agencies which affected the primeval forest, such as fire or seed supply.
SELECTION FORESTS
It would be unprofitable to discuss here all the many methods of forest management which have proved to be best, technically, for given species and combinations of species. Where market and transportation facilities are highly favorable, as in Europe, the timber owner can adopt the method which will bring the best results, but here he has no such choice. He can but bear in mind certain fundamental principles, uniformly applicable to large areas for considerable periods of time. Roughly, however, our Western forests can be classified by their adaptability to the two directly opposite systems, known as clean cutting and selection cutting, of which almost all methods are modifications.