In forests managed systematically for continuous timber crops, the growing stock of wood usually amounts to 75 or 80 per cent of the total invest ment. For this reason, the raising of continuous crops of large timber for construction purposes can be done advantageously only on considerable forest areas, with a large capital tied up perma nently in young, growing trees. The owner of a small woodlot will inevitaby find it most profitable to raise chiefly fire-wood, mine props, fence-posts, ties, and similar timber products that require a comparatively short time for their production, using for that purpose only quick-growing species, or managing his forest as sprouts which possess at an early age a capacity for more rapid growth than trees started from seed. The fact, however, that the woodlot, as a rule, is not an independent enterprise, but an adjunct to farming or some other business, enables its owner to manage it not on a strictly financial basis, because of the many bene fits which he derives from it indirectly, in the form of windbreak or shelter to his cattle, in addition to the products raised for his own home con sumption.
There are also purely technical reasons which make extensive forest tracts better adapted for raising timber crops than small woodlots would be. In a large forest the proper distribution of trees of various ages, which is so essential to con tinuous wood-cropping, can be more easily attained; on a large tract the main body of forest, being well protected by the outer rows of trees on the edge of the forest, suffers less from wind than small woodlots, which are frequently exposed to the sweep of gales; in a large forest there are always more seed trees and more seed on hand, and the conditions for starting a new crop are generally more favorable than on small tracts.
Timber crops, unlike farm crops, can not be managed very intensively. Intensive industries are characterized by their capacity for absorbing a considerable amount of labor ; and forestry, with the exception of harvesting timber crops, offers, as has already been pointed out, but little opportunity for the application of labor. Besides, forests grow, as a rule, on the poorest soils and roughest situa tions, which makes any intensive management financially unprofitable because of the expenditure being out of proportion to the possible gain in net returns. If to this be added the fact that it takes 100 to 150 years for trees to reach large dimen sions, and therefore only or of the total forest area can be cut over every year, if annual sustained yields of large timber are desired, the need of vast forest areas for continuous wood-pro duction becomes self-evident.
All this taken together emphasizes the impor tance of capital as a factor in the production of wood crops, and has even led to designating for estry as a "capital intensive" industry in distinc tion from agriculture which requires a relatively smaller fixed capital but a larger amount of labor.
The three main factors of forest production may be thus arranged in the order of their importance : Nature, capital and labor.
Literature.
B. E. Fernow, Economics of Forestry, Thomas Y. Crowell & Co., 1902; John Nisbet, The Forester, Vol. I, William Blackwood & Sons, Edinburgh and London, 1905 ; Gifford Pinchot, A Primer of Fores try, Parts I and II, Bulletin 24, Forest Service, United States Department of Agriculture ; William Schlich, A Manual of Forestry, Vol. I, Introduction to Forestry, London, Bradbury, Agnew & Co., 1896 ; " Forsten," by M. Enders in "Handworterbuch der Staatswissenschaften," edited by Conrad, Elster, Lexis and Lcenig, Jena, 1900.
Raising the Timber Crop.
Trees may be divided into two classes : (1) Those that are called shade-enduring or tolerant, and (2) those that are light-de manding or intolerant. These characteristics of trees are of great importance in considering the subject of the renewal of growth on forest lands, or even in the matter of planting land that is not yet in forest. While it is not an absolute rule that tolerant trees have a thick mass of foliage, and intolerant have open foliage, yet this statement is so generally true that when this characteristic is known it serves as a very reliable indication. Among our tolerant trees may be mentioned the spruce, balsam, white cedar, red cedar, oak, hornbeam and hard maple.
Among our intolerant species are the poplar, cottonwood, willow, soft maple, birch and jack and red pine.
The ideal forest is one that might be called a two-storied affair, that is, having an in tolerant species above and a tolerant species below, much the same as in a crop of corn, / where we may have pumpkins growing under the shade of the corn. Trees protect one an other and are mutually helpful, and as a rule are most hardy when grown in groups. Trees also interfere with one another, and in their struggle for light and soil privileges the weaker trees are often suppressed and per haps all of them are injured. On the other hand, crowding forces them to t ake on an upward growth and kills out the lower branches, which is necessary for the production of good timber. Trees that grow in the open have side branches and make inferior lumber that is full of knots.