. Cyclopedia of farm crops. Farm produce; Agriculture. Fig. 472. Dense stand of young hard-woods ia need of moderate thinning. falling trees do little injury, they do not lodge so that they can not be brought down with a twist of a cant-hook, and the remaining trees do not blow down. The principal object of thinning is to preserve the balance between height-growth and diame- ter-growth of the trees that are to form the final stand. in volume is determined by height- and diameter-growth. If the trees stand too close together, height-growth will be in excess, followed by a reduction in
. Cyclopedia of farm crops. Farm produce; Agriculture. Fig. 472. Dense stand of young hard-woods ia need of moderate thinning. falling trees do little injury, they do not lodge so that they can not be brought down with a twist of a cant-hook, and the remaining trees do not blow down. The principal object of thinning is to preserve the balance between height-growth and diame- ter-growth of the trees that are to form the final stand. in volume is determined by height- and diameter-growth. If the trees stand too close together, height-growth will be in excess, followed by a reduction in vitality. If the trees stand too far apart, diameter-growth will be in excess, accompanied by large side limbs. In either case the quantity and quality of the timber will be affected. Therefore, by preserving the balance between the two, an acre of land is made to produce more and better lumber in a given period of time. The extent to which a closed stand may be opened depends on several conditions. The kind or kinds of tree that compose the stand, the nature of the soil, the character of the undergrowth, the purpose for which the timber is grown, all play a part in determining the degree of thinning. This is one of the many matters in forestry that cannot be reduced to a rule, but must be based on a study of each woodlot. There are, however, several con- siderations which indicate the extent to which a woodlot may be thinned. The classes into which trees in a closed stand gradually become separated, in the course of their struggle for existence, are of assistance in selecting trees for removal. Four classes are usually distinguished : (1) dominant, (2) intermediate, (3) suppressed, and (4) dead. Dominant trees are those that have their crowns in the iight; they have kept ahead of the oth'ers in height-growth. Intermediate trees are those that .still have their crowns in the light, but are somewhat backward, and are destined to become suppressed in the near future.
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