5. If the land is salable for $5 an acre or more it cannot be made to pay 6 per cent compound interest under the most favorable conditions, unless the stumpage received exceeds $6. At $5 stumpage and with reasonable taxation it will pay 5 per cent if it escapes fire.
6. Thirty cents an acre is apparently about the maximum annual carrying charge which will permit a 6 per cent profit, even with very high stumpage prices. Consequently, while present taxes on cut-over land are seldom prohibitive, there must be reasonable certainty that excessive increase will not occur.
The carrying charges shown in the second table cover both fire protection and taxes, as by reading the 15-cent line to include a 10-cent tax and a 5-cent fire patrol. The investment charge may be used to represent sale value only, or sale value plus any expense incurred at time of logging in order to secure reproduction, such as leaving salable material in seed trees, or planting. If desired, any owner may make a similar calculation on any other valuation better fitting his own situation. The table is not intended for universal use but merely as an illustration of how forest calculations may be made.
WHITE PINE
Too much space would be required to give a similar table for all western species, even were as good yield figures available. Roughly speaking, however, western white pine, under conditions thoroughly favorable to it, may be expected to make as good a yield as Douglas fir, and the above fir table will not be far off for it. A probably higher stumpage value should offset any lesser production.
HEMLOCK
Western hemlock is of somewhat, but not much, slower growth when coming in on open land as an even-aged stand. No yield table based on the same merchantable standards as the fir table quoted has been prepared, but the following is fairly safe to include all trees 14 inches in diameter used to 12 inches in the top: At 50 years, 2 M per acre; at 60 years, 22 M; at 70 years, 33 M; at 80 years, 40 M. The absence of a 40-year figure, and the sudden jump between 50 and 60 years, is because very few hemlock trees reach 14 inches at 50 years, but a large number of 12 and 13-inch trees pass into that class during the ten years following. Any yield figures for an even-aged forest show a similar jump at the point where the stand as a whole reaches the determined minimum merchantable size. For the same reason these hemlock figures are not very far less promising than those given for fir, for at corresponding ages the latter include 12 and 13-inch trees and all trees are considered merchantable to a top diameter of 8 inches.
SPRUCE
Since no systematic study of Sitka spruce second growth has been made, it can only be predicted from knowledge of its habits that while in favorable situation it will yield as heavily as Douglas fir, in other localities its growth in early life is slower and less regular, making it less likely to produce a good crop before the carrying charges become burdensome. If this proves true, taxation rates and land values will be extremely important factors, offset to some degree by a smaller fire hazard and the probability of high stumpage.