. Report upon the forestry investigations of the U. S. Department of agriculture. 1877-1898. Forests and forestry. 244 FORESTRY INVESTIGATIONS U. S. DEPARTMENT OF AGRICULTURE. winds makes it desirable to have the fellings progress from the south and west toward north and east. Altogether it will have become apparent that the distribution of successive fellings is an important matter, not only from the standpoint of regulated administration, but also of successful culture. In the accompanying map (PL XXXII) we have attempted to give an idea of the matter on which a "manager's map" is
. Report upon the forestry investigations of the U. S. Department of agriculture. 1877-1898. Forests and forestry. 244 FORESTRY INVESTIGATIONS U. S. DEPARTMENT OF AGRICULTURE. winds makes it desirable to have the fellings progress from the south and west toward north and east. Altogether it will have become apparent that the distribution of successive fellings is an important matter, not only from the standpoint of regulated administration, but also of successful culture. In the accompanying map (PL XXXII) we have attempted to give an idea of the matter on which a "manager's map" is constructed, and how ideally in a forest of tbe plain the arrangement of age classes would appear when the forest regulation is perfected. YIELD CALCULATIONS. When the distribution of areas has been effected in accordance with the considerations set forth, the yield calculations are made. These are computed after careful measurements and by various methods of calculation, which have been developed after much experience during more than one hundred years. Since the different compartments are cut at different times, not only the present "stock on HUNDRED CUBIC FT. 180 160 140 120 100 80 60 40 HUNDRED CUBIC FT. 180 160 20 0 w 0 10 20 30 40 50 60 70 80 90 100 110 Fig. 24 —Diagram showing comparative progress of yields of spruce, fir, pine, and boecli on best and pooiest site < Usses. hand" needs to be measured, but also the accretion for each age class from tbe present to the middle of the period in which it is to be utilized as to total quantity (decreasing in arithmetical proportion as the stock on hand is diminished by fellings), when by adding the two quantities and dividing the total by the number of years in the rotation or time of regulation the equalized yearly quota to be utilized, or "felling budget" (Haubarkeitsertrag or etat), can be calculated. The determination of existing stock is made by measuring diameter breast high by mean
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectforestsandforestry
