an area in a mature forest that is to be cut. The felling sites used within a given year constitute the logging fund, which includes the felling areas cleared or partially cut for primary use. The form, shape, rotation sequence, and fixing dates are determined on the basis of the forest’s category, condition, and prevailing species. Felling sites are usually rectangular, sometimes divided into plots, and bounded by ranging rods and posts.
A clear felling site may be 50 m–1 km wide—for example, for pine species in Group 1 forests (forests that have protective, water-conservation, or other such value) it is set at 50 m, and for taiga forests in the raw-material centers for logging enterprises at 1 km. The annual forest exploitation norm for a given period is called the calculated felling, which is determined on the basis of the clearing methods, the forestry methods, and the character of forestry inventory operations.
With the clear-cutting forestry system widely used in the USSR, the calculated cutting area is selected through comparison of felling sites in terms of maturity, age, condition, and steady use. The felling site is determined according to maturity by separating the area of mature stands into one age class (20 years for coniferous species and ten for deciduous); according to age, by separating mature, overmature, and immature trees into two age classes; according to condition, by separating the area of the stands that require immediate cutting into the period designated for this case (five or ten years); and according to steady use, by separating the area of stands of an economic section into the corresponding cutting cycle.
There are other methods of calculating felling areas developed by Soviet foresters, such as N. P. Anuchin’s integral method and N. A. Moiseev’s balance method. Calculation makes it possible to schedule the fellings, to prevent depletion of forests, and to ensure the greatest possible exploitation.
The methods of clearing felling areas are governed by appropriate regulations. The methods of reforestation depend on the goals of forestry and on forest and plant conditions; they include retention of undergrowth, use of forest plantings, and noncutting of seedlings or subsequent reforestation.
REFERENCESAnuchin, N. P. Lesoustroistvo. Moscow, 1962.
Spravochnik lesnichego, 2nd ed. Moscow, 1965.
N. A. MOISEEV