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›› 1964, Vol. 9 ›› Issue (1): 1-31.

• 论文及研究报告 •     Next Articles

FOREST REGENERATION SURVEY AND ITS STANDARD

Huang Zhongli   

  1. Institute of Forest Science, Academy of Forest Science
  • Received:1900-01-01 Revised:1900-01-01 Online:1965-10-01 Published:1965-10-01

Abstract: The standards of forest regeneration survey of Prof. V. G. Nescherov. USSR and many authors of other country are compared and studied. Some of them take the ideal of deriving regeneration standards from yield tables as the basis of their studies. It is necessary to take the number of trees per hectare of different age classes in yield tables as a reference of projecting the standards,of forest regeneration survey for various types and site classes of different tree species. Plot the number of trees over the average diameter on the double logarithmic paper it is found that the curve appearing negative and slightly convex upward which superposes the mortality of fully stocked stands. As the horizontal line on above graph denotes no decreasing of number of trees with increasing average diameter, the most probable case of mortality after forest regeneration will follow the equal divided line of the angle made by the horizontal line and that curve. Take 5 cm, 10 cm, 15 cm and 20 cm as the predicting average diameters of fully stocked stands, four parallels can be drawn from corresponding points on that curve with the same slope as the divided line of that angle. These four parallels cut the area under curve into 5 parts which might represent 5 grades of forest regeneration. Therefore the predicting average age, average diameter and average number of trees per hectare for the regenerated stands for each grade can be figured out. According to above method, the author develops 216 allometric equations and corresponding standards of forest regeneration survey for 54 site classes or types of main tree species in China that have yield tables already constructed. The author adopts the degree of stocking as a proper index of seedling distribution. The percent of plot which incur seedling on a series of plots by systematic sampling will denote the degree of stocking. It is proposed that the small plot should be circular in. shape and its area should be approximately equal to the average crown projection area of the premature trees of various species. As the stands grow old, the crown canopies begin to close up, the degree of stocking becomes greater and greater till 100% or more. The calculating measure of degree of stocking of regenerated stands must be concord with that old stands though they are based upon different mensurational elements so that the stands can be managed and thinned in a unified way. The principle and method of calculating the degree of stocking for multiple species and for stands with different mensurational basis are also mentioned. Finally, proposals and betterments are given to the method of survey for various ways of forest regeneration.