Evaluating stand growth state by potential density of stocking

ObjectiveStand growth is a direct reflection of stand vitality, density of stocking is one of the most commonly used indices to reflect the degree of closeness and its growth status in a stand. Accurate calculation of standard basal area is the key to calculate density of stocking, but it has poor availability and applicability because of the difficulty to distinguish standard stand among all stands of an area. exploring an alternative index is an effective way to solve this problem. Therefore, the purpose of this study is to find the new index.

MethodThe potential productivity of a forest is finite under certain site conditions. Based on the Law of Constant Ultimate Capacity, in this study, we analyzed Cunninghamia lanceolata plantations under continuous monitoring with its growth process data all in readiness, with Cunninghamia lanceolata standard tables, which compiled in 1989 as cross reference. The potential maximum basal area of the stand was expressed by the product of the average basal area of a certain percentage of larger individuals and the total number of trees in the stand. Comparing the proportion from 50%−80% at 5% interval, we seek to find the ratio when the deviation rate between the potential maximum basal area and standard basal area was at its minimal value, and analyzed the applicability of potential maximum basal area in natural forests on this basis.

Resultthe results suggested when the proportion was 70%, the deviation rate between the potential maximum basal area and the standard basal area of all test plots was about ± 10%, and the difference between the potential density of stocking and the density of stocking was at its minimal value. Furthermore, in order to test the applicability to natural forests, statistical analysis indicated that there was a significant linear relationship between the basal area with 70% as the larger trees and the stand basal area in the natural forest. The results showed that the potential density of stocking of a stand could be calculated by the product of the average basal area with 70% as the larger trees and the total number of trees.

ConclusionThe potential maximum stand basal area could be expressed as the product of the average basal area with 70% as the larger trees and the total number of trees. The potential density of stocking, as an alternative index, can replace the density of stocking to characterize density and growth status of a stand.