Characteristics of stands of P. tabulaeformis natural secondary forests.

*: stand mean ± within-stand S.D.**: Stand volume (M) and sample tree volume (V) was calculated by the following formula (1) and (2), respectively.(1)(2)Where M is the stand volume (m3·ha–1), ni is the number of i–th class of the sample tree, k is graded series (i = 1, 2, …, k), Gi is the i–th class of basal area of DBH (m2·ha–1), Vij and gij are the volume (m3) and basal area of DBH (m2) of j–th sample tree in i–th class, respectively. V is the sample tree volume (m3), gi is the central basal area (m2) of the i–th log, li is the length (m) of the i–th log, gn is the last basal area (m2) at the top of tree, l′ is the length (m) between the last basal area and the top of tree, n is the total number of logs.(1)(2)