Effects of tree age and waterlogging duration on the form factors of eastern cottonwood (Populus deltoides Bartr. ex Marsh.)

Stem form is the short name of the tree trunk shape. Stem form determines the quantity and quality of trunk volume, and affects forest timber volume and stand merchantable volume. Based on Populus deltoides Bartr. ex Marsh. in the Dongting Lake region of Hunan Province in China, changes in the breast-height form factor (f_1.3) and experimental form factor (f_a) under different waterlogging durations and stand ages were analyzed using the two-way analysis of variance (ANOVA). The results showed that the differences in waterlogging duration for f_1.3 were not significant, but were significant for f_a. Tree age has significant effects on f_1.3 and f_a. In addition, the f_a of P. deltoides grown in stands with a waterlogging duration of 24 days and 33 days were slightly larger than the other three 50, 64, 86 days, which indicated that trees grown in these stands (24, 33 days) had larger tree volumes. In addition, the waterlogging duration of longer than 86 days was not suitable for the growth of P. deltoides.