Study on shooting rhythm of Fargesia decurvata under different canopy conditions

We studied the shooting rhythm of Fargesia decurvata J. L. Lu under three different forest canopies (i.e., deciduous broad-leaved forest, evergreen-deciduous broad-leaved mixed forest, and evergreen broad-leaved forest) in Jinfo Mountain National Nature Reserve. Results showed that (1) the deciduous broad-leaved forest and evergreen-deciduous broad-leaved mixed forest exhibited an early shooting time, long shooting period (~110 days), high shooting number, and high shooting rate. In contrast, the evergreen broad-leaved forest exhibited a late shooting time, short shooting period (~88 days), low shooting number, and low shooting rate. The highest shooting number was observed in the evergreen-deciduous broad-leaved mixed forest. (2) The F. decurvata shooting period could be divided into three stages (i.e., early, peak, and late) and differed for each forest type. In evergreen-deciduous broad-leaved mixed forest, F. decurvata entered the peak stage earliest, followed by the deciduous broad-leaved forest and evergreen broad-leaved forest. The peak stage of bamboo shooting was also the peak period of shoot degradation. The rate of shoot degradation was highest in the evergreen-deciduous broad-leaved mixed forest, followed by the deciduous broad-leaved forest and evergreen broad-leaved forest. (3) In the same canopy environment, there were no significant differences in the basal diameter of bamboo shoots during the different periods. The basal diameters of the bamboo shoots in the deciduous broad-leaved forest and evergreen-deciduous broad-leaved mixed forest showed no significant differences in the shooting period but were significantly larger than that in the evergreen broad-leaved forest (P < 0.05). (4) The height growth process for bamboo shoots was completed after ~80 days and followed a logistic curve with a "slow-fast-slow" growth trend. Furthermore, the height growth rate of the bamboo shoots exhibited significant differences under the different canopy conditions and followed the pattern of evergreen-deciduous broad-leaved mixed forest > deciduous broad-leaved forest > evergreen broad-leaved forest. (5) Clonal propagation and bamboo density were closely correlated. With the increase in bamboo density in the forest canopy, the shooting number increased, and the rate of mature bamboo shoots decreased. Thus, this study suggests that F. decurvata development was best in the evergreen-deciduous broad-leaved mixed forest and worst in the evergreen broad-leaved forest. In addition, population density played an important role in regulating bamboo regeneration and development.