Re-Sprouting Characteristics Of 6 Tropical Tree Seedlings In Southern Yunnan Province

Six tropical woody species seedlings with different ecology habits were studied under two light and nutrient gradients on biomass allocation, structural characteristics, non-structure carbohydrate concentration and allocation in different organs and theirs effects on the subsequence re-sprouting ability after disturbance. The re-sprouting behaviors of shade tolerance climax tropical forest seedling--Barringtonia macrostachya was also studied under four different light gradients and under three different size of forest-gap in three different seasons. The results showed that:1.The shade-tolerance climax species B. macrostachya and Pterosperma lanceaefolium had higher re-sprouting capability than those of pioneers and the lime substrate specialization species. With the increase of shade tolerance, the re-sprouting ability also increased.2.Whether the shade tolerance climax species or the shade intolerance pioneer species, theirs re-sprouting capability were higher in high light than those in low light. With the decrease of shade tolerance, the capabilities to re-sprouting after disturbance were more sensitive to the decrease of light availability. Under the four light gradients, the re-sprouting ability of B. macrostachya increased with the increase of light availability.3.The shade-intolerance pioneer species Anthocephalus chinensis and Trema tomentosa all died after disturbance. The shade-intolerance species Macaranga denticulata had 20% re-sprouting rate in high-light*low-nutrient treatment, while subjectted a full mortality in other treatments. The other three shade-tolerance species had a higher re-sprouting ability in low nutrient treatment than that in high light, but the difference between nutrient gradients was not significant in low light.4.For all resprouters, high-light*low-nutrient treatment was the best treatment to promote their capability to re-sprouting.5.In the field, the cool season's disturbance induced highest re-sprouting ability, followed by dry season, while rainy season was lowest.6.For any season, the big forest gap individuals produced the highest number of leaf, maximum number of re-sprouted stem, maximum re-sprouted branch length hence theirs contribution to re-sprouting ability. Followed by small forest gap and under-story environment. The sprouting capability decreased with the decrease of ground light availability. 7.Most of the re-sprouting indexes studied were positively correlated with the original stump base diameter (OBD) and the individuals leaf area ratio (LAR) previous the disturbance, and negatively correlated with the percent of TNC allocation to root (RTNCa), root mass ratio (RMR) and root-crown mass ratio (R/C). While the concentration of TNC in all organs, leaf mass ratio (LMR), stem mass ratio (SMR) and the percent of TNC allocation to leaf and stem (STNCa, LTNCa) had no correlation with re-sprouting indexes.8.Number of re-sprouted leaf(NRL), total re-sprouted branch length(TRL), maximum re-sprouted branch length(MXRL), mean re-sprouted branch length(MEBL), total re-sprouted stem base diameter(TRBD) and maximum re-sprouted base diameter(MXBD) were significantly respond to most of the factors, which could affect the re-sprouting behaviors potentially. The correlation analysis results showed that number of re-sprouted branch (NRB), re-sprouting successful rate (RR) and maximum re-sprouted base diameter to original base diameter ratio (M/O-BD) had no correlation with most of those factors, which could infulence the re-spouting ability.