茂兰喀斯特森林地上生物量林层格局及驱动因子.

Exploring the patterns of forest biomass distribution and its ecological drivers may shed light on our understanding of forest ecosystem functions, and provide useful knowledge for proper forest management. Here, in the karst forest of Maolan National Nature Reserve, we established sampling forest plots and estimated the forest aboveground biomass using allometric equations. By adopting statistical methods such as the paired t-test and linear mixed-effects models, we investigated the pattern of aboveground biomass distribution for the whole forest plot as well as separately for each forest stratum (i.e. overstory or understory). and explored the underlying abiotic and biotic driving factors. We found that the aboveground biomass of the overstory stratum was larger than that of the understory stratum; the total aboveground biomass of the forest was constrained only by the rock-bareness rate; however, when the forest was divided into different forest strata, we found that only the aboveground biomass of the overstory stratum was constrained by rock-bareness rate, and not the understory stratum. Furthermore, we found that the aboveground biomass of the two forest strata both varied with regards to topography, as shown by the larger overstory stratum at the slope when compared to the hilltop. The opposite trend was observed for the understory stratum; among the biotic factors, only the stem density exhibited positive influences on the aboveground biomass of the overstory and understory strata. These results imply that both abiotic and biotic factors regulate the aboveground biomass of Maolan karst forest, and whole forest level biomass analyses is limited in that the different patterns and drivers of aboveground biomass of different forest strata are overlooked. The findings demonstrate the importance of investigating each forest stratum separately when studying forest biomass patterns and the underlying drivers. In addition, these findings provide intellectual support for the management of Maolan karst forest. [ABSTRACT FROM AUTHOR]