武夷山毛竹林生物量异速生长系数的海拔分异及其影响因子

Biomass estimation is mainly based on the plant allometry, of which coefficients (i.e., parameters) vary from site to site and climatic conditions (e.g., temperature and precipitation). Thus the changes in biomass allometric coefficients result in biomass estimation with a great uncertainty. To clarify the variation of biomass allometric coefficients along the different gradients like elevation, water and heat, therefore, has become one of the key elements in reducing the uncertainty and improving its prediction. During this project, Moso bamboo stands were established along the altitudinal gradient in Wuyi Mountain, Fujian Province. Plot survey and laboratory analysis were conducted to explore the altitudinal differentiation in biomass allometric coefficients of Moso bamboo and their influencing factors. We also verified whether the scaling coefficients in the two biomass allometric equations are significantly differet from 8/3 and 2/3, respectively. This project is of a great significance for a better understanding of biomass allometry, the interaction between Moso bamboo and its environmental conditions, and will also contribute to estimating biomass of Moso bamboo forest accurately and thus mitigate the climate change.

林木和森林生物量的估算主要依靠异速生长关系模型，然而异速生长模型参数常因地点和气候条件等的改变而发生变化。澄清异速生长模型参数沿着不同梯度发生的地理分异规律及其影响因子，可以提高生物量估算和其预测的准确性。因此，本项目选择有海拔梯度的福建武夷山毛竹林为研究对象，通过分别对7个梯度的毛竹林分进行每木检尺和生物量测定，结合室内土壤理化性质分析，揭示毛竹生物量估算模型参数沿着海拔梯度的分异规律，并找出其变化的主导因子，同时验证代谢理论的推论。该项目的实施，有助于加深对异速生长关系和毛竹与其环境相互响应的机制理解，同时对于进一步提高竹林碳汇的预测准确性和发挥竹林在应对气候变化过程中的作用都具有重要的意义。

林木和森林生物量的估算主要依靠异速生长关系模型，澄清异速生长模型参数沿着不同梯度发生的地理分异规律及其影响因子，能够减小模型误差、提高生物量估算和其预测的准确性。本项目选择有海拔梯度的福建武夷山北麓南坡毛竹林为研究对象，通过分别对7 个梯度的毛竹林分进行每木检尺和生物量测定，结合室内土壤理化性质分析，揭示毛竹生物量估算模型参数沿着海拔梯度的分异规律，并找出其变化的主导因子，同时验证代谢理论的推论。.通过每竹检尺和野外取样，建立7个梯度（400 m、550 m、700 m、850 m、950 m、1200 m和1330 m）的生物量-胸径、竹高-胸径的模型，通过优化发现，幂函数为最优的估算模型。海拔对于毛竹林平均胸径、立竹高、立竹度、叶面积、不同器官的生物量和根茎比具有明显的影响（P<0.001），随着海拔升高土壤有机碳密度具有明显的增加趋势(P = 0.004)，竹林凋落物不受海拔的影响。简约主轴回归分析结果表明，毛竹生物量-胸径、竹高-胸径两组异速生长关系的系数不遵循代谢理论的推论，而且两组系数沿着海拔具有不明显的变化规律。相关分析表明，竹高-胸径的异速生长关系系数受到土壤湿度和竹子地下器官生物量的制约, 生物量-胸径相关系数与林分结构、土壤理化因子相关性不明显。