基于森林健康视角的北长山岛人工林生物量

以山东省长岛县北长山岛为研究区，通过现场调查、数学模型和3S技术，分析人工林生物量的总量（全部生物量）、存量（活树生物量）、失量（死树生物量）和存量失量比，并探讨生物量的影响因子.结果显示：（1）北长山岛人工林生物量总量共5.88万t，均值为145.8t/hm²，高于全国和山东省的平均水平；生物量存量共3.79万t，失量共2.09万t，其均值分别为93.9t/hm²和51.9t/hm²，森林健康问题已经成为影响北长山岛人工林生物量的重要因素.（2）随着林分密度的增加，生物量总量和存量呈现先上升后下降的趋势，失量持续上升，存量失量比则不断下降；随着胸径的增大，黑松的存量失量比逐渐减小，刺槐则相反；NDVI与生物量总量、存量和存量失量比呈显著正相关，与失量呈显著负相关.（3）存量失量比与坡向、土壤含水率、全磷和总氮呈显著正相关，与海拔、坡度、含盐量和全钾呈显著负相关，与坡位、pH值和总碳关系不明显.

The plantation biomass on Beichangshan Island based on forest health

In this study, Beichangshan Island in Changdao County of Shandong Province was used as the research area. On the basis of field investigation, the methods of mathematic model and 3S technology were adopted. The plantation biomass was classified as total biomass (TB), existent biomass (EB), and lost biomass (LB), which represents the biomasses of all trees, living trees and dead trees, respectively. The ratio of existent biomass to lost biomass (EB/LB) was used to describe the relationship between different components of biomass and to reflect the plantation health condition from a new perspective. Then, the spatial distribution patterns and the impacting factors of plantation biomass were discussed. The results revealed that TB of plantation on Beichangshan Island summed to 58.8 kt, with the average value of 145.8t/hm², which was higher than that of the whole country and Shandong Province. EB summed to 37.9 kt with the average value of 93.9t/hm², and LB summed to 20.9 kt with the average value of 51.9t/hm², indicating that the health condition of plantation has been an important factor impacting the plantation biomass. With the increase in stand density, both TB and EB firstly increased and then decreased, while LB kept an increasing trend, whereas EB/LB showed the opposite trend. The diameter at breast height (DBH) of 10~20cm accounted for the most biomass, and with the increase in DBH, EB/LB of Pinus thunbergii tended to decrease, while EB/LB of Robinia pseudoacacia showed the opposite trend. The normalized difference vegetation index (NDVI) was significantly positively correlated with TB, EB and EB/LB, but negatively correlated with LB. EB/LB was significantly positively correlated with slope aspect, soil moisture content, total phosphorus and total nitrogen but negatively correlated with altitude, slope, soil salinity and total potassium, and had no significant correlations with slope position, soil pH and total carbon.