基于连续清查数据的浙江省乔木林龄组结构变化动态

Dynamics of Change in Age Group Structure of Arbor Forests in Zhejiang Province Based on Continuous Inventory Data

以1979—2019年间的浙江省历次国家森林资源连续清查和省级森林资源年度监测数据为依据,采用统计比较、平衡率分析、面积转移推算等方法,对浙江省40年的乔木林龄组结构变化情况进行分析研究,并预测之后10年(2020—2029年)的发展动态。结果表明:1)40年间,浙江省乔木林龄组结构变化可明显地分成两个阶段,1979年至20世纪末是乔木林面积快速增长期,龄组平衡率从0.464小幅缓增到0.546,龄组结构的优化不是主要演替特征,进入21世纪后,乔木林面积呈滞增状态,龄组平衡率从0.546提高到0.758,龄组结构优化成为主要演替特征;2)浙江省乔木林的龄组结构目前已接近较理想状态,具有充分培育森林资源的潜力,预测至2029年能达到理想状态;3)目前,浙江省乔木林存在着某个树种相对幼龄,另一个树种相对老龄而产生林分总体年龄互补效应,应注意因林分年龄结构总体较佳而掩盖的分树种年龄结构不均衡的情况。根据浙江省乔木林龄组结构现状和可持续经营的目标导向,提出优化龄组结构的措施建议,以期促进森林资源质量和固碳增汇能力的提升。

Based on the data from successive national forest resources inventories and annual monitoring of provincial forest resources in Zhejiang Province during 1979-2019,we analyzed the changes in the age group structure of arbor forests in Zhejiang Province over the past 40 years and predicted the development in the next 10 years by adopting methods such as statistical comparisons,analysis of the balance rate,and projections of area transfer.The results show that:1)During the 40 years,the changes in the age group structure of arbor forests in Zhejiang Province can be obviously divided into two phases.From 1979 to the end of the 20th century,there was a period of rapid growth in the area of arbor forests,and the age group equilibrium rate increased from 0.464 to 0.546,and the optimization of the age group structure was not the main successional feature;after entering the 21st century,the area of arbor forests was stagnant,and the age group equilibrium rate increased from 0.546 to 0.758,the optimization of age group structure has become the main successional feature;2)The age group structure of arbor forests in Zhejiang Province is now close to an ideal state,with the potential for forest resources to be fully cultivated,and it is predicted that it will reach an ideal state by 2029;3)At present,the arbor forests in Zhejiang Province have the problem of the overall age complementary effect of the stand,which means a relatively young age of one species and the relatively old age of another.It should be noted that the overall better age structure of the stand may mask the uneven age structure of individual species.Based on the current status of the age structure of arbor forests in Zhejiang Province and the target orientation of sustainable management,measures to optimize the age structure are proposed,with a view to promoting the improvement of the quality of forest resources and the capacity of carbon sequestration and sink enhancement.