潮白河流域林地转化及森林生态服务价值动态分析

Dynamic analysis of forest land conversion and forest ecological services value in Chaobai River Basin

为实现绿色GDP核算提供基础,在构建评价指标的基础上,利用4期土地利用数据基于时空马尔科夫链模型对潮白河流域森林生态服务价值动态变化进行了评估。结果表明:该流域前4期林地间逐期转化表现为方式由简单到复杂,频数由小到大;而林地与其他土地利用类型间逐期转化表现相反且呈各土地利用类型均向林地转化趋势。1987、2000、2008年以及预测的2020、2030和2040年森林总面积较1972年分别增加5.4%、36.9%、46.7%、46.1%、46.0%和46.0%,森林生态服务总价值较1972年分别增加6.2%、55.5%、71.2%、72.1%、72.9%和73.6%。阔叶林和涵养水源项占生态服务总价值比例最高,混交林所占比例显著递增。针叶林、阔叶林和混交林分别在1972-1987年、1988-2000年和2001-2040年期间森林生态价值变化中起主导作用。说明单位面积森林生态服务价值逐期增加,森林结构得到优化。

Through building an evaluation index, the ecological services value of forests was quantified and evaluated dynamically in Chaobai River Basin with four periods’ land-use data and the spatio-temporal Markov chains model to realize green GDP accounting. The results showed that all types of land-use turned to forest land gradually in a whole trend, with the forest land transformation method changing from simple to complex, the frequency changing from small to large, while forest land and other land-use types showed the opposite process of transformation during the four periods from 1972 to 2008 in Chaobai River Basin. The total forest area in 1987, 2000, 2008 increased by 5.4%, 36.9%, 46.7%, and predicted area in 2020, 2030, 2040 would increase by 46.1%, 46.0%, 46.0% compared with that in 1972. The total value of forest ecosystem services increased by 6.2%, 55.5%, 71.2% and 72.1%, 72.9%, 73.6% than that in 1972. Among all the functions, water conservation accounted for the highest percentage of the total value of ecological services, as well as the broad-leaved forests among all the types of forests; the proportion of mixed forests increased remarkably. Coniferous, broadleaf and mixed forests play a dominant role in the changes of the forest ecological value in 1972–1987, 1988–2000 and 2001–2040, respectively. The forest ecosystem service value per unit area has increased by periods and forest structure has got optimized.