汶川地震四川重灾区森林景观变迁及间接损失研究

采用遥感技术获取林地次生山地灾害信息,结合灾前森林资源、植被类型等专题数据,通过空间叠加与综合分析,完成了汶川地震四川重灾区森林植被景观变迁及间接损失研究.结果表明:(1)地震诱发林地次生山地灾害11 808处,面积32.87万hm~2,占重灾区林地面积的4.66%;以滑坡、崩塌类型摧毁林地最为严重,这两类灾害损毁林地面积占林地损毁总面积的90%;不同森林类型中,阔叶林、灌丛地、针叶林成为林地的主要受灾对象,以阔叶林受灾损失面积最大.为13.63万hm~2,占受损面积的41.46%.(2)地震灾害造成该区林分损毁面积21.26万hm~2,导致森林覆盖率由44.51%下降为42.64%,降低了1.87%;汶川地震灾区森林植被损毁后,在维护森林资源稳定性与涵养水源、保育土壤、固碳释氧、生物多样性保护、森林游憩等生态系统服务功能方面的间接损失共计1 830.96亿元.

Study on Variation of Forest Landscape and Indirect Loss in Sichuan Seriously Disaster Area by Wenchuan Earthquake

The information of forestland following mountain hazards was acquired based on the interpretation of remote sensing images and specialty data of forest resources and plant types before disaster, variation of forest landscape and indirect loss going with loss of forest plants were evaluated by spatial overlay analysis. The results showed:(1) There were 11 808 traces of mountains hazards brought by earthquakes,the traces of mountains hazards covered 32. 87× 10~4 hm~2 ,or 4. 66% of the region's forestland area;the hazard area of landslide and landslip was most extensive and covered 90% of forestland loss area; the three types of broad-leaf forest,shrub and coniferous forest were destroyed seriously, the loss area of broad-leaf forestland covered 13. 63×10~4 hm~2 ,or 41. 46% of forestland loss area. (2) The loss area of woodland by earthquakes covered 21. 26~10~4 hm~2 ,the percentage of forest cover in the region descended from 44. 54% to 42. 64%,a fall of 1. 87 percentage points;upon the destruction of the forestland,the following indirect loss reached to 183. 096 thousand million,including maintain forest resources stability and ecology function of water conservation,soil conservation,carbon fixation and oxygen release,biodiversity conservation,forest recreation.