冰雪灾害造成森林乔木层C贮量损失评估与分析——以福建省长汀县为例

Appraisal and Analysis on the Loss of Carbon Storage at Arbor Stratum of Forest Caused by Ice-Snow Disaster

以因冰雪灾害造成森林资源损失较为严重的福建省长汀县为例,选取受灾乔木林为研究对象,结合实地踏查和典型抽样统计数据,评估森林乔木层C贮量损失并分析其主要影响因素.分析结果表明:冰雪灾害造成长汀县乔木林地受损面积达40178.87 hm2,占灾前面积的19.1%;损失蓄积95.69×104m3,占灾前蓄积的38.6%,折合成森林乔木层C贮量损失34.55×104t,占灾前C贮量的41.4%,受损最为严重的四都、红山、古城等6个乡(镇、场)都靠近武夷山脉南麓;同一区域相同的立地条件下,针叶树种比阔叶树种受灾严重,松组和杉组C贮量相对损失比均超过阔叶树组的3倍,其中松组C贮量损失23.02×104t,占总C贮量损失的66.6%,占灾前松组C贮量的65.0%;中龄林C贮量损失12.84×104t,占灾前中龄林C贮量的56.6%,相对损失比最大,近成过熟林次之,幼龄林最小;海拔越高,C贮量损失比例越大,海拔450 m以上区域C贮量损失达30.15×104t,占总C贮量损失的87.3%;迎风坡面和山脊西北侧的乔木林受灾相对严重,朝西、西北、北3个方向的C贮量损失20.11×104t,占总C贮量损失的58.2%;位于中上部坡位的乔木林受灾相对严重,且坡位越高,C贮量损失越大.

Changting county of Fujian province, where suffered heavy loss in forest resources brought by the ice-snow disaster, was taken as an example to evaluate and analyze the loss of carbon storage at arbor stratum and influencing factors. The result showed that the damaged area of arbor land was up to 40 178. 87 hm^2, which accounts for 19. 1% of pre-disaster area; the loss of reserves was up to 95.69 × 10^4 m^3, which accounts for 38.6% of pre-disaster reserves and equal to the loss of 34.55 × 10^4 t carbon storage at arbor stratum that accounts for 41.4% of pre-disaster carbon storage. The six seriously afflicted villages （including towns and wood fields） such as Sidu, Hongshan, Gucheng and so on, were mostly adjacent to the southern slope of Wuyi Mountain, where the loss of needle-leave tree exceeded that of broad-leave tree under same stand conditions. In these localities, the loss of Masson pine and Pine was 3 times higher than that of broad-leave trees. For Pine, the loss amounted to 23.02 ×10^4 t accounting for 66.6% of the whole of carbon storage, and 65.0% of pre-disaster carbon storage. For the medium-aged forest, the loss of carbon storage was up to 12.84 ×10^4 m^3 which was most serious and accounted for 56. 6% of pre-disaster carbon storage. With the increase of altitude, carbon storage loss percentage got higher, for instance, the loss of region above 450 m was 30. 15 ×10^4 t accounting for 87.3% of the whole of carbon storage. Relatively, the arbor tree located at upwind slopes and on the northwestern ridges was seriously affected. On the west, northwest and north slopes, the loss totaled 20. 11 ×10^4 t accounting for 58.2% of the whole.