福州市森林碳储量定量估算及其对土地利用变化的响应

基于RS与GIS技术,以遥感影像数据、土地利用数据、森林资源二类调查数据为主要数据源,采用逐步回归法建立森林蓄积量定量估测模型。根据"蓄积量-生物量-碳储量"推算方法,对福州市森林植被碳储量和碳密度进行估算。建立福州市土地利用转移矩阵,分析2000—2010年土地利用变化影响下的福州市森林碳储量变化特征。结果表明:(1)根据不同的森林类型,即常绿阔叶林、常绿针叶林、针阔混交林分别建立的多元线性回归模型修正决定系数分别为0.599、0.679、0.694,通过模型适用性检验和精度验证。(2)2000年、2010年福州市森林植被碳储量总量分别为12.499Tg、12.642Tg,植被碳密度分别为18.694、18.708 t/hm~2,森林植被碳储量增加了1.430×10~5t。(3)福州市闽清县、永泰县、闽侯县的森林植被碳密度常年保持较高水平,并呈现出增长趋势;罗源县、长乐市、连江县森林植被碳密度较低,并呈现下降趋势。(4)2000—2010年,灌木和耕地是主要土地利用类型转出者,森林和建设用地是主要土地利用类型转入者。森林主要由灌木和耕地转化,主要向建设用地、耕地进行转化。由于土地利用变化,10年间福州市总碳储量减少了1.711×10~4t,其中土壤碳储量减少2.230×10~3t,植被碳储量减少1.489×10~4t。

The quantitative estimation of forest carbon storage and its response to land use change in Fuzhou, China

In this study, remote sensing (RS) images, land-use data, and forest resource inventory data were used to build a quantitative estimation model of forest volume via the stepwise regression method. The carbon storage and carbon density of forest vegetation in Fuzhou from 2000 to 2010 were analyzed using the Biomass Expansion Factor (BEF) method to correlate forest volume with volume, biomass and carbon storage. A land use transition matrix was created, and used to study the variation of forest carbon storage in response to land use change in Fuzhou. The results showed that:(1) the results of quantitative estimation models of forest volume which were build according to different type of forest (Evergreen broad-leaved forest, Evergreen coniferous forest, Mixed broadleaf-conifer forest) turned out the effects with the adjusted R² being 0.599, 0.679, 0.694 respectively. All quantitative estimation models of forest volume passed the applicability and accuracy test. The calculated total forest volume in Fuzhou was 2.097×10⁷ m³ in 2000 and 2.594×10⁷ m³ in 2010, revealing an increase in volume over the course of a decade. Of all the geographical subdivisions of Fuzhou, Yongtai County maintained the greatest forest volume throughout the decade, while Changle County contained the lowest forest volume. (2) Total carbon storage by forest vegetation in Fuzhou city was 12.499 Tg in 2000 and 12.642 Tg in 2010. Thus, in ten years, forest vegetation carbon storage increased by 1.430×10⁵ t. The vegetation carbon densities in 2000 and 2010 were 18.694 t/hm² and 18.708 t/hm², respectively. (3) The carbon density of forest vegetation in Minqing County, Yongtai County, and Minhou County, which are located in western Fuzhou, remained high during this ten year period, and was observed to increase overall. In contrast, Luoyuan County, Changle County, and Lianjiang County, which are located in eastern Fuzhou, experienced declines in the carbon density of forest vegetation, as a result of increasing socio-economic and anthropogenic activity. (4) In these areas, the forest was mostly converted to shrub and crop land between 2000 and 2010. As a result of this change in land use, forest carbon storage in Fuzhou declined by 1.711×10⁴ t overall. In addition, soil carbon storage and plant carbon storage decreased by 2.230×10³ t and 1.489×10⁴ t, respectively.