川西米亚罗地区岷江冷杉林过去223年森林净初级生产力重建

利用BIOME-BGC模型和树木年轮数据模拟1954~2008年川西米亚罗岷江冷杉林森林净初级生产力（NPP）动态，并构建了相应的NPP线性重建模型（方差解释量为44.8%），最终重建了该地区岷江冷杉林过去223年（1788~2010年）NPP的波动历史。在1788~2010年区间，岷江冷杉林NPP波动于498.66~563.65gC/m2/a之间，平均值和标准差分别为527.2gC/m2/a和12.45gC/m2/a。森林NPP主要上升时期有1788~1811年、1832~1844年、1890~1928年和1969~1993年，NPP主要的下降时期有1812~1831年、1845~1860年、1929~1968年和1994年至今。重建NPP序列与气象数据的相关和响应函数分析发现，夏季至秋季温度是限制森林生长的最为重要的气候要素，另外前一年秋季至初冬温度和春季至初夏的降雨对森林生长也有一定的控制性影响。树木年轮是一种指示森林NPP动态变化的可靠待用材料，可以检验和校正包括BIOME-BGC模型在内的各种生态系统过程模型。

TREE RING-BASED NET PRIMARY PRODUCTION OF Abies faxoniana FOREST OVER THE PAST 223 YEARS IN MIYALUO OF WESTERN SICHUAN,CHINA

Base on BIOME-BGC model and tree-ring data a modeling study was conducted to estimate the dynamic changes of the net primary productivity(NPP)of Abies faxoniana forest ecosystem in the Miyaluo Natural Reserve of western Sichuan of China(31.04°~31.92°N 102.58°~103.07°E). The sample site(31.63°N 102.96°E) of A. faxoniana in this study is located in the Jiabigou Ravine. In total we collected 88 cores from 88 living trees of S. squamata in a treeline site(4000m above sea level)at the northern slope side. A total of 76 increment cores were eventually crossdated and selected for chronology development. The resulted forest NPP reconstruction spanning 1788~2010(233 years) could explain 44.8% the variance(adjusted for degrees of freedom was 43.8%)contained in NPP data modeled by BIOME-BGC from the calibration period 1954~2008. The reconstruction indicated the annual NPP of Abies faxoniana forest in 1788~2010 fluctuated from 498.66gC/m2/a to 563.65gC/m2/a with the mean value and standard deviation of 527.2gC/m2/a and 12.45gC/m2/a respectively. The major decreasing episodes for forest NPP occurred during 1788~1811,1832~1844,1890~1928 and 1969~1993 whereas the distinct increasing episodes for forest NPP occurred during 1812~1831,1845~1860,1929~1968 and 1994~2010. The reconstructed NPP in this study revealed similarities at inter-decadal frequencies with tree-ring reconstructed temperatures from nearby regions as well as the δ18O value of ice cores and recorded glacier fluctuations in the surrounding high mountains which suggested the spatial fidelity of forest growth pattern deduced from our tree-ring data. Correlation and response analysis revealed that A. faxoniana forest NPP in this site was mostly governed by temperature from summer to autumn season(especially for months of July and September) and the temperature in prior autumn and winter played a secondary role to explain the climate related variance in forest NPP series. In contrast no consistent response pattern was found between forest NPP and precipitation only precipitation in summer to early summer suggests the existence of negative impact on forest growth. Tree-ring data act as reliable proxy to predict the ecosystem dynamic change over ecosystem and regional scales and could be used to validate the process-based ecosystem models and reconstruct the historical forest NPP during the past centuries.