长白山阔叶红松林生态系统碳动态及其对气候变化的响应

应用基于干物质生产理论的过程模型（Sim-CYCLE）估算了1982—2003年间长白山阔叶红松林生态系统总第一生产力（GPP）、净第一生产力（NPP）、净生态系统生产力（NEP）及其季节动态变化以及碳储量（WE）、植物碳储量（WP）和土壤碳储量（WS），并分析了这些指标在当前气候情景和碳平衡情况时的差异及其对未来气候变化情景的响应.结果表明：在当前气候情景下, 长白山阔叶红松林GPP、NPP和NEP分别为14.9、8.7和2.7 Mg C·hm^-2·a^-1，三者分别比实测值减少2.8 Mg C·hm^-2·a^-1、增加1.4 Mg C·hm^-2·a^-1和增加0.2 Mg C·hm^-2·a^-1;长白山阔叶红松林6—8月的NEP占全年总量的90%以上，其中，7月最高（1.23 Mg C·hm^-2·month^-1）;研究区WE、WP和WS分别为550.8、183.8和367.0Mg C·hm^-2，其与实测值均具有较高的一致性.从当前气候情景下到达碳平衡前，长白山阔叶红松林碳储量均有不同程度的增加，GPP和NPP分别为17.7和7.3 Mg C·hm^-2·a^-1，表明研究区碳“汇”的作用随着碳储量的增加逐渐减弱;温度增加2 ℃时，不利于长白山阔叶红松林GPP、NPP和NEP的增长，CO²浓度倍增则可有利地促进三者的增长，CO²浓度倍增、温度增加2 ℃对GPP、NPP和NEP增幅的影响与单纯CO₂浓度倍增的影响相似，气候变化情景对长白山阔叶红松林碳储量的影响规律与对生产力幅度的影响相同，这可能是生态系统生产力影响碳积累所致.

Carbon dynamics of broad-leaved Korean pine forest ecosystem in Changbai Mountains and its responses to climate change.

By using process model Sim-CYCLE based on dry matter production theory, this pa per estimated the gross primary productivity (GPP), net primary productivity (NP P), net ecosystem productivity (NEP), ecosystem carbon storage (WE), total plant carbon storage (WP), and total soil carbon storage (WS) of broad-leave d Korean pine forest ecosystem in Changbai Mountains from 1982 to 2003, and anal yzed the variations of these indices under present climate condition and carbon equilibrium state as well as the responses of these indices to climate change sc enarios in the future. Under present climate condition, the estimated GPP, NPP, and NEP were 149, 87, and 27 Mg C·hm-2·a-1, being 28 Mg C ·hm-2·a-1 less and 14 and 02 Mg C·hm-2·a-1 highe r than the measured values, respectively. The NEP in June〖KG-*3〗-〖KG-*7〗August occupied more than 90% of the annual NEP, and the maximum monthly NEP appeared in July (123 Mg C·hm-2·month-1). The estimated WE, WP, and WS were 5508, 183 8, and 3670 Mg C·hm-2, respectively, very close to the me asured values. From present climate condition to carbon equilibrium state, the e stimated carbon storages of the forest ecosystem increased to some extent, with the GPP and NPP being 177 and 73 Mg C·hm-2·a-1, respectively, suggesting that the role of the forest ecosystem as a carbon “sink” declined g radually with the increase of carbon storage. A 2 ℃-increment of air temperat ure did not benefit the increase of GPP, NPP and NEP, while doubling CO2 conce ntration was in adverse. The effects of the combination of doubling CO2 concen tration and 2 ℃-increment of air temperature on the GPP, NPP, and NEP were si milar to those of doubling CO2 concentration. The climate change scenario in t he future had the same effects both on the carbon storage and on the productivit y of the forest ecosystem, which was mainly correlated to the effects of primary productivity on the carbon storage.