Response Of Net Primary Productivity Of Larix Olgensis Forest To Climate Change In Northeast China Response Of Net Primary Productivity Of Larix Olgensis Forest To ClimateChange In Northeast China

It is of great significance to study the interaction between forest ecosystems and climate change under the background of global climate warming. Due to its special geographical location and complex climate conditions, northeast China plays an important irreplaceable role in the study of the impact of global climate warming on forest ecosystems. Based on the BIOME-BGC model, a modeling study was conducted to simulate the dynamic changes of net primary productivity (NPP) of Larix olgensis forest in northeast China. The Morris and EFAST sensitivity methods were used to screen the sensitive parameters that had strong influence on NPP of Larix olgensis forest. Then, we analyzed the temporal climate variation of northeast China using meteorological data during the period of 1980 to 2014, and verified the simulating ability of the BIOME-BGC model using the field-measured productivity data. The response of NPP to natural climate change and different climate change situations were explored. We also analyzed the dynamics of NPP of Larix olgensis forest in northeast China under the SRES A2 and B2 scenarios during the period of 1980-2014. The results were shown as follows:(1) The Morris sensitivity method provided a reliable parameter sensitivity analysis result under the condition of a relatively small sample size. The EFAST sensitivity method could quantitatively measure the impact of simulation result of a single parameter as well as the interaction between the parameters in BIOME-BGC model. The influential sensitive parameters for Larix olgensis forest NPP are new stem carbon to new leaf carbon allocation and leaf carbon to nitrogen ratio, in addition, the effect of their interaction was significantly greater than the other parameters’interaction effect.(2) In the past 35 years, air temperature showed arising trend in northeast China. Apart from a slight increase trend, the annual precipitation had no obvious change. During the period of 1980-1997, the annual average temperature in the northeast China was 4.43 ℃ with the standard deviation of 1.87 ℃, and the annual average precipitation was 544.62 mm with the standard deviation of 144.21 mm. During the period of 1998-2014, the annual average temperature in the northeast China was 4.71 ℃ with the standard deviation of 2.86 ℃, and the annual average precipitation was 531.21 mm with the standard deviation of 191.89 mm.(3) Based on the BIOME-BGC model simulation results, the mean NPP of Larix olgensis forest in the northeast China was 725.80 g/(m2a), fluctuating between 581.46 and 867.65 g/(m2a) during 1980-2014. The linear regression analysis showed that the NPP of Larix olgensis forest in the northeast China had no obvious change trend in general.(4) There was a significant negative correlation between the NPP of Larix olgensis forest and annual air temperature, and a positive correlation with precipitation. Under the condition of natural climate change, the mean NPP of Larix olgensis forest in the northeast China will decrease and the variable rate will increase, with increasing variable rate of the temperature and precipitation. Similarly, under different climate change scenarios, the variable rate of NPP of Larix olgensis forest in the northeast China will increase with increasing variable rate of the temperature and precipitation.(5) Under the SRES A2 and B2 emissions scenarios, the mean NPP of Larix olgensis forest in the northeast China will decrease and the fluctuation range will increase gradually.