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The occurrence and prevalence of pine wilt disease cause huge losses to Japan, China, and South Korea in East Asia, and have received concerns from many countries. By the methods of field observation and meteorological data analysis, this paper studied the characteristics of the occurrence and prevalence of pine wilt disease and their relations to the meteorological disaster events. In Japan, China and South Korea, the meteorological extreme events of persistent summer drought and strong typhoon could trigger the occurrence of pine wilt. In extremely dry and hot environment, pine trees often appeared energy metabolism imbalance and entire tree wilt. However, in the years with lower temperature and more rainfall, less or nearly no pine wilt event occurred. It was suggested that before the attack by pine wood nematode and its vectors, the vigor of the pines had already declined, and thus, pine wilt disease could be confined in the areas often hit by summer drought and strong typhoon events. In the areas with suitable natural environment characterized by less summer drought and strong typhoon events and no improperly enlarged pine planting, there would be little possibility of widespread occurrence of pine wilt disease.

Based on the bi-linearly interpolated meteorological reanalysis data from National Centers for Environmental Prediction, USA and by using the leaf area index data derived from the GIMMS NDVI to run the process-based Boreal Ecosystems Productivity Simulator (BEPS) model, this paper simulated and analyzed the spatiotemporal characteristics of the terrestrial ecosystem gross primary productivity (GPP) and net primary productivity (NPP) in East Asia in 2000-2005. Before regional simulating and calculating, the observation GPP data of different terrestrial ecosystem in 15 experimental stations of AsiaFlux network and the inventory measurements of NPP at 1300 sampling sites were applied to validate the BEPS GPP and NPP. The results showed that BEPS could well simulate the changes in GPP and NPP of different terrestrial ecosystems, with the R2 ranging from 0.86 to 0.99 and the root mean square error (RMSE) from 0.2 to 1.2 g C x m(-2) x d(-1). The simulated values by BEPS could explain 78% of the changes in annual NPP, and the RMSE was 118 g C x m(-2) x a(-1). In 2000-2005, the averaged total GPP and total NPP of the terrestrial ecosystems in East Asia were 21.7 and 10.5 Pg C x a(-1), respectively, and the GPP and NPP exhibited similar spatial and temporal variation patterns. During the six years, the total NPP of the terrestrial ecosystems varied from 10.2 to 10.7 Pg C x a(-1), with a coefficient of variation being 2. 2%. High NPP (above 1000 g C x m(-2) x a(-1)) occurred in the southeast island countries, while low NPP (below 30 g C x m(-2) x a(-1)) occurred in the desert area of Northwest China. The spatial patterns of NPP were mainly attributed to the differences in the climatic variables across East Asia. The NPP per capita also varied greatly among different countries, which was the highest (70217 kg C x a(-1)) in Mongolia, far higher than that (1921 kg C x a(-1)) in China, and the lowest (757 kg C x a(-1)) in India.