Trends in vegetation activity and their climatic correlates: China 1982 to 1998

We combined a satellite-derived Leaf Area Index (LAI) dataset and a gridded climate dataset to analyse trends in vegetation activity and their correlation with climate variability in China between 1982 and 1998. Vegetation activity over the growing season increased 11.03% in China during the 17-year period, which is broadly consistent with the greening trend in the northern high latitudes in Eurasia and North America shown in previous studies. Approximately 99 X 10(6) ha of croplands and 35 x 10(6) ha of forest exhibited significant upward trends in growing season LAI, and accounted for 53% and 19% of the total vegetated area with greening trends, respectively. Temperature was the leading climatic factor controlling greening patterns. However, trends in agricultural practices, such as increased use of high-yield crops and application of chemical fertilizers, along with land-use changes such as afforestation and reforestation probably made a greater contribution to the greening trend than temperature. Increased vegetation activity in forests suggests an increasing carbon stock in forest biomass in China, which supports previous studies based on satellite sensor data and forest inventory data.