Land use and cover in subtropical East Asia and Southeast Asia from 1700 to 2018

Land-use/cover change (LUCC) has severely disturbed the terrestrial carbon balance in subtropical East Asia and Southeast Asia (SEASA). High-precision, long-term historical land cover (LC) data, and LC spatiotemporal patterns and transitions, exhibit high levels of uncertainty. This study constructed base and potential map containing 18 LC categories by integrating multisource high-resolution remote sensing datasets in 2014; then collected official reports, FAOSTAT, and long-term historical datasets, and used the correction coefficient method to obtain the area time series of forest, cropland, and urban at the provincial scale from 1700 to 2018; Finally, the fraction map of 18 LCs in SEASA at 1 km resolution during 1700–2018 was reconstructed based on a pixel level area calibration method, and the spatiotemporal patterns and transitions of LUCC were analyzed. Over the past 300 years, SEASA forest area decreased by 145.22 million ha, most rapidly from 1950 to 1980 (sevenfold that of the preceding 250 years). The loss of tropical forest, mainly in Indonesia, Myanmar, and Thailand, accounting for >80% of this decline. Subtropical forest areas increased significantly in China. Cropland and urban areas increased greatly, by 86.55 and 7.97 million ha, respectively, with the largest increases in China, Thailand, Myanmar, Japan, and Indonesia. Other natural land types closely related to human activity declined more, becoming cropland and urban areas, with greater variability. Conversion of forest to other LC types accounted for >70% of the total LC transition from 1700 to 2018. The main sources of cropland were forest (mainly in Thailand, central Myanmar, and southern Vietnam) and other nonforest natural land. Urban growth was mainly via encroachment on forest and other natural land. This study elucidates the spatiotemporal evolution of LUCC in SEASA from 1700 to 2018, and provides historical spatiotemporal data for large-scale bamboo forests, along with high-precision LUCC data for studying terrestrial ecosystem responses to climate change in the SEASA.