Characterizing the spatial patterns of on- and off-year Moso bamboo forests with multisource data in Southeast China

Moso bamboo forests (MBFs) exhibit unique phenological phenomena, such as on-/off-years, which play an important role in regulating the sustainable management of MBF ecosystems. With human disturbance, on- and off-year effects occur at both spatial and temporal scales. Quantifying the spatial pattern of MBF performance remains a challenge because of physiological and ecological complexity, regional policy differences and human management intensity. In this paper, three zones (Anji, Guangde and Yixing) with similar administrative areas were selected for study. An on-/off-year MBF map was constructed by Sentinel-2 time series data and the multitemporal bamboo index. The spatial distribution patterns of the on-/off-year MBFs were analyzed from different perspectives, such as administrative zones and physical conditions. A new Moso bamboo on-/off-year differentiation index (MODI) was proposed, and MODI spatial pattern maps for different administrative zones were completed and comparatively analyzed. The results showed that (1) the total administrative area of each study zone was nearly 2000 km2, but the MBF distribution areas were quite different, and the MBF spatial areas in Anji, Guangde and Yixing were 637.6 km2, 334.5 km2 and 112.0 km2, respectively. (2) The MBFs were mainly distributed in mountainous areas, especially at elevations ranging from 100 to 400 m and slopes ranging from 5 to 35 degrees. (3) On- and off-year MBFs occurred in different provinces; generally, the area of the off-year MBFs was larger than that of the on-year MBFs in each zone in 2019. (4) The newly proposed MODI can effectively detect spatial distribution differences between the on- and off-year MBFs in a region, providing valuable information for government decision-making and bamboo forest management.