Forest fragmentation trends and modes in China: Implications for conservation and restoration

Forest fragmentation is a significant issue in China; however, a comprehensive understanding and assessment of the temporal trends and spatial modes of forest fragmentation remain lacking. For the first time, this study employs an object-based morphological image processing method to conduct multiscale spatiotemporal identification and analysis of China's forest landscape from 1985 to 2023. Observations reveal an overall improvement in the integrity of China's forest landscape from 1985 to 2023, with 79% of counties showing a positive trend in forest landscape integrity and 5 % experiencing forest fragmentation. The forest core area in China has almost tripled from 1985 to 2023, expanding from 0.57 to 1.53 million km2. Nevertheless, 32.04 % of forests in China remain within 100 m of a non-forest edge, significantly higher than the global average (similar to 20 %). From 1985 to 2023, out of the 0.33 million km(2) of newly planted forests, 29.5% became forest cores, while the remaining 70.5 % constituted forest edges. This underscores the need for government planning to focus not only on expanding forest areas but also on enhancing the integrity of forest landscapes, thereby creating more ecologically valuable forest ecosystems. Analysis indicates that 25 % of forest fragmentation in China is associated with agriculture (16 %) and urbanization (9 %), while the remaining portion is linked to local topography, climate, and other natural boundaries for forest distribution. Although natural boundaries play a predominant role in forest fragmentation, there is a growing trend of agricultural activities and urbanization encroaching upon the edges. It is recommended that government policies prioritize strategic planning for forest landscape integrity, considering both quantitative expansion and qualitative optimization, to ensure the sustainable development of China's forest ecosystems.