Vegetation restoration in South China’s karst region under geological background constraint: Forest or non-forest

Abstract

Over the past two decades, the karst region in southern China has emerged as a critical area for ecological conservation and restoration, attracting global attention for its efforts in ‘greening.’ However, particular areas face challenges transitioning into forests due to the carbonate bedrock constraint, which likely undermines sustainability of greening efforts in karst regions. This study overviews the significant achievements in vegetation restoration in the karst region of southwest China, emphasizing the potential of short-term ecological restoration in effectively sequestering carbon, a valuable approach to achieving carbon neutrality in the region. However, combating rocky desertification remains difficult due to geological limitations that hinder large-scale afforestation. Additionally, variations in soil and rock composition impact the success and quality of vegetation restoration, leading to some areas failing to establish forests. Therefore, establishing the goals for rocky desertification control in different regions (enhancement, degradation, or reduction) should be based on current conditions and the evolutionary characteristics of rocky desertification. To facilitate precise afforestation and grass planting in the karst region, factors such as climate, rock conditions, and human-environment relationships should be considered in regional divisions, including natural restoration zones, artificial afforestation zones, grass planting zones, and protected zones.

A Social‐Ecological Framework to Enhance Sustainable Reforestation Under Geological Constraints

“…It should be highlighted that not all karst regions are suited for afforestation, because prolonged human impact has created alternative stable states with eroded/shallow soils that cannot be reverted into forests (Pausas & Bond, 2020;Yue et al, 2023). This scientific foundation not only contributes to China's concept of eco-civilization, but also informs the implementation of major projects for the protection and restoration of national key ecosystems (2021)(2022)(2023)(2024)(2025)(2026)(2027)(2028)(2029)(2030)(2031)(2032)(2033)(2034)(2035).…”

“…Evolving from intense human disturbances to large‐scale afforestation and natural recovery, South China Karst has emerged as a global leader in vegetation greening. The area of rocky desertification in eight provinces of Southern China has consistently decreased from 129,600 km 2 in 2005 to 67,400 km 2 in 2021 (Yue et al., 2023). Over the past two decades, South China Karst has emerged as a focal point for global vegetation growth, contributing 5% to the world's carbon sink, while accounting for only 0.36% of the global land area (Brandt et al., 2018; Chen et al., 2019).…”

“…Additionally, the area exhibits a scarcity of soil mass, characterized by thin soil layers with low insoluble acid content, leading to a deficiency of mineral nutrients in the soil‐vegetation ecosystem (Zhang & Wang, 2011). Consequently, the effectiveness of vegetation restoration in the karst area exhibits significant spatial heterogeneity, with some regions encountering challenges in achieving successful forestation (Yue et al., 2023).…”

“…Subsequently, reforestation efforts have failed in certain areas, particularly in limestone regions with minimal soil and in dolomite areas with undeveloped bedrock crevices. Therefore, uncertainties persist in the feasibility of reforestation in some areas of South China Karst following human disturbances (Yue et al., 2023).…”

“…Furthermore, the carbonate bedrock likely undermines the sustainability of forestation efforts in the karst regions. Some areas face challenges transitioning into forest ecosystems after prolonged human disturbances, in particular deforestation (Yue et al, 2023), and some areas may have a naturally low tree cover and do not require forestation (Parr et al, 2024). However, although being a hotspot of global greening, there has been little attention on the sustainability of reforestation under geological constraints.…”