Identification of potential forest thinning locations to mitigate water deficits in drylands

Abstract

Appropriate forest thinning measures can mitigate the conflicting relationship between past excessive afforestation and current increasing regional water deficiency in dryland ecosystems. However, since blind intervention in forest landscapes may incur additional economic costs and cause the loss of ecosystem services, forest thinning in drylands mostly exists in scientific discussions and is seldom implemented in reality. In this study, we propose an advanced technical route to predict the spatial arrangement of potential forest thinning locations under different policy scenarios. Taking Shanxi Province in China as a case study, we simulated eight policy scenarios for different stakeholders to assess the benefits and costs after forest thinning in the future. The results show that a water deficit of 533 million m3 exists in Shanxi Province that could potentially be mitigated by means of forest thinning. Under different policy scenarios, the thinned area ranged from 1142.91 to 1195.47 km2, which would result in an additional soil loss of 1.77–3.02 million m3/year and a loss of carbon sequestration of 3.15–3.24 million t/year. Considering both soil conservation and food security scenarios can help minimize the direct costs and loss of forest carbon sequestration capacity and maintain a sustainable landscape pattern. The method can be used as a decision support tool to identify the potential locations of forest thinning and resulting consequences under water scarcity conditions in drylands and to support stakeholders in making scientific adaptive forest landscape optimization decisions.