Mapping the future afforestation distribution of China constrained by a national afforestation plan and climate change

Abstract

Afforestation has been considered a critical nature-based solution to mitigate global warming. China has announced an ambitious afforestation plan covering an area of 73.78×104 km2 for the period 2020–2050. However, it is unclear which areas will be suitable for afforestation under future climate change. Here, we carried out a finer-resolution (25×25 km) dynamical downscaling of climate change for China using the Weather Research and Forecast (WRF) model nested with the bias-corrected MPI-ESM1-2-HR model. Then, using the Holdridge life zone model forced by the WRF model output, we mapped the climatological suitability for forests in China. The results showed that the potential forestation domain (PFD) at present (1995–2014) approximated 500.75×104 km2, and it would increase by about 3.49 % to 518.25×104 km2 in the period 2041–2060 under the Shared Socioeconomic Pathway (SSP) scenario (SSP2-4.5). Considering the expansion of the future PFD due to climate change, the afforestation area for each province was allocated to grid cells following the climatological suitability for forests. The new afforestation grid cells would be located around and to the east of the Hu Line (a geographical division stretching from Heihe to Tengchong). Due to afforestation, the land cover would be modified. The conversion from grasslands to deciduous broadleaf forests in northern China took up the most area, accounting for 40 % of the new afforestation area. The grid-cell-resolved afforestation dataset was consistent with the provincial afforestation plan and the future climatological forest suitability. The dataset would be valuable for investigating the impacts of future afforestation on various aspects, including the carbon budget, ecosystem services, water resources, and surface hydroclimate regime.