Natural Forests Have Longer Drought Recovery Times than Planted Forests across China

Planted forests (PF) and Natural forests (NF) are essential carbon sinks and biodiversity reservoirs. The increasing severity of drought events has intensified stress on both. However, the extent to which PF and NF differ in their drought recovery times remains unclear. To address this, we assessed the differences in the drought recovery time between PF and NF based on the Kernel Normalized Difference Vegetation Index (kNDVI) and the Standardized Precipitation Evapotranspiration Index (SPEI). The results showed that NF exhibited a significantly longer drought recovery time (NF_RT: 3.14 ± 1.97 months) than PF (PF_RT: 2.90 ± 2.05 months). The environmental factors, including recovery-period climate variables, drought characteristics, and soil fertility, were important drivers of both PF_RT and NF_RT, with the average precipitation during the recovery period showing the greatest difference in contribution between PF_RT and NF_RT. During the recovery period, PF areas experienced higher temperature and precipitation, resulting in warmer and wetter conditions that were more conducive to shortening drought recovery time. The effects of vegetation factors on PF_RT and NF_RT exhibited nonlinear relationships, and the local responses of key variables such as gross primary productivity and water-use efficiency differed, suggesting that optimizing the structure and function of plantations and natural forests could enhance their adaptation to drought events. Our results emphasize the difference in drought recovery time between PF and NF, highlighting the distinct ecological strategies and adaptation mechanisms employed by the two forest types under drought stress.