Abstract

Increasing numbers of wildfires have resulted in severe post-fire effects on the environment. Understanding post-fire recovery is important for post-fire management. However, an in-depth evaluation of the spatiotemporal dynamics of burn degree is rarely reported around the world, which is not conducive to accurate post-fire management. This study aimed to assess the changes in the degree of burn during the early post-burn period (June 15, 2018–July 27, 2019) to influence the post-fire management. The dNBR (difference Normalized Burn Ratio)-based burn index model was used to estimate the changes in burn degree. The results revealed that the burn degree had decreased from severe burns on June 15, 2018 to moderate burns on July 27, 2019, and the post-fire recovery period takes a long time. The rate of decrease in burn degree in the latter period (January 25, 2019–July 27, 2019) was much higher than that in the earlier period (June 15, 2018–January 25, 2019). The survival and growth of Dicranopteris pedata primarily led to a marked reduction in the burn degree in the latter period. The burned areas would have a markedly negative effect on the environment in the earlier period (within approximately half a year after the fire). Moreover, the lower severely burned sites can continue to degenerate and translated into higher ones during the earlier period owing to poor environmental conditions for the growth of vegetation and the influence of seasonal changes. These findings emphasize the importance of the timely strengthening of the earlier post-fire recovery in our area. In addition, the estimation of the time-space changes of the burn degree using remote sensing data helps local authorities to know which burned areas should be preferentially selected for post-fire recovery (i.e., higher burned areas). In brief, our study enriches the knowledge of the early post-fire recovery in southeast China and provides an example for the study of the post-fire recovery in other regions of the world.