Global patterns and drivers of post-fire vegetation productivity recovery

Abstract

Wildfires cause critical shifts in ecosystem functions, such as dramatic reductions in vegetation productivity. However, how fast vegetation regains its pre-fire productivity levels and the key influencing factors remain poorly understood on a global scale. Here we present the global estimates of post-fire vegetation productivity recovery from 2004 to 2021 using gross primary productivity observations and related proxies at a spatial resolution of 10 km, employing a random forest model to identify the key factors influencing recovery time. Roughly 87% of burned vegetation regained pre-fire productivity levels within 2 years, with evergreen needleleaf forests and savannas displaying the lengthiest recovery periods. During the recovery phase, post-fire climate conditions, such as soil moisture, vapour pressure deficit and air temperature, had nonlinear impacts on recovery time globally. These climatic factors exhibited a dominant role in regional recovery time in ~89% of the globally assessed area. As climate aridity decreased, the areas where recovery time was dominated by soil moisture and vapour pressure deficit decreased, while the influence of temperature increased. Soil-moisture-dominated regions witnessed reduced proportions of promoting vegetation recovery as aridity decreased, whereas vapour pressure deficit and air-temperature-dominated regions saw an increase in such proportions. Regions with strong human interventions were associated with accelerated vegetation recovery compared with similar ecosystems with smaller human interventions. These findings had important implications for global carbon-cycle assessments and fire-management strategies. More than 80% of vegetation burned globally regained its pre-fire level of productivity within 2 years, according to an assessment of post-fire vegetation productivity from 2004 to 2021.