Strong and Rapid Postfire Recovery of Vegetation Productivity in Australia

Fires disrupt ecosystems, release carbon, and reduce carbon uptake, which increases atmospheric CO₂ concentration, warms the atmosphere, and fosters more frequent and intense fires. Quantifying postfire recovery is crucial for understanding the adaptability and resilience of ecosystems to fire disturbances. Observations from satellite-derived active fire (~1-km) and Gross Primary Productivity (GPP) products reveal that Australia experiences extensive fires annually, reducing vegetation productivity. Here we analyze the post-fire GPP recovery trajectories of 1.7 × 10⁶ fire-affected pixels (or 1.5 × 10⁶ km²) in Australia between 2011 and 2019, of which 1.3 × 10⁶ pixels (1.2 × 10⁶ km²) experienced a single fire (single-fire pixels), and 0.4 × 10⁶ pixels (0.3 × 10⁶ km²) experienced two or more fires (multiple-fire pixels). We found that Australia's postfire GPP recovery was strong and rapid. 88% of single-fire pixels recovered to 135% of the prefire level in an average of 2.3 years, whereas 86% of multiple-fire pixels recovered to 115% of the prefire level in an average of 1.2 years. NonForest ecosystems (e.g., grasslands, shrublands, and savannas) exhibited a higher postfire recovery magnitude (138% for single-fire pixels and 115% for multiple-fire pixels) compared to Forest (110% for single-fire pixels and 108% for multiple-fire pixels). This rapid and robust postfire GPP recovery is significantly influenced by postfire precipitation, fire (i.e., fire frequency, intensity) and fire severity (damage, impacts; a metric of resistance of terrestrial ecosystems to fire). Specifically, higher fire severity and higher postfire precipitation have a positive impact on postfire recovery, whereas increased fire frequency has a negative impact. Furthermore, fire dynamics have a smaller role in the long-term interannual continental GPP changes than climate or land-use changes, as strong and rapid GPP recovery offsets the short-term fire-induced GPP losses.