The Amazon rainforest is a vital part of our planet, known for its rich biodiversity and important role in maintaining environmental balance. However, the frequency and severity of forest fires in the Amazon have increased in recent years due to climate change and human activities. These fires release large amounts of carbon dioxide and disrupt the forest’s ability to function as a carbon sink, affecting its resilience to climate change. Understanding how the forest recovers after these fires is essential to preserving its ecological health.

A pioneering study led by Prof. Jin Wu’s team at the School of Biological Sciences, HKU has redefined how scientists evaluate forest recovery after wildfires in the Amazon, offering transformative insights for global conservation strategies. The research team studied nearly 3,000 fire events in the eastern Amazon from 2001 to 2020, using various remote sensing tools and machine learning techniques. They were able to classify the burned areas into zones of natural recovery and those affected by human activity, with an accuracy of 87.9%.

The study found that in areas where human influence is minimal, the forest’s canopy structure—such as its height, coverage, and plant density—can almost return to pre-fire conditions within 20 years. Notably, the plant area index, which measures how vegetation fills the vertical space, showed significant recovery. On the other hand, areas impacted by human activities continue to degrade and lose their ability to naturally regenerate.

This research not only addresses the challenges of distinguishing between natural recovery and human disturbance but also stresses the importance of managing ecological recovery after fires. It provides a new perspective for accurately assessing ecological resilience in protected areas. The findings highlight the need to establish a more precise post-fire monitoring system, incorporate canopy structure indicators into evaluation standards, and enhance protection efforts for areas with high recovery potential. Furthermore, the study points out that weakened environmental policies have allowed illegal activities that worsen ecological damage in protected areas after fires. The findings of this study provide crucial insights for conservation efforts in the Amazon rainforest and offer valuable guidance for understanding forest recovery in the context of global climate change.

The research, titled “Improved Assessment of Post-Fire Recovery Trajectory of Forests in Amazon’s Protected Areas”, was recently published in the leading journal of the field, Remote Sensing of Environment. The paper is led by Miss. Qianhan Wu, PhD student of Prof. Jin Wu’s lab, with Prof. Jonathan Wang from the University of Utah, Prof. Eduardo Maeda from the University of Helsinki, Prof. Yanjun Sun from the Chinese Academy of Sciences, Prof. Alfredo Huete from the University of Technology Sydney as key collaborators, and Prof. Alice Hughes from the University of Hong Kong. This research was supported by the National Natural Science Foundation of China, the Research Grants Council of Hong Kong, State Key Lab of Agrobiotechnology, and the Seed Fund of the University of Hong Kong.

For more details, the full article is available at: https://doi.org/10.1016/j.rse.2025.114802.