Drought-driven wildfire impacts on structure and dynamics in a wet Central Amazonian forest

Area of Science:

• Ecology
• Forest Science
• Climate Change Impacts

Background:

• Amazonian forests face increasing degradation from climate change and human activity.
• Fire's impact on forest dynamics in wetter Amazonian regions is understudied, despite susceptibility during extreme droughts.

Purpose of the Study:

• To investigate the effects of wildfire on forest dynamics in the Central Amazon.
• To assess how fire intensity and tree traits influence growth and mortality post-wildfire.

Main Methods:

• Established burned and unburned plots after a 2015 wildfire in the Purus-Madeira region.
• Monitored tree demographics (density, biomass, growth, mortality) for three years.
• Analyzed the influence of fire intensity (char height) and tree traits (size, wood density).

Main Results:

• Burned forests lost 27.3% of stem density and 12.8% of biomass, primarily small and medium trees.
• Mortality drove initial losses, followed by reduced recruitment.
• Fire increased growth in larger trees with lower wood density; higher char height temporarily increased mortality.

Conclusions:

• Fire impacts in wetter Amazonian forests are less severe than in drier regions.
• Larger trees and higher wood density offer some fire resistance, but intense fires linked to climate change remain a significant threat.