This short video, recorded by Professor Yadvinder Malhi in December 2017, shows the after-effects of fires that leaked into pristine Amazonian forests around Santarem in late 2015. The forests were affected by severe droughts, linked to a strong El Nino weather event, causing extensive fires to leak into mature tropical forests. The result was that over half the forest's trees were killed.
The effect of the El Nino drought was to dry the litter layer, making it highly flammable. The ensuing fires were were slow moving and only a few centimetres tall - they could effectively be stopped by kicking out a gap in the litter layer. But because these forests have no adaptation to fire, the result was the death of over half of the forest's trees. We are not really sure exactly why the trees are so vulerable - is it the tree vessels being damaged, or something to do with soil and root microbes? The resulting forest is now open, hot and dry, and even more vulnerable to a repeat fire that could tip the forest into a long-term degraded state. These overflight pictures show dramatic evidence of the extent of tree death two years on from these fires.
Last month, Professor Yadvider Malhi and colleagues convened a discussion meeting at the Royal Society in London into "The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications". The two-day event brought together an international and multidisciplinary community of scientists to describe and understand how the terrestrial tropics responded to the El Niño, and what this can tell us about future stability of the tropics and the global carbon cycle under climate change. Papers from the meeting will be collated into a future issue of Philosophical Transactions of the Royal Soceity B and will help us further our understanding about the future stability of these precious forests in an era of changing climate.