Abstract
Drought and fire reduce productivity and increase tree mortality in tropical forests. Fires also produce pyrogenic carbon (PyC), which persists in situ for centuries to millennia, and represents a legacy of past fires, potentially improving soil fertility and water holding capacity and selecting for the survival and recruitment of certain tree life-history (or successional) strategies. We investigated whether PyC is correlated with physicochemical soil properties, wood density, aboveground carbon (AGC) dynamics and forest resistance to severe drought. To achieve our aim, we used an Amazon-wide, long-term plot network, in forests without known recent fires, integrating site-specific measures of forest dynamics, soil properties and a unique soil PyC concentration database. We found that forests with higher concentrations of soil PyC had both higher soil fertility and lower wood density. Soil PyC was not associated with AGC dynamics in non-drought years. However, during extreme drought events (10% driest years), forests with higher concentrations of soil PyC experienced lower reductions in AGC gains (woody growth and recruitment), with this drought-immunizing effect increasing with drought severity. Forests with a legacy of ancient fires are therefore more likely to continue to grow and recruit under increased drought severity. Forests with high soil PyC concentrations (third quartile) had 3.8% greater AGC gains under mean drought, but 33.7% greater under the most extreme drought than forests with low soil PyC concentrations (first quartile), offsetting losses of up to 0.68 Mg C ha–1yr–1 of AGC under extreme drought events. This suggests that ancient fires have legacy effects on current forest dynamics, by altering soil fertility and favoring tree species capable of continued growth and recruitment during droughts. Therefore, mature forest that experienced fires centuries or millennia ago may have greater resistance to current short-term droughts.
| Original language | English |
|---|---|
| Article number | 1024101 |
| Number of pages | 12 |
| Journal | Frontiers in Forests and Global Change |
| Volume | 6 |
| Issue number | 10224101 |
| DOIs | |
| Publication status | Published - 14 Feb 2023 |
Bibliographical note
Funding Information:This research was supported by the Coordination of Improvement of Personnel in Higher Education, Brazil (CAPES) grant to LV (No. 88881.128127/2016-01), CAPES-Science without Borders grant to TF (PVE 177/2012), and NERC (NE/N011570/1). The Amazon forest plots in the RAINFOR network analyzed here were established, identified and measured with support from many colleagues and grants mentioned elsewhere. This research was also supported by the NERC/FAPESP grants “BIO-RED” (NE/N012542/1 and 2012/51872-5), “ECOFOR” (NE/K016431/1 and 2012/51509-8), “ARBOLES” (NE/S011811/1), the Royal Society for the Global Challenge Award “FORAMA” (ICA/R1/180100), the National Council for Science and Technology Development of Brazil (CNPq) grants Cerrado/Amazonia Transition Long-Term Ecology Project (PELD/441244/2016-5 and PELD/441572/2020-0), the Rede Amazônia Sustentável Long-term Ecology Project (PELD-RAS; 441659/2016-0 and 441573/2020-7), the PPBio Phytogeography of Amazonia/Cerrado Transition Project (CNPq/PPBio/457602/2012-0), FATE Project (CNPq 458022/2013-6), FAPESP (2016/21043-8), CNPq/INCT 4067/2022-0, and productivity grants (PQ1) to BMJ, BM, LA (CNPq 314416/2020-0). This study was carried out as a collaborative effort of the ForestPlots.net meta-network, a cyber-initiative developed at the University of Leeds that unites contributing scientists and their permanent plot records from the world’s tropical forests. This manuscript is supported by ForestPlots.net Research Project #97, led by LV.
Publisher Copyright:
Copyright © 2023 Vedovato, Carvalho, Aragão, Bird, Phillips, Alvarez, Barlow, Bartholomew, Berenguer, Castro, Ferreira, França, Malhi, Marimon, Marimon Júnior, Monteagudo, Oliveira, Pereira, Pontes-Lopes, Quesada, Silva, Silva Espejo, Silveira and Feldpausch.