Old-growth forest loss and secondary forest recovery across Amazonian countries

Abstract

There is growing recognition of the potential of large-scale restoration in the Amazon as a “nature-based solution” to climate change. However, our knowledge of forest loss and recovery beyond Brazil is limited, and carbon emissions and accumulation have not been estimated for the whole biome. Combining a 33-year land cover dataset with estimates of above-ground biomass and carbon sequestration rates, we evaluate forest loss and recovery across nine Amazonian countries and at a local scale. We also estimate the role of secondary forests in offsetting old-growth deforestation emissions and explore the temporal trends in forest loss and recovery. We find secondary forests across the biome to have offset just 9.7% of carbon emissions from old-growth deforestation, despite occupying 27.6% of deforested land. However, these numbers varied between countries ranging from 9.0% in Brazil to 23.8% in Guyana for carbon offsetting, and 24.8% in Brazil to 56.9% in Ecuador for forest area recovery. We reveal a strong, negative spatial relationship between old-growth forest loss and recovery by secondary forests, showing that regions with the greatest potential for large-scale restoration are also those that currently have the lowest recovery (e.g. Brazil dominates deforestation and emissions but has the lowest recovery). Our findings identify three important challenges for policy makers: (1) incentivising large-scale restoration in highly deforested regions, (2) protecting secondary forests without disadvantaging landowners who depend on farm-fallow systems, and (3) preventing further deforestation. Combatting all of these successfully is essential to ensuring that the Amazon biome achieves its potential in mitigating anthropogenic climate change.

Capítulo 25: Una Visión del Desarrollo Sostenible Panamazónico

“…These targets must consider regional differences regarding the level of conservation of remaining forests. Although the 80% target has been followed by all Amazonian countries so far (Smith et al 2021), some regions of the Basin are below this threshold. The eastern Amazon is an example of that, trespassing this threshold and impacting carbon and water fluxes with potential implications to other portions of the Amazon that are still preserved (Gatti et al 2021).…”

Linking land-use and land-cover transitions to their ecological impact in the Amazon

“…Between 2000 and 2005 at least 20% of tropical forests were selective logged ( 8 ), while other anthropogenic drivers and extreme droughts are increasing forest fires, with 54 million ha burned annually in the 1990s ( 9 ). Even deforested landscapes are changing; agricultural abandonment is a key driver of secondary forest regrowth, and now these forests account for at least half of all tropical forests globally ( 10 ), including 28% of deforested land in the Amazon ( 11 ). Other areas are undergoing agricultural intensification, with pastures being converted to croplands ( 12 , 13 ).…”

“… 15 and 16 ). We know, for example, that conversion of forests to pastures and degradation of primary forests are the main LULCTs in the Amazon ( 15 , 16 ), while secondary forest recovery is still very limited compared with deforestation ( 11 ). In addition, the value of human-modified tropical landscapes has been examined in detail for above-ground carbon storage ( 17 ), soil condition ( 18 ), vegetation structure ( 19 ), and biodiversity ( 20 ).…”

Amazonian forest degradation must be incorporated into the COP26 agenda

“…Addressing human-induced degradation requires going beyond identifying and quantifying the different types of disturbance. Above all, new strategies must be established to avoid and offset related emissions, including the sustainable use of forest resources, restoration of degraded old-growth forests 12 , and protection of secondary-growth forests 13,14 .…”