Reversals of Reforestation Across Latin America Limit Climate Mitigation Potential of Tropical Forests

GRAESSER, JORDAN; AIDE, T. MITCHELL; URIARTE, MARÍA; SCHWARTZ, NAOMI B.; GRAU, H. RICARDO

Frontiers in Forests and Global Change

Frontiers

Año: 2020 vol. 3 p. 1 - 10

Carbon sequestration through tropical reforestation and natural regeneration couldmake an important contribution to climate change mitigation, given that forest coverin many tropical regions increased during the early part of the 21st century. The sizeof this carbon sink will depend on the degree to which second-growth forests arepermanent and protected from re-clearing. Yet few studies have assessed permanenceof reforestation, especially not at a large spatial scale. Here, we analyzed a 14-yeartime series (2001?2014) of remotely sensed land-cover data, covering all tropicalLatin America and the Caribbean, to quantify the extent of second-growth forestpermanence. Our results show that in many cases, reforestation in Latin Americaand the Caribbean during the early 21st century reversed by 2014, limiting carbonsequestration. In fact, reversals of reforestation, in which some or all gains in forestcover in the early 2000s were subsequently lost, were ten times more common thansustained increases in forest cover. Had reversals of reforestation been avoided, forestscould have sequestered 0.58 Pg C, over four times more carbon than we estimate wassequestered after accounting for impermanence (0.14 Pg), representing a loss of 75%of carbon sequestration potential. Differences in the prevalence of reforestation reversalsacross countries suggest an important role for socio-economic, political, and ecologicalcontext, with political transitions and instability increasing the likelihood of reversals.These findings suggest that national commitments to reforestation may fall short oftheir carbon sequestration goals without provisions to ensure long-term permanenceof new forests.