Tree cover increase mitigation strategy: implications of the replacement approach in carbon storage of a subtropical ecosystem

MANRIQUE, SILVINA MAGDALENA; FRANCO, JUDITH

MITIGATION AND ADAPTATION STRATEGIES FOR GLOBAL CHANGE

Springer

Año: 2020

1381-2386

Worldwide tree cover increase (TCI) is one the most important climate change mitigationstrategies, given the role of the ecosystems as carbon (C) reservoirs. Reforestation couldbe key to achieving TCI. However, there is still a knowledge gap about its real mitigationeffects when it is applied through its replacement approach (REP-app). We evaluate theREP-app effects (replace native forest cover?NFC?by forestry plantation cover?FPC)on magnitude and direction of ecosystem C stock changes. By means of a field study, wequantified the C stock through a space-for-time substitution method, using eight pairedsites (NFC/FPC) in a northern Argentinian subtropical forest (SAY). We studied C insaplings, lianas, above and belowground biomass, dead organic biomass, and soil.Through a metaanalysis, we evaluated the reliableness within the response of C sequestration (gain or loss) in international study cases and, therefore, the robustness ofoutcomes analyzing some main moderator variables that may influence the result. Asignificant effect of C loss was revealed by both, the field study (− 50%) and themetaanalysis (− 20.4%), and this response was consistent through stands of ages andspecies different. SAY sequestered 285 MgC ha−1. Only 35-year-old Eucalyptus standreached similar values, but they are reservoirs of doubtful permanence with functionalattributes that could affect long-term ecosystem functioning. Given that the TCI strategyseek to achieve interconnected efforts in relation to climate, biodiversity, and sustainabledevelopment, the REP-app must not be considered a mitigation strategy in subtropicalecosystems. Global programs promoting TCI must be redirected urgently.