Bastin et al.’s estimate (Reports, 5 July 2019, p. 76) that tree planting for climate change mitigation could sequester 205 gigatonnes of carbon is approximately five times too large. Their analysis inflated soil organic carbon gains, failed to safeguard against warming from trees at high latitudes and elevations, and considered afforestation of savannas, grasslands, and shrublands to be restoration.
We develop an analytic framework for the analysis of robustness in social-ecological systems (SESs) over time. We argue that social robustness is affected by the disturbances that communities face and the way they respond to them. Using Ostrom's ontological framework for SESs, we classify the major factors influencing the disturbances and responses faced by five Indiana intentional communities over a 15-year time frame. Our empirical results indicate that operational and collective-choice rules, leadership and entrepreneurship, monitoring and sanctioning, economic values, number of users, and norms/social capital are key variables that need to be at the core of future theoretical work on robustness of self-organized systems.
Many countries have adopted large-scale tree-planting programs as a climate mitigation strategy and to support local livelihoods. We evaluate a series of large-scale tree planting 23 programs using data collected from historical Landsat imagery in the state of Himachal Pradesh 24 in Northern India. Using this panel dataset, we use an event study design to estimate the 25 socioeconomic and biophysical impacts over decades of these programs. We find that tree plantings have not, on average, increased the proportion of forest canopy cover, and have modestly shifted forest composition away from the broadleaf varieties valued by local people.Further cross-sectional analysis, from a household livelihood survey, shows that tree planting supports little direct use by local people. We conclude that decades of expensive tree planting programs in this region have not proved effective. This result shows that large-scale tree planting may sometimes fail to achieve its climate mitigation and livelihood goals.3
MainMany countries have begun adopting large-scale tree-planting programs based on the potential of forests to absorb carbon and support local livelihoods 1-3 . As of 2015, the extent of 35 global tree cover from planted forests is estimated at 280 million hectares, and 12 million 36 hectares lie within India 4 . Despite the broad appeal of planting trees, some researchers and practitioners have raised concerns about potential negative impacts of large-scale tree-planting programs on vulnerable people and diverse ecosystems [5][6][7] . Restoration ecologists have cautioned 39 that tree planting should not be equated with forest restoration, but instead countries should 40 consider diverse restoration strategies in diverse ecosystems 7 . However, forest restoration commitments made under international agreements like the Bonn Challenge and UNFCCC Paris Accords demand nationally-coordinated efforts to achieve ambitious restoration targets at immense scale 8 . As a result, much of the current nationally-pledged restoration area is set aside 44 for large-scale tree planting 2,9 . For example, the Indian National Determined Contributions 45 (NDC) from the Paris Accords commits "To create an additional carbon sink of 2.5 to 3 billion 46 tonnes of CO2 equivalent through additional forest and tree cover by 2030" 10 . Understanding the 47
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.