Viewpoint Pitfalls of Tree Planting Show Why We Need People-Centered Natural Climate Solutions Downloaded from https://academic.oup.com/bioscience/advance-article/doi/10.1093/biosci/biaa094/5903754 by Sveriges Lantbruksuniversitet user on 16 September 2020 FORREST FLEISCHMAN, SHISHIR BASANT, ASHWINI CHHATRE, ERIC A. COLEMAN, HARRY W. FISCHER, DIVYA GUPTA, BURAK GÜNERALP, PRAKASH KASHWAN, DIL KHATRI, ROBERT MUSCARELLA, JENNIFER S. POWERS, VIJAY RAMPRASAD, PUSHPENDRA RANA, CLAUDIA RODRIGUEZ SOLORZANO, AND JOSEPH W. VELDMAN cientists, corporations, mystics, ecologically effective and socially just on forests and trees, scientists and Sand movie stars have convinced strategies to improve climate mitiga- policymakers miss the opportunity policymakers around the world that tion efforts. to conserve and restore the wide a massive campaign to plant trees diversity of Earth’s ecosystems that should be an essential element of Ecosystems, not tree planting contribute to climate change mitiga- global climate policy. Public dialogue campaigns, capture and store tion and adaptation. has emphasized potential benefits carbon of tree planting while downplaying In terrestrial ecosystems, plants cap- Preventing ecosystem destruction pitfalls and limitations that are well ture carbon from the atmosphere, is the most cost-effective natural established by social and ecological which is stored in biomass and soils. climate solution research. We argue that if natural cli- Through processes including micro- Because ecosystems are crucial mate solutions are to succeed while bial decomposition, herbivory, and to carbon sequestration, avoiding economies decarbonize (Griscom fire, carbon is released back to the deforestation, improving forest man- et al. 2017), policymakers must recog- atmosphere. Because most ecosys- agement, and protecting grasslands, nize and avoid the expense, risk, and tems have the potential to capture peatlands, and shrublands from land- damage that poorly designed and hast- more carbon than they lose, a host use conversion should be the priority ily implemented tree plantings impose of natural climate solutions have (Temperton et al. 2019). Tree planting on ecosystems and people. been proposed to enhance carbon campaigns divert funding from con- We propose that people-centered sequestration (Griscom et al. 2017). servation toward riskier, more costly, climate policies should be developed Despite the importance of below- and less effective interventions. that support the social, economic, and ground biomass and soil organic Planting trees without addressing the political conditions that are compat- matter to carbon storage, the most social drivers that caused deforesta- ible with the conservation of Earth’s visible and easily measured carbon tion in the first place will not mitigate diversity of terrestrial ecosystems. resides aboveground in trees. The climate change because those same Such a shift in focus, away from tree high visibility and cultural resonance drivers will destroy planted forests planting and toward people and eco- of trees has led advocates to elevate or shift ecosystem destruction else- systems, must be rooted in the under- tree planting as paramount among where. Globally, the most prominent standing that natural climate solutions natural climate solutions (Veldman land-based source of carbon emis- can only be effective if they respond to et al. 2019). Unfortunately, large- sions is the expansion of commodity the needs of the rural and indigenous scale tree planting programs have agriculture (IPBES 2018). To protect people who manage ecosystems for high failure rates, resulting in wasted ecosystems from commodity agri- their livelihoods. resources and little carbon sequestra- culture, it is essential to secure the To motivate this shift in focus, we tion (Duguma et al. 2020). Worse rights of rural and indigenous people highlight ten pitfalls and mispercep- yet, planting in ecosystems with to make land management decisions. tions that arise when large-scale tree naturally sparse tree cover, such as Land rights must be coupled with planting campaigns fail to acknowl- savannas and peatlands, is destruc- economic policies that support eco- edge the social and ecological com- tive for biodiversity and counterpro- system-friendly land-use practices, plexities of the landscapes they aim ductive for addressing climate change provide just compensation for the to transform. We then describe more (Temperton et al. 2019). By focusing carbon that ecosystems store, and BioScience XX: 1–4. © The Author(s) 2020. Published by Oxford University Press on behalf of the American Institute of Biological Sciences. All rights reserved. For Permissions, please e-mail: [email protected]. doi:10.1093/biosci/biaa094 https://academic.oup.com/bioscience XXXX XXXX / Vol. XX No. X • BioScience 1 Viewpoint historically occur destroys the habitats of plants and animals adapted to open ecosystems and threatens the liveli- hoods of people dependent on those Downloaded from https://academic.oup.com/bioscience/advance-article/doi/10.1093/biosci/biaa094/5903754 by Sveriges Lantbruksuniversitet user on 16 September 2020 ecosystems to produce wild game and domestic livestock. The iconic savan- nas of Africa are a prime example of the ecosystems that are threatened by large-scale afforestation campaigns (Bond et al. 2019). In addition to the biodiversity cost, because fire and tree- killing megafauna, such as elephants, are natural forces in these ecosystems, afforestation provides less long-term carbon storage than maintaining savannas in their open state, where most carbon is protected from fire and herbivory underground. Trees can reduce water Figure 1. Government officials inspect a 2-year-old plantation of Eucalyptus availability clones on government-controlled land in Telangana, India. Low biodiversity, Advocates of tree planting often soil disturbance, exacerbated fire risk, altered hydrology, and restricted access assume that trees improve ground and to local people mean that this afforested land, although a potentially valuable surface water recharge, but the real- source of wood fiber for paper, disrupts rural livelihoods and should not be ity is more complicated: In the wrong considered a natural climate solution. places, planted forests deplete ground water and can cause streams to dry up (Jackson et al. 2005). Although trees offer incentives for governments, cor- Tree plantations sequester can facilitate water infiltration into porations, and land managers to con- less carbon, less securely, than soils, they also increase evaporation serve ecosystems (IPBES 2018). naturally regenerated forests of intercepted rainfall and transpira- Global forest restoration initiatives tion from leaf surfaces. The impact of Forests can regrow on deforested promote fast-growing plantations of trees on the balance between recharge land without tree planting commercial pulp and timber species and evapotranspiration is compli- In most places where reforestation as a natural climate solution despite cated and depends on many factors is desirable, forests can regenerate clear evidence that these plantations (Jackson et al. 2005). If a cobenefit of naturally from seeds or resprouts, lead to little long-term carbon storage a proposed tree-planting scheme is even in landscapes that appear to (figure 1; Lewis et al. 2019). Worse yet, to enhance water resources, a careful be highly degraded. Because natural widely planted species in the genera site-specific evaluation is imperative regeneration requires little human Pinus and Eucalyptus are extremely to determine whether potential gains intervention, it is usually much flammable and can exacerbate wild- in recharge will be offset by increased less expensive than tree planting. fire risk and ecosystem carbon loss evapotranspiration. Whereas natural regeneration often (Veldman et al. 2019). To be clear, fast leads to faster forest recovery, greater growing trees can serve an economic Trees can warm the atmosphere carbon storage, and more cobenefits purpose, but should not be confused Trees interact with the climate system for biodiversity and people, misap- for forest restoration or a natural cli- in ways that can cause warming to plied tree planting can hinder for- mate solution. exceed the cooling benefit of carbon est regrowth (Duguma et al. 2020). sequestration (Li et al. 2015). Trees, Where natural regeneration is insuf- Tree plantations in grasslands, particularly evergreen conifers, are ficient, assisted natural regeneration shrublands, and peatlands destroy darker and taller than most other land may involve planting a small number biodiversity covers, and therefore absorb more visi- of trees targeted to specific goals— Many ecosystems that do not naturally ble and ultraviolet sunlight (shortwave such as establishing seed sources support dense tree cover are targeted radiation) compared to highly reflec- or species that are valued by local for large-scale tree planting (figure 2; tive bare ground, snow, or grasses. people—rather than maximizing the Veldman et al. 2019). Establishing tree When trees replace highly reflective number of trees planted. plantations where forests did not surfaces, the albedo of the ecosystem 2 BioScience • XXXX XXXX / Vol. XX No. X https://academic.oup.com/bioscience Viewpoint select the trees they need, maintain their local food production systems, and secure the future benefits of eco- system conservation (Duguma et al. Downloaded from https://academic.oup.com/bioscience/advance-article/doi/10.1093/biosci/biaa094/5903754