Guidance for successful tree planting initiatives

Abstract

1. A growing number of initiatives at global, regional and national scales propose to plant millions, billions or even trillions of trees as a simple solution to resolve complex environmental problems. However, tree planting is much more complicated than it seems. 2. We summarize the multifaceted decision-making process needed and offer guidelines to increase the success of the proposed ambitious efforts to increase tree cover worldwide. 3. Given the varied definitions of and motivations for tree planting, it is critical that stakeholders work together to clearly define the biophysical and socioeconomic goals of each project. Then a series of questions must be addressed about where and how (e.g. planting trees vs. allowing for natural forest regrowth) to most effectively achieve these goals and minimize unintended negative consequences, as well as how, when and by whom success of efforts will be evaluated. 4. Key guidelines to successfully increase tree cover include: (a) first addressing the underlying drivers of deforestation; (b) integrating decision-making across scales from local to global; (c) tailoring tree planting strategies to clearly stated project goals and planning, adaptively managing and evaluating success over a sufficiently long timeframe; (d) focusing on the forest ecosystem as a whole, and not just the trees; (e) coordinating different land uses and (f) involving stakeholders at all stages of the planning process. 5. Synthesis and applications. Tree planting, along with other strategies to increase tree cover in appropriate locations and contexts, can make a valuable contribution to ensuring the ecological and social well-being of our planet in coming decades, but only if these efforts are considered as one component of multifaceted solutions to complex environmental problems and are carefully planned, implemented and monitored over a sufficiently long timescale with stakeholder engagement and broader consideration of socio-ecological complexities.

Hidden destruction of older forests threatens Brazil’s Atlantic Forest and challenges restoration programs

“…The most favorable areas for restoring tropical rainforests in the world coincide with those with higher conservation priorities ( 26 ), which reinforce the need to favor forest restoration with native species ( 11 ) and the implementation of forest protection interventions as part of restoration programs ( 53 ). We here demonstrate how native and exotic tree covers can be differentiated, native forest cover can be classified according to age, and the impacts of native forest cover dynamics on habitat isolation can be assessed, which are crucial elements for the accountability of the several ambitious forest restoration programs planned for the next decade.…”

Managing forest regeneration and expansion at a time of unprecedented global change

“…To offset long‐term deforestation world‐wide, there are at least three ongoing initiatives aiming to ensure the environmental societal well‐being of the planet by planting 1 trillion trees (Brancalion & Holl, 2020). These initiatives should be long‐term commitments to restore forest cover, ES and biodiversity but frequently their success is merely evaluated as the number of planted trees.…”

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“…However, it might be that some of the identified initiatives who apparently only finance tree planting, also support other FLR approaches but chose to not specifically mention this on their website to simplify communication. The disproportionate focus on tree planting in eco-marketing initiatives may be problematic in situations where other FLR interventions have higher potential to lead to ecological, and/or socially beneficial outcomes (Brancalion and Holl, 2020). Especially in ecosystems where trees are already present, assisted natural regeneration can be a more effective strategy from both a financial and biodiversity perspective (FAO, 2015;Brancalion et al, 2016;Chazdon and Guariguata, 2016;Crouzeilles et al, 2017).…”

“…Furthermore, the information provided by the eco-marketing initiatives did not always disclose if trees are planted in monoculture plantations or not. If trees are planted in (exotic) monocultures, the establishment of tree plantations might replace native forests or cultural lands where forests might have naturally regenerated, and lead to overall negative environmental impacts (Lewis et al, 2019;Brancalion and Holl, 2020;Heilmayr et al, 2020). This issue is enhanced by the way our global targets are designed, namely in numbers of trees planted (e.g., the Trillion Trees Campaign) or hectares restored (e.g., the Bonn Challenge).…”

“…This momentum can be leveraged in a way that could have strong positive impact on ecosystems, our climate, and livelihoods, but it is important to emphasize the potential risks that come with large financial flows being channeled to tree planting specifically. For this reason it is necessary that strong safeguards are in place to promote tree planting in places where it is socially, environmentally, and ecologically beneficial, and to make sure on-the-ground context is understood before a restoration project is executed (Brancalion and Holl, 2020). In addition, for successful restoration, it is essential that not only the tree planting itself, but also follow-up maintenance (e.g., tending and irrigation) is facilitated to prevent high mortality rates in the first years after planting (Kettle, 2009).…”