Scientists lay out 10 golden rules for restoring forests

Scientists from the Royal Botanic Gardens, Kew (RBG Kew) and Botanic Gardens Conservation International (BGCI) have set out ten ‘golden rules’ for reforestation, published today in an open-access article in the leading journal Global Change Biology. These rules have been set by the experts in response to the damage some large-scale tree planting schemes are seen to be inflicting on the environment and to provide nature-based solutions to protect and restore global forests. The list highlights how forests can be restored with the simultaneous triple benefit of maximising carbon capture to mitigate global warming, recovering ecosystems, and helping people’s livelihoods.

Dr Kate Hardwick, Conservation Partnership Coordinator at RBG Kew and a lead author of the paper says: “Tree planting now dominates political and popular agendas and is often presented as an easy answer to the climate crisis, as well as a way for corporate companies to mitigate their carbon emissions, but sadly, it isn’t as simple as that. When people plant the wrong trees in the wrong place, it can cause considerably more damage than benefits, failing to help people or nature. Our paper sets out to look at these issues and create a framework for people, businesses and policymakers to use for future reforestation projects that can aid both people and the environment.”

This paper comes out ahead of a virtual conference next month, held by RBG Kew and BGCI, Reforestation for Biodiversity, Carbon Capture and Livelihoods which will run over three days from 24 – 26 February 2021. The event, with Sky Zero as headline sponsor, will bring together a series of interesting global perspectives to debate and challenge the myth that ‘all tree planting is good’ and to discuss best practice for protecting and restoring the world’s forests. The conference will be opened by HRH The Prince of Wales and it is hoped the discussions will raise the standard of reforestation globally and support discussions in the run up to - and initiatives arising from - the critical agenda-setting UN conferences (COP15 and COP26) later this year on new global biodiversity and climate change agreements.

Professor Alexandre Antonelli, Director of Science at RBG Kew and senior author of the paper says: “Forests are crucial to all life on Earth. They provide a home to 75% of the planet’s plants and animals, they provide us with food, fuels and medicine and are incredibly important for our mental health and wellbeing. But they are disappearing at an alarming pace; we lose an area of tropical rainforest twice the size of Wales every year. It is therefore fantastic that thousands of people and businesses are planting trees. Our paper doesn’t set out to say that tree planting is wrong, it is a brilliant solution to tackle global warming and protect biodiversity, when done correctly and effectively. Instead, we want our paper and upcoming conference to challenge the way we currently plant trees so that we can maximise impact and herald a new era for the world’s forests that benefits everyone. And whenever there’s a choice, we stress that halting deforestation and protecting remaining forests must be a priority.”

There are many ambitious tree-planting initiatives underway across the globe, all of which aim to capture enormous quantities of carbon to compensate for the huge CO₂ emissions that are a major cause of rising global temperatures. The authors looked at such initiatives and found that in some cases planned tree planting does not actually increase carbon capture and can have long-term negative impacts on biodiversity, landscapes and livelihoods.

One such example is in South Africa, when the non-native Australian acacias were introduced for dune stabilisation and timber during the 19^th and 20^th centuries. The acacias became invasive, spreading widely across vast areas of land, taking over the natural heathlands and grasslands and lowering the water table. It now costs the country the equivalent of millions of pounds to clear them every year.

The scientists’ ten golden rules set out below aim to ensure that new and restored areas of forest become effective, long-term carbon sinks, stop the loss of forest biodiversity and support the livelihoods of local people. The rules cover all stages of the reforestation process, from selecting the right site and the right species, through to using the forest to generate a sustainable income for local people. They emphasize the importance of protecting existing forest and working collaboratively.

10 Golden Rules for Restoring Forests (set out in detail below)

1. Protect existing forests first
2. Put local people at the heart of tree-planting projects
3. Maximise biodiversity recovery to meet multiple goals
4. Select the right area for reforestation
5. Use natural forest regrowth wherever possible
6. Select the right tree species that can maximise biodiversity
7. Make sure the trees are resilient to adapt to a changing climate
8. Plan ahead
9. Learn by doing
10. Make it pay

Dr Paul Smith, Secretary General at BGCI and co-author of the paper says: “These ten rules highlight that planting trees is highly complex. There is no universal, easy solution to a successful reforestation initiative given the extraordinary diversity of trees, forest types and the unique cultural and economic environments each forest is in. However, there are successful examples that we can learn from and develop further to build on current public and private interest in the topic. The past 30 years of research and practice has given us the tools to feasibly restore millions of hectares of forest around the world if these 10 golden rules are taken into consideration. Planting the right trees in the right place must be a top priority for all nations as we face a crucial decade for ensuring the future of our planet.

2. Put local people at the heart of tree-planting projects

Involving local communities as part of the stakeholder engagement is imperative, say authors of the paper. Best practice for community involvement in a reforestation project means involving local people right at the beginning, from the planning stage through to delivery and management of the forest. Previous studies of global forestation projects cite lack of community involvement as one of the most common causes of project failure.

Increased engagement with local people increases the positive outcomes of a project, creating fair and equal benefits to the community. For example, it is local communities that will often look after the forest, prepare the land, plant the trees, and maintain the site, all of which diversifies local employment and improves livelihoods. There are also further benefits to the community around wellbeing, natural capital and increased knowledge.

The authors found several examples of successful tree-planting schemes with local people at the heart of them, including a community-based forest management project in Nepal, a system called ‘ngitili’ in Tanzania that uses traditional local knowledge to underpin collective land management, and a community-led reforestation project using local indigenous species in eastern Madagascar where members of the community worked together to restore areas degraded by fire and over-exploitation.

4. Select the right area for reforestation

Even though reforestation is always implemented at the local scale, decisions can often be made at a global scale, especially with the emerging engagement of international organisations in tree-planting initiatives. In the paper, the scientists advise that global decisions on which area to reforest should address key criteria such as avoiding previously non-forested lands, connecting reforested sites to existing forest to expand the forested area where possible and being aware of displacing activities that could cause deforestation elsewhere.

Ultimately, the best area for planting trees would be a previously forested land that has become degraded, avoiding non-forested landscapes such as natural grasslands, savannas or wetlands whose own individual ecosystems already contribute greatly to capturing carbon, mostly in the soil. It would also be in an area where trees could deliver other ecosystem services, such as recreational spaces, wildlife habitats, clean air and shade, whilst avoiding areas which could displace agriculture forcing further deforestation or social conflicts elsewhere.

The authors recognise that more tools are needed to help guide reforestation and make better decisions. Maps identifying high-priority areas for intervention, developed as a result of pledges to the Bonn Challenge, are a great start. Advances in remote sensing and drone technology are also helping to prioritize and monitor areas of degraded forest for restoration. Scientists at Kew are currently using these technologies in Brazil and Peru, to identify and quantify how natural habitats are being devasted by human activities and climate change.

6. Select the right trees that can maximise biodiversity

When natural regeneration is not possible and tree planting is needed to restore forest, picking the right trees is crucial say the scientists. They advise that a mix of species should always be planted, typical of the local natural forest ecosystem and including rare and endangered species, in order to create a rich ecosystem.

Maximising biodiversity depends not only on the number of species reintroduced but also on the functions they perform. The authors suggest prioritising trees that provide mutualistic interactions, such as those between native tree species and fungi, seed-dispersing animals and pollinators, is vital to achieving a resilient, biodiverse and restored environment. Avoiding exotic species that could become invasive is also imperative – invasive species are an important driver of the current global biodiversity crisis. They have long-term effects on the environment, competing with native species, reducing biodiversity and often reducing the water availability.

A good example where the right trees were picked to achieve a restored forest with mutualistic interactions is in Lampang Province in northern Thailand. A previously forested site which had been degraded through limestone mining was restored by Siam Cement Group and Chiang Mai University. After spreading 60 cm of topsoil, they planted 14 different native tree species including several species of figs, and legumes to improve the soil conditions. By the end of the third rainy season, canopy closure had been achieved and macaque monkeys started visiting the plot to eat the fig fruits, naturally dispersing the seeds of other species through defecation. Overall, the trees had an average annual growth rate of 91%.

8. Plan ahead

Whether restoring a forest with tree saplings or tree seeds, appropriate infrastructure and seed supply systems are essential. Deciding in advance where to source seeds or purchase trees needs to be planned for. Projects must be prepared to develop their own seed collections or storage and propagation capacity, if not available regionally. Likewise, with saplings, in-house nurseries need to be built or an accredited nursery found that can help. The authors suggest it is always best to work with local people as they are important sources of labour and expertise.

10. Make it pay

Income generation by selling forest products from livelihood forests is easily achieved, whereas marketing environmental services from existing and restored native forest is more difficult, say the authors, especially in protected areas. The sustainability of forest restoration depends on the income streams generated from it exceeding those from alternative land-uses, and on that income being shared fairly among all stakeholders, including the poorest.

The authors cite the UN’s REDD+ strategy (a voluntary climate change mitigation approach to reduce emissions from deforestation and forest degradation and to enhance forests as carbon sinks in developing countries) as making some progress in monetizing forests as carbon sinks. Forest carbon value alone often exceeds revenue from the main drivers of deforestation such as palm oil, but application of REDD+ to incentivize reforestation has been challenging at times due to governance issues and socio-economic conditions, often not benefitting all stakeholders. Revenue could also be generated from other ecosystem services provided by forests, such as the protection of river catchments in upland areas. However, this would require increased awareness and marketing to drive financial investment into the natural capital services provided by restored forests.

To ensure revenue flows mostly into local economies, local people should have direct access to carbon markets and start-up loans to fund restoration work, minimizing the role of third-party agents. Ecotourism can also be lucrative for local income, directly monetizing biodiversity, but again substantial start-up funding is needed, and skilled labour is required to meet the demands of ecotourists.

To register your place at Kew and BGCI’s ‘Reforestation for biodiversity, carbon capture and livelihoods’ conference, visit www.kew.org/reforestation-conference. Registration is free.