The Royal Botanic Gardens, Kew and Botanic Gardens Conservation International (BGCI) have a forthcoming conference on Reforestation for Biodiversity, Carbon Capture and Livelihoods. As a part of it, a paper has been recently published in Global Change Biology Ten golden rules for reforestation to optimize carbon sequestration, biodiversity recovery and livelihood benefits by Alice Di Sacco, Kate A. Hardwick and colleagues. The title gives away the contents, though not the complexity of the issues that the conference will cover.
Reforestation is seen as a major tool in combating anthropogenic carbon dioxide emissions. However, it’s not a simple matter of putting trees in the ground. Di Sacco & Hardwick et al. start the paper by emphasizing the complexity of forests. They point out that the trees interact with animals, and microbes as well as abiotic events like fire and flooding. Navigating through this complexity is helped by a glossary of terms used in the paper. While they define various kinds of forest, the only missing term is forest itself.
Given the difficulty in recreating the complicated relationships between all the organisms in a forest, it’s no surprise that rule one is Protect existing forest first. It’s an approach the authors call proforestation, taking the term from a recent paper by William Moomaw and colleagues. Proforestation grows existing forests ‘intact to their ecological potential’, according to Moomaw et al.
Di Sacco & Hardwick et al. propose two other foundational rules, Work together and Aim to maximize biodiversity recovery to meet multiple goals.
Having multiple goals sets out what the reforestation project will do. The authors state that reforestation is not an end itself. It is necessary to ask what the reforestation is planned to achieve. Working together, comes into this as one question would be whose goals do you aim to achieve? Working with local communities is vital from the planning stage, say Di Sacco & Hardwick et al. It’s also important to note that they don’t see communities as homogeneous blocks.
“They comprise groups of people differentiated by wealth, ethnicity, gender and other socio‐economic stratifications that have different power relations and interests in the reforestation process. For instance, in some countries, men and women have different rights to land and trees, which affects those with insecure rights, mostly women, from effectively participating in reforestation activities. It is essential to consider those inequalities, as well as conflicts between private, communal and political interests.”Di Sacco & Hardwick et al. 2021
Next comes a series of rules where biology is brought to the foreground, Select appropriate areas for reforestation, Use natural regeneration wherever possible, Select species to maximize biodiversity, Use resilient plant material, and Plan ahead for infrastructure, capacity and seed supply.
Reading it, adding ‘wherever possible’ to ‘Use natural regeneration’ makes one of the Golden Rules feel more like a Golden Guideline, but the authors bring plenty of evidence to justify the qualification. One example that stood out was the use of eucalypts in Brazil. I would have thought that eucalypts were a poor choice for reforestation. Di Sacco & Hardwick et al. cite work by Pedro Brancalion and colleagues on the use of eucalypts in the Atlantic Forest of Brazil.
This was work conducted at a number of sites in Brazil. In some plots native trees were planted. In others, a mix of native trees and eucalypts were planted. In these plots, the eucalypts were harvested after five years. The results were that the trees in the mixed plantations were either unaffected or only slightly affected the eucalypts, which grew tremendously during the first five years. After the harvest the plots continued to regenerate, ending up in a similar state to the purely native plots after a decade or more.
Brancalion et al. do discuss some negative impacts from growing the eucalypts. “A valid concern about interplanting eucalypts with native species is that falling trees and dragging logs could damage the native non‐pioneer trees interplanted with eucalypts and the abundant natural regeneration of the understory. In fact, the visual impression right after logging was that all regenerating individuals were destroyed in eucalypt planting lines, where logging impacts were concentrated.”
Other problems with eucalypts are that they’re thirsty trees, and prone to intensifying fires. In this case, Brancalion et al. point out that the Atlantic Forest is a wet forest. While planting eucalypts in some locations would be a staggeringly bad idea, in this part of Brazil, it may be workable. The eucalypts are not inherently bad, Brancalion and colleagues say, but the forest management has to be right to make mixed planting work.
But why, given the problems would someone want to bring in eucalypts, if they make little ecological difference. The answer is money. Brancalion et al. found that eucalypt harvesting paid for around half or more of the reforestation costs.
This brings us back to two of the more human golden rules, Learn by doing and Make it pay. This last rule has caught the eye of Gabriel Hemery, “It reminds me of a common adage used in British forestry—not the right tree in the right place for the right reason (which is always helpful)—but that a tree that pays is a tree that stays.”
Making reforestation pay isn’t simply a matter of managing the harvest. Di Sacco & Hardwick et al. stress the importance of diverse income streams. There’s a lot of realism in this section. I’ve seen plenty of people state that ecotourism is the future for some areas. The authors are sceptical of the income, saying its potential is often overestimated. “Furthermore, the skilled labour required to meet the discerning demands of ecotourists is often imported from outside, sidelining local people.”
The complexity of making reforestation sustainable makes the point Learn by doing important. The authors describe the importance of experience, including indigenous experience in combination with scientific trials. While there may not be absolute answers, Di Sacco & Hardwick et al. make clear that measuring success against targets is a key part of the learning process.
While the graphic with the list of points has got a lot of attention, the final figure is also of interest. The ‘final state’ of the reforestation process envisioned isn’t a final state at all, but part of an ongoing process. Protected forest sits near restored forest, with livelihood forest harvested and used while regeneration happens in other areas. Reforestation, in this view, isn’t a goal that’s achievable. It’s a process that makes goals achievable. Reforestation is an interaction between trees and other species.
Thinking about what a forest is, it’s more than the sum of its parts. Dumping a batch of trees, some fungi, undergrowth and a few animals into a location won’t get you a forest. It’s the relationships working together than turn the biological material into something more. In a similar vein, Alice Di Sacco, Kate A. Hardwick and colleagues demonstrate that reforestation isn’t simply about adding trees, but also about an ongoing relationship between the trees, wildlife and the humans that live alongside or within it. Done correctly, the forest is more than the sum of its parts.
In a similar way, one of the successes of this paper is that while the rules are thoughtful, so is the way they work together. The rules aren’t isolated but support each other. This integration makes them much more useful than isolated instructions and help guide cohesive projects.
You can sign up for the conference till 12pm GMT February 19, 2021. If you’re taking part, then this paper will be an excellent introduction to the aims of the conference and the topics it will tackle.