The word “ecology” is a combination of the Greek words “oikos” and “logos.” In the past one and a half-century, the complex network interconnecting humans and the environment has always been ecology’s distinguishing feature. While ecology is perhaps the most economical discipline besides “economy,” large-scale tree planting that has been hurriedly implemented in recent years is destroying this criterion. Although people have already witnessed the failures of tree planting plans in Africa, China, and Sri Lanka (Holl and Brancalion 2020), policymakers, scientists, and celebrities have consistently failed to learn these lessons. Forest restoration is a natural solution that is effective in mitigating climate change and the prevailing thought is that the amount of CO2 absorbed is proportional to as many hectares or trees that are planted. However, this analysis has not fully considered the key role of people in maintaining forestation. Recently, through critical investigation, Fleischman et al. (2020) has shown that without consideration for the role of people, forest restoration is essentially doomed to failure.
The authors concisely discussed the financial issues, and the “economy” of carbon, water, and temperature. For example, although the Payment for Ecological Services (PES) plan has been implemented for many years, it has failed to secure the rights of rural and indigenous people to make land management decisions. While afforestation is implemented in one place, commodity agriculture is being encouraged in other places and the overall afforestation area may eventually decrease. Furthermore, the litter of Pinus and Eucalyptus trees planted over large areas is extremely flammable, which greatly increases the possibility of wildfires, ultimately increasing carbon emissions (Fleischman et al. 2020). In fact, trees planted in grasslands, savannas, and peatlands have higher mortality rates (zero survival rates) owing to drought-induced embolism and subsequent hydraulic failure. They not only failed to absorb CO2, but also destroyed precious wild landscapes that not only harbor mega-biodiversity, but also play a role in mitigating climate change. In reality, some deforested areas will naturally grow into forests even if people do not reforest. By the mid-21st century, more than 5 billion people worldwide will face water shortages. Water shortage areas are not only in arid and semi-arid regions but also in tropical areas, especially in high mountainous areas. Planting trees in these areas, especially fast-growing trees for commercial use will accelerate both the depletion of groundwater and the recycling of rainfall within the atmosphere by dense canopies, thereby reducing surface runoff and water supply. It is not cost-effective to plant trees in high latitudes or alpine areas that also have significantly higher air temperature due to lower albedo than bare lands (e.g., dark coniferous forests). This will accelerate climate warming, resulting in the melting of permafrost and permanent snow, which increases the risks of landslides, avalanches and glacier floods. These climatic disasters will be devastating to people who are already relatively poor.
As mentioned above, the key to the success of forestation plans is involvement of local residents in its management, not only for them to be paid in the short term. Planting trees without maintaining them is an important reason for reforestation failures. Indeed, the premise is that these trees are planted in areas with suitable climatic conditions to support the growth of the forest (e.g., with an annual precipitation > 400 mm). The consequence of promoting unsustainable tree planting plans is the ruin of the local crops, which leads to loss of employment and livelihood, which must be avoided. People in poorer countries of the southern hemisphere have no moral obligation to plant trees and reduce arable croplands to help the richer countries in the northern hemisphere absorb CO2, even in the name of mitigating climate change effects and stimulating sustainable development for society.
Therefore, the key to solving these problems is to obtain the support of local people, by securing their land rights and enhancing their political power. A better way for local people to actively participate might involve planting short-statured, resilient, and drought-resistant shrubs with high economic value. Improving livelihoods and the quality of life must be incorporated into forest restoration frameworks. For achieving green, economic, and sustainable revegetation, poverty eradication is a prerequisite. Only tree planting of the people, by the people, for the people, shall succeed in global forest restoration.
Gao, J.G. (2020) Tree Planting of the People, by the People, for the People. BioScience. https://doi.org/10.1093/biosci/biaa095