How Trees Outside Forests Impact Well-Being Of Humans

• A new study highlights that while trees outside forests provide wide-ranging benefits, their long-term impacts on human well-being are poorly understood.
• Along with being a source for commodities such as timber and fuelwood, trees outside forests are important for biodiversity conservation and carbon sequestration.
• Most of the publications reviewed for this study indicated that these trees lead to an increase in human well-being outcomes. However, there were also negative impacts on sense of agency, political voice, and social equity.

Trees outside forests in places such as farms and grazing land, provide a wide variety of benefits to humans. Yet, there is limited understanding of how tree restoration impacts health, education, the economy, social well-being, and material outcomes — especially in South Asia, which has great potential for restoring trees. A new study published in the journal Environmental Research Letters highlights this gap and offers insights to guide ongoing and future tree-based natural-climate solutions projects in the region.

With the world facing escalating threats of climate change, tree planting has emerged as a popular solution. In India, the growing emphasis on tree planting initiatives to reduce carbon dioxide in the atmosphere has led to a rise in trees outside forest systems (ToF). These trees comprise 37.11% of India’s total tree and forest cover. India’s Forest Survey Report 2021 showed trees outside forests have increased by 13.09% from 2015, a stark contrast to growing stock inside forests, which saw a rise of only 4.60%. This indicates a shift in where trees are being planted.

“There is a tree planting frenzy in the country and around the world, which is also surprisingly largely driven by ecologists. Beyond the carbon benefits, it makes me wonder whether there is interest in it because we can map it more easily. As we have breached the 1.5°C climate target, people seem to want to grab onto things that can be seen, counted, put in a report, and shown, such as trees,” says Pooja Choksi, ecologist and lead author of the paper.

Understanding trees outside forests

With increasing focus on tree planting, the new paper emphasises the importance of understanding the wide range of human well-being outcomes, both negative and positive of trees outside forests, to inform ongoing and future tree planting programs or other policy interventions.

This lack of understanding of human well-being aspects of ToF systems as pointed by the study is more to do with a lack of formal, scientific articulation, shares Jayashree Ratnam, Director of the Wildlife Biology and Conservation Program at the National Centre for Biological Sciences.

The authors define ToF as trees outside government-owned and managed forest land. As noted by the Forest Survey of India, these include trees along roads and canals, small woodlots, block plantations, and trees on farmlands, agricultural lands, homesteads, community lands and urban areas. Along with being a source for commodities such as timber and fuelwood, they are important for biodiversity conservation and carbon sequestration. As per India State of Forest Report 2021, the total carbon stock in the forest is estimated as 7,204 million tonnes and of this, trees outside forests contribute 529.47 million tonnes.

Trees outside forests support and regulate ecosystems through services such as water and soil conservation, microclimate regulation, and natural resources for consumption, Choksi and team note in the study. “I believe when people started thinking of climate solutions, trying to tackle food security and other climate-related issues, the focus on trees outside forests strengthened. Specifically, there has been a push from people using remote sensing data to monitor the trees as a good source for carbon storage,” she added.

But trees outside forests often don’t receive the same attention as forests because they are difficult to define, the World Resources Institute explains. Moreover, there is less emphasis on individual trees, especially isolated ones or those growing in the middle of farmland, says Jagdish Krishnaswamy, Dean, School of Environment and Sustainability (SES) at Indian Institute for Human Settlements (IIHS).

“Now people are also trying to grow trees in industrial estates. For instance, in industrial warehouses in India, a certain percentage of land must be kept open, where often trees or other vegetation can be grown. Moreover, in hospitals, military or educational campuses in rural and urban areas, there are large trees, and there is an opportunity to grow more of them, which is often not recorded in assessments,” Krishnaswamy explains.

Although there is increased focus on trees as a natural climate solution, ToF systems such as those growing in farmlands are showing a worrying trend. A 2024 study published in the journal Nature Sustainability showed that from 2018 to 2022, India may have lost over five million full-grown trees in farmlands. Moreover, 11% of large trees mapped from 2010 to 2011 had disappeared by 2018. The study authors note that this is unsettling given the current emphasis on agroforestry as a vital tool for climate mitigation.

Talking about the study’s findings, Krishnaswamy emphasises that large trees that take many years to grow, are irreplaceable. “Even if you plant a thousand saplings after cutting a huge native tree, it is not going to give us the level of benefits such as terms of biodiversity, benefit, carbon benefit, or shade. It will take decades to achieve these benefits,” he explains.

Impact on human well-being

Despite South Asia having strong cultural norms of growing trees outside of forests, such as using live fences and growing diverse trees in backyards, human well-being outcomes are not well documented.

Choksi and team reviewed 325 articles using six databases using the PICO (Population, Intervention, Comparator, Outcomes) framework and predominantly found a positive effect of ToF systems in South Asia. Out of these, 71% of articles focused on India and Bangladesh. The review showed that tree or forest gardens and multipurpose trees on farmlands were the most studied ToF systems in the region.

Most of the reviewed publications indicated an increase in human well-being outcomes, such as economic well-being (84%), which suggests that ToF systems are not just ecological assets but economic ones too. Material benefits were also prominent, with more than 80% of studies that focused on access to biomass and fuelwood reported positive outcomes, indicating the importance of ToF systems to meet household needs. About 83% of studies reported improved dietary diversity because of ToF systems, which is often through access to variety of food or increased income for households to afford a broader range of food. The review also showed that leisure-related outcomes such as access to nature were the least studied.

Negative outcomes 

Although economic benefits were the most studied outcomes, Choksi voiced concerns about their long-term sustainability. “We found evidence of monetary benefits associated with ToF, but it seems like there is money to plant trees, but is there enough to maintain them? Since practically all the papers we reviewed were one-time assessments, we could not tell. But it’s important to look into how long monetary benefits last,” says Choksi.

She also added that while trees do create economic prosperity, the question that often arises is whether these benefits are equitably distributed. “The paper indicates that some ToF systems can increase inequity and disrupt certain communal relationships,” she explains.

The study also found negative outcomes on sense of agency. A 2022 study by Laura Valencia in Odisha found that not everyone felt they got to voice their opinion when government-led tree planting projects were coming up. “This was a classic case of elite capture,” Choksi adds.

The review also brings into focus the harmful impacts of top-down approaches. In rural areas of Bangladesh, often self-help groups were created, and they were handed seedlings and saplings to use in people’s backyards to plant in different places, including private and communal land. But local people were not consulted to determine what would be planted and where. Moreover, men in higher socio-economic classes dominated the self-help groups, furthering social inequity in benefits.

“Most of the negative social outcomes were associated with afforestation, and these were mainly because of governmental tree planting programmes that were top-down. There needs to be more involvement of communities, grassroots ideation and bottom-up work,” Choksi explains.

Need for thoughtfully designed interventions

To address the negative trade-offs of trees outside forest systems, the study underscores the need for more thoughtfully designed interventions to achieve both ecological and human well-being outcomes.

Like Choksi, Ratnam also emphasises the importance of involving communities in designing ToF systems that can be natural climate solutions. “Ecologically speaking, not all ecosystems on Earth are meant to have lots of trees. Local communities with a long history of being in a landscape can help identify regions where ToF systems can be beneficial, as a climate solution and for them,” says Ratnam.

There are many ecosystems, notably open grasslands, alpine meadows, and natural deserts, where tree planting may not provide the above-ground carbon benefits as often assumed and can even lead to losses in below-ground soil carbon. And in arid and very arid regions, it can even compromise hydrological security, she further explains.

Krishnaswamy highlights these concerns using a study he co-authored in 2021. Focusing on central India, the team looked at potential hydrologic impacts of abandoned agricultural paddy land being converted to tree plantations. In such landscapes, the net hydrologic benefits go up initially due to higher infiltration and groundwater recharge. “But after you cover a certain threshold of the landscape with trees, the transpiration requirements of trees exceed the recharge benefits. We have to be mindful of the types and density of trees being planted depending on the climate of the area,” he explains.

Ratnam stresses the need for understanding the order of priorities of where people can plant trees for maximum benefit without compromising any of the kinds of hydrological or ecological security, such as losing soil carbon.

“The focus should first be on planting trees in urban areas, then in towns and villages. This should be followed by tree planting along highway edges, then alongside farm edges. Lastly, in regions where food security is not compromised by switching to some degree of agroforestry,” says Ratnam. Moreover, she adds, trees planted along roads should be diverse instead of lining entire avenues with the same trees.

To enhance the capacity of trees and other vegetation as natural climate solutions and their ecological benefits, Krishnaswamy points out the importance of conserving existing natural and semi-natural forests but also restoring grasslands and wetlands. In tree planting initiatives or ecological restoration, there should also be a combination of trees, shrubs, and grasses in our re-vegetation or restoration schemes, Krishnaswamy adds.

Choksi concludes with a call to start small and local. “Instead of large-scale plantations, we could increase trees in our surroundings, like our backyards. We could also focus on reviving tree species dwindling in numbers. Through them, you can also revive a lot of traditional, and largely forgotten, food cultures around it.”

(Published under Creative Commons from Mongabay India. Read the original article here)