Is the Forestry Industry Capable of Mitigating Global Warming?

The idea of tree planting is gaining popularity as a potential solution to address global issues like pollution, surging carbon emissions, and declining soil health caused by climate change. However, various studies emphasize that tree planting alone is not a cure-all for reversing climate change and global warming. Successful tree planting involves more than just putting saplings in the ground; it requires careful selection of tree species, ongoing monitoring and management of saplings, and strategic planning for large-scale initiatives.

Authors of the Working Group II report from the Intergovernmental Panel on Climate Change (IPCC) issued a warning that poorly designed and unscientific tree planting efforts may lead to maladaptation. Maladaptations can increase the risk of unfavorable outcomes, such as higher greenhouse gas emissions, altered sensitivity to climate change, and social inequality. Additionally, such interventions may compromise ecosystem resilience, biodiversity, and ecosystem services.

The process doesn't end once trees are planted. Seedlings often require ongoing care and maintenance before they become robust and independent, actively sequestering carbon. Despite their significance, the maintenance and long-term monitoring of tree planting initiatives are not yet integral components of campaigns and programs.

Studies in the Central Himalayas and along India's Coromandel coast revealed significant variations in the survival rates of planted trees over five to ten years. The survival of planted saplings ranged from 51 to 87 percent at one location, 0 to 100 percent at another, and 35 to 100 percent at a third site, depending on factors such as whether the species were native or invasive and whether the plantation was mixed or mono-species. While achieving 100 percent sapling survival over five years may seem promising, it's a rarity among species.

What factors contribute to the success or failure of various plantation projects?

A key reason for the limited survival of saplings in the aftermath of large-scale planting initiatives is their unsuitability for the specific environments where they are placed. This can result from the use of low-quality seeds and saplings or, in other cases, poor planning, such as planting inappropriate tree species in unsuitable locations.

Moreover, there are instances where a significant number of compensatory afforestation schemes, approved by the environment ministry for clearing forests for industrial or mining projects, are alleged to be nonexistent. In some cases, these supposed afforestation areas, often depicted on maps, resemble ghost plantations situated in the middle of the Arabian Sea. This is either because they were never utilized for planting or have been neglected and are no longer maintained.

Certain regions witness hastily executed tree planting campaigns involving fast-growing species like eucalyptus, pine, or acacia, with the aim of "recharging the groundwater table" or "enhancing biodiversity." Ironically, these plantations often consume more water than they conserve. In some instances, such initiatives may inadvertently harm biodiversity, as seen in Chile where commercially valuable tree planting led to the destruction of ecologically significant forests. Adding to the issue, many of these plantations are located in regions erroneously labeled as wastelands or degraded forests when, in reality, they are predominantly savannahs or grasslands. Contrary to the misconception, savannahs play a vital role by hosting unique ecological niches, exhibiting superior carbon sequestration compared to artificial trees, and supporting pastoral communities.

The efficacy of trees in mitigating global warming is exaggerated

The global push for tree planting arises from the belief in the significant services trees provide. This enthusiasm permeates local initiatives, national business programs, and global campaigns like the Trillion Trees initiative. Despite the widespread misconception that reforestation and tree planting can effectively extract carbon from the atmosphere, scientists caution against oversimplifying this process. While trees indeed act as vital carbon sinks, extensive research suggests that the potential of trees to substantially decelerate global warming by absorbing up to 200 gigatons of carbon has been overly emphasized.

A comprehensive 2019 study published in Science suggested that the Earth could potentially accommodate an additional 0.9 billion hectares of forest. However, four independent comments published in Science by different scientific groups raised significant concerns about the assumptions used in the study. Notably, large portions of the area classified as "open" for tree plantations included savannahs, already crucial carbon sinks. The study was accused of a five-fold overestimation of trees' carbon storage capacity.

A 2020 Nature article by scientists highlighted an unsettling trend. The accelerated growth rate, triggered by higher atmospheric carbon dioxide (CO2) levels, leads to trees dying at younger ages. This phenomenon is attributed to a universal growth-lifespan trade-off observed in nearly all organisms, linking increased growth to earlier mortality. Consequently, while trees may absorb carbon at the current rate in the short term (this century), a delayed pattern of mortality is projected to offset these carbon gains over an extended timeframe.

What methods can be employed for the effective planting of trees?

Despite concerns, there are numerous benefits associated with tree planting. However, the focus should shift from afforestation (establishing new forests) to reforestation (restoring existing forests). Proactive restoration efforts can contribute to the rehabilitation of fragmented forests and, when carefully planned, may support local livelihoods. A study conducted in Valparai, Tamil Nadu, suggests that forests regenerated through reforestation with native species, as opposed to monoculture tree plantations, exhibit superior capabilities in carbon sequestration and storage.

Addressing deforestation is crucial in addition to reforestation. Approximately 1.5 gigatons of carbon (GtC), accounting for around 10% of the global carbon emissions of 11.3 GtC in 2017, resulted from changes in land use, predominantly deforestation. A recent study in Nature Sustainability indicates that carbon emissions from deforestation doubled between 2015 and 2019, suggesting a potential underestimation. Most of this loss occurred in tropical regions, raising concerns that, if not curbed by 2050, deforestation could jeopardize the Amazonian rainforests' role as carbon sinks.

It is evident that nature-based initiatives, whether involving tree planting or advocating blue carbon methods for mitigating climate change, will fall short without coordinated efforts aligned with policies focused on decarbonizing economies.