The importance of old growth forests

Forest conservation and restoration are critical for addressing the climate crisis, as highlighted by a comprehensive study in the journal Nature. This research, involving numerous forest ecologists, emphasizes that if greenhouse gas emissions are significantly reduced, existing forests can sequester about 226 gigatonnes of carbon, akin to nearly 50 years of U.S. emissions as of 2022.

The key strategies include protecting existing forests to mature into old-growth ecosystems and restoring degraded areas. However, the study cautions against relying on monoculture tree-planting and offsetting as means to achieve this potential.

The study notes that half of Earth’s forests have been lost, with continued destruction in vital regions like the Amazon and the Congo basin. About 61% of the carbon sequestration potential lies in safeguarding standing forests, allowing them to develop into ecosystems like Poland and Belarus’s Białowieża forest or California’s sequoia groves. The remaining 39% can be achieved by restoring fragmented or cleared areas.

The researchers stress the importance of biodiversity in helping forests reach their carbon drawdown potential. They warn against the inefficacy of planting single species and underscore the urgent need to cut fossil fuel emissions. The increasing number of forest fires and rising temperatures could diminish this potential.

Lidong Mo, a lead author, emphasizes that ending deforestation is crucial for restoring global biodiversity. Despite commitments like the Cop26 2021 pledge to halt and reverse deforestation by 2030, progress is uneven, with some countries like Brazil, Colombia, and Indonesia making headway.

Tom Crowther from ETH Zurich highlights the significant role of local communities, Indigenous groups, farmers, and foresters in promoting biodiversity through various methods like agroforestry, rewilding, and creating habitat corridors. He acknowledges the overzealous messaging in a previous 2019 paper on forest potential for climate mitigation, which sparked debate and led to misinterpretations about the role of tree planting as an alternative to reducing emissions.

Simon Lewis, a critic of the 2019 paper, commends the new study’s more reasonable and conservative estimates. He emphasizes the need for clear understanding and realistic expectations regarding the capabilities of trees in sequestering carbon. According to Lewis, while trees play a role, the primary focus should be on slashing fossil fuel emissions, ending deforestation, and restoring ecosystems to align with the Paris agreement.

https://www.theguardian.com/environment/2023/nov/13/conserving-restoring-forests-sequester-carbon-study-trees