Forest loss is a major contributor to climate change, with the planet losing around 420 million hectares of forest since 1990. This loss is largely due to deforestation for agricultural expansion, resulting in 20% of global greenhouse gas (GHG) emissions each year.
Reforestation, the intentional restoration of forest cover, is a crucial tool in mitigating climate change.
"Restoring forests not only reduces emissions directly, but it also helps moderate excess greenhouse gases in the atmosphere by drawing down carbon into biomass," says Lindsay F.
Banin, a statistical ecologist at the UK Centre for Ecology & Hydrology. Forests play a vital role in carbon storage, with trees pulling carbon from the atmosphere as they grow and storing it in wood and plant matter.
Reforestation efforts have numerous benefits, including supporting biodiversity, regulating local and regional climates, and protecting coastal communities from increased storms.
However, a 2017 study found that 9 out of 23 mangrove planting initiatives in Sri Lanka had no surviving planted trees, highlighting the importance of understanding how to ensure positive reforestation outcomes.
A recent study published in Philosophical Transactions of the Royal Society B: Biological Sciences analyzed 176 restoration sites in tropical and sub-tropical Asia to assess tree survival and growth.
The average mortality of planted saplings was 18% in the first year and 44% after 5 years. The study found that the habitat condition at the planting site and the proximity to mature trees significantly impacted survival rates. Larger seedlings and active restoration also showed to positively impact early survival.
While the study provides valuable insights, it's important to note that not every site will have the same outcomes. Variation in outcomes can be due to factors like soil conditions, droughts, competing plant species, and restoration practices. Further research is needed to identify common barriers and challenges to successful reforestation efforts.
"Reforestation has the potential to be successful, but we must address common barriers and challenges to ensure positive outcomes," says Banin. With the right approach, we can bring back the forests and mitigate the impacts of climate change.