Climate change has become a huge problem for the world.
It is always said that afforestation is one of the best solutions to this problem. However, two new studies have suggested that planting more trees may harm the environment, instead of benefiting it.
The two studies published in the journal Nature Sustainability found that large-scale tree planting is not a simple solution to climate change.
One of the two researchers said that new forests may not offer the desired financial incentives and reduce biodiversity. It will also have little impact on carbon emissions.
It is believed that trees have enormous potential to soak up and store carbon.
In the face of rising global temperature, many countries have resorted to tree planting campaigns. In the United Kingdom, political parties during last year’s general election promised to plant a large number of trees.
The US President has also thrown his weight behind the Trillion Trees Campaign, which aims to plant one trillion trees.
Apart from this, there is a Bonn Challenge, which aims to bring 150 million hectares of deforested and degraded land into restoration by 2020 and 350 million hectares by 2030.
In the Bonn Challenge, around 80 per cent of the commitments made to date involve planting a limited mix of trees that produce specific products.
The authors of the study closely observed the financial incentives given to private landowners to plant trees. They looked at the example of Chile, where the law incentivised 75 per cent of the costs of planting new forests.
The subsidy was not intended for existing forests, but, owing to lax enforcement and budgetary limitations, some landowners simply took to more profitable new tree plantations, replacing native forests.
The study revealed that the subsidy scheme expanded the area covered by trees, but in turn led to decrease in the area of native forest.
"If policies to incentivise tree plantations are poorly designed or poorly enforced, there is a high risk of not only wasting public money but also releasing more carbon and losing biodiversity," said co-author Prof Eric Lambin, from Stanford University.
On the other hand, the second study examined how much carbon a newly planted forest could absorb.
For this, the researchers looked at northern China, where the government promoted tree plantation in view of climate change and to reduce dust from the Gobi desert.
This research divulged that growing more trees increases the density of organic carbon in carbon poor soils. However, tree plantation decreased this density in carbon-rich soils.
"We hope that people can understand that afforestation practices are not one single thing," said Dr Anping Chen, from Colorado State University and a lead author on the study.