As we grow up, we learn that trees are good for the environment due to their ability to act as a physical filter trapping dust and absorbing air pollutants, including carbon dioxide from the air.
But what if the longest living species on Earth are not as good as they seem?
Scientists from the Royal Botanic Gardens, Kew (RBG Kew) and Botanic Gardens Conservation International (BGCI) warn that planting wrong trees in the wrong place can be even more harmful to the environment.
According to their report, several tree-planting initiatives launched by authorities and companies to compensate for their carbon footprint do not actually increase carbon capture and can have long-term negative impacts on biodiversity, landscapes and livelihoods.
The research notes one such example in South Africa when the non-native Australian acacias were introduced for dune stabilisation and timber during the 19th and 20th centuries.
Dune stabilisation is a coastal management practice designed to prevent erosion of sand.
However, in that case, the acacias became invasive, spreading widely across vast areas of land, taking over the natural heathlands and grasslands and lowering the water table, according to the study.
It is estimated that the scheme now costs the country the equivalent of millions of pounds every year to clear them.
The scientific team has developed ten ‘golden’ rules that reforestation projects could follow to deliver the biggest benefits.
The rules cover all stages of the process, from selecting the right site and the right species to maximise biodiversity, through to using the forest to generate a sustainable income for local people.
Dr Kate Hardwick, Conservation Partnership Coordinator at RBG Kew and a Lead Author of the paper, said: “When people plant the wrong trees in the wrong place, it can cause considerably more damage than benefits, failing to help people or nature.”
Professor Alexandre Antonelli, Director of Science at RBG Kew and Senior Author of the paper, commented: “Forests are crucial to all life on Earth. They provide a home to 75% of the planet’s plants and animals, they provide us with food, fuels and medicine and are incredibly important for our mental health and wellbeing.
“Our paper doesn’t set out to say that tree planting is wrong, it is a brilliant solution to tackle global warming and protect biodiversity when done correctly and effectively.”