Tree planting only helps if it’s done properly, and monoculture plantations can even hurt native ecosystems, according to Kew report

Planting trees in the wrong places and neglecting what is already growing are just two of the potential pitfalls, according to a new report. Carla Passino reports.

Trees have a key role to play in the fight against climate change, but only if we plant the right ones in the right place. The message comes from the Royal Botanical Gardens at Kew and Botanic Gardens Conservation International (BGCI), which last week called for a moratorium on deforestation and urged policy makers, landowners and investors to change the way in which woodland is restored.

Reforestation is key in the fight against climate change. However, say the Kew scientists, efforts often centre on large-scale, monoculture planting of exotic species that can damage native ecosystems and even soak up less carbon than natural forest.

‘Native plant species are locally adapted and can thrive without continual management, although the rise of some exotic pests is an increasing threat,’ explain Chris Cockel and Kate Hardwick of Kew’s Millennium Seed Bank. ‘Additionally, many other native species rely on native trees for their survival. If only exotic [trees] are planted, native animals (such as invertebrates) are left more vulnerable. As an example, some butterflies rely almost exclusively on one particular species of tree: a classic is the white-letter hairstreak butterfly, which particularly relies on elm.’

Kew and BGCI recommend sticking to 10 rules, which include protecting existing forests, using natural forest regrowth wherever possible and picking species that maximise biodiversity.

“Landowners should take a long-term view, preserving what they have before rushing into new planting”

The ideal tree depends on the characteristics of each individual site, according to Dr Cockel and Dr Hardwick, but it must be ‘a native species, grown from local provenance seed, sourced from a reputable supplier’. However, they note, it’s equally important to identify the right place for planting; this means not only selecting sites that will create habitat buffers or wildlife corridors, but also, crucially, avoiding high-biodiversity areas that are naturally or historically tree-free, such as peat bogs. ‘It is a misconception to think that a healthy terrestrial ecosystem has to include trees.’

In practice, suggests Dr Cockel, landowners should take a long-term view, preserving what they have before rushing into new planting, favouring natural regeneration (preferably sites close to existing woodland) and promoting traditional management techniques, such as coppicing, as well as replacing exotic timber with native species.

It is a view that resonates with the Woodland Trust, which, in the same week, urged landowners to prioritise the protection of old-growth woods. Ancient woodland stores about 77 million tons of carbon, as well as being among the country’s richest wildlife habitats. However, much has been replanted with non-native trees and the rest is under threat from species such as rhododendron, Himalayan balsam and snowberry.

The charity has not only embarked on a £3.6 million restoration programme across more than 1,100 acres, but is also running a series of free events to help landowners do the same on their own land. Find out more at www.woodlandtrust.org.uk/restoration