By David Beamish

Destruction of rain forests has been widely criticised for its adverse effect on global warming, and planting trees has been advocated as a means of taking up carbon dioxide from the atmosphere. So can we help by planting more trees in our gardens?

The short answer is “yes”, but the impact should not be exaggerated. A mature tree absorbs some 22 kilograms of carbon dioxide from the atmosphere each year, some 4 per cent of the emissions per passenger taking a return flight to Berlin. So anyone wishing to contribute effectively to countering climate change should also look at other ways of reducing their carbon footprint. The website www.togetheronclimate.co.uk, run by local resident Jeremy Brackpool, has many suggestions as to how one can be a force for good.

If you are in a position to plant one or more trees in your garden, then the types that are most effective in absorbing carbon dioxide are broadleaved (rather than coniferous) species, ideally fast - growing long - lived native species with large leaves and a broad canopy. If you have enough space, then English oaks (Quercus robur) are particularly effective, as are American sweetgums (Liquidambar styraciflua). The London Wildlife Trust has helpful advice on its website at www.wildlondon.org.uk/actions/how - plant - tree. The oak tree pictured here, possibly as much as 500 years old, is believed to be the oldest in Dulwich Park.

Planting such trees brings other benefits, such as improving soil quality, reducing flooding, and supporting wildlife. Suitably sited trees can also save energy by providing buildings with shade in the summer and protection from cold winds in the winter.

As well as planting trees oneself, one can support schemes for much wider planting. Trees for Cities (www.treesforcities.org) is a UK charity set up to plant trees in cities. The Woodland Trust (www.woodlandtrust.org.uk) hopes to increase UK woodland cover from its current 13 per cent of land area to 19 per cent by 2050 to tackle the biodiversity and climate crises.

Local authorities are also contributing by planting both additional trees and replacements for those that have become unsafe or diseased. In Dulwich, Southwark Council has a programme for replacing street and park trees, and newly planted ones can usually be identified by their support posts and fencing and Treegator® watering bags. Likewise, the London Wildlife Trust plants trees in areas which it manages, such as Sydenham Hill Wood, as does the Dulwich Estate, which planted 100 new trees in 2021 and now seeks to decarbonise where possible, maximising alternative green energy sources and doing more with natural assets - planting, rewilding and supporting natural habitats. In April the Dulwich Society planted in the grounds of Dulwich Picture Gallery a disease - resistant elm (pictured, right) Ulmus ‘Wanoux’ (VADA) to commemorate the 70 - year reign of HM Queen Elizabeth II.

Studies have suggested that tree planting is most effective in the tropics, where trees grow fastest and thus trap the most carbon dioxide. Global initiatives to plant trees world - wide include the Trillion Trees project (https://trilliontrees.org) established by BirdLife International, the Wildlife Conservation Society and WWF.