It is difficult to get away from talk of tree planting these days. Everyone is proposing it, which is important progress, because even if we manage to reach zero emissions within years as the science demands, we will still need to suck some of the carbon dioxide we’ve already emitted out of the air.

Planting new forests, or preferably letting them regenerate naturally,
is one of the quickest and cheapest ways to address the climate and ecological crisis. However, ecosystems alone cannot absorb all our carbon emissions, as there simply isn’t enough land. So tree planting must
be done in addition to eliminating our emissions, and must not be used as an excuse to avoid it.

Beyond absorbing carbon, trees also reduce flooding, prevent soil erosion, and provide habitat for wildlife such as insect pollinators and birds. But mature trees generally do this much better than saplings, and creating a forest from scratch isn’t easy. Forests take many decades to mature and reach the same level of diversity and carbon storage as ancient woodland. With this in mind, preventing the destruction of ancient woodlands for development of housing and infrastructure, such as HS2, is a much greater priority than new planting.

Tree planting is still important, but we must do it right, and that means having the right trees in the right places. In the past, forestry policy has focused on industrial monocultures of non-native conifers, but these plantations are virtual deserts for wildlife, and have little of the conservation or amenity value of native broadleaf woodlands.

Instead we should be planting diverse forests of native broadleaved trees if we want to maximise the value of our forests. We also need to consider where to put them, because trees don’t naturally occur everywhere. Our islands have many rich and diverse habitats, such as heaths, grasslands and peat bogs, which are naturally treeless. Afforesting them would be counterproductive, not only destroying valuable wildlife habitat but also potentially releasing carbon already stored in the soil.

Critically, we must make sure that tree planting doesn’t distract effort or resources away from eliminating emissions, or protecting the irreplaceable forests we have, not just in Britain, but around the world.

by DR CHARLIE GARDNER

@CharlieJGardner