The Woodland Trust report found that trees face a “barrage of coinciding threats from direct loss to more insidious influences such as climate impacts, imported diseases, invasive plants, mammal browsing and air pollutants”.
In their assessment, the trust also argued that: “Not nearly enough is being done to create high quality and resilient native woodlands as part of larger ecological networks; nor to put more individual trees back in the landscape; nor to restore and better manage existing damaged woods”.
In the UK, woodland covers 13.2% (3.2 million ha) of the land surface, which is an increase from 12% cover in 1998. Half of this cover is made up of predominantly native tree species, while the other is non-native, mostly in the form of commercial conifer plantations.
While the UK’s woodland cover “has more than doubled in the last 100 years”, non-native trees account for most of the increase. The trust found that “existing native woodlands are isolated and in poor ecological condition”, with just 7% in a “good” condition.
Clive Anderson, president of the trust, said: “There is some good news to report. There are more woods and trees in the UK today than at any time in the last 100 years. But we remain one of the least wooded countries in Europe. And we keep losing ancient woodland – ecologically our most valuable resource.”
Ancient woodland covers just 2.5% of the UK. Yet, these woodlands are “rich in ancient and veteran trees with approximately 123,000 recorded on the Ancient Tree Inventory so far – and likely hundreds of thousands yet to record”.
Trees outside of woodland, “such as hedgerows, street trees, trees on farms and along rivers” cover just 3.2% of Britain’s land area. The trust said that while “Little comprehensive data is available to show historical trends for trees outside woodland, one study in eastern England showed that of two million individual trees present in 1850, only one million survive today.”
The trust also found that “The biggest current threat to ancient woodlands is from site allocations, which are areas designated by local planning authorities for residential and industrial developments”. They added: “Planning applications for housing, roads, agriculture, utilities and railways pose the next biggest threats. Together, these six threats account for 80% of current woods-under-threat cases.”
While the tree coverage percentage of the UK has increased, wildlife levels have decreased. The trust found that “The widespread loss of ‘trees outside woods’ from the landscape, including treasured ancient trees, have all contributed to wildlife loss.” There has been a 29% decrease in the woodland bird index from its 1970 value, a 41% decline in the woodland butterfly index and the broadleaved woodland and hedges index has declined by 18%.
Trees are at the centre of the UK’s strategy for reaching net zero by 2050. In the 2019 general election, all parties proposed ambitious tree planting pledges for this purpose.
Woodlands in Great Britain hold up to 213 million tonnes of carbon in living trees, and ancient and long-established woodlands hold 36% (77 million tonnes) of this, despite making up just 25% of all woodland.
According to the report, “Ancient woodland carbon stocks are not static and are projected to more than double over the next 100 years as they lock away more carbon, and in so doing help mitigate climate change”.
Climate change impacts can also be mitigated through greater tree coverage, as they reduce the risk of downstream flooding. The trust used a case study in Cumbria to demonstrate this: “500 hectares of native tree planting in upland catchments, combined with restoring damaged peat bogs, made a measurable difference to reducing peak water flow downstream after just eight years”.
While the current status of woodland is somewhat bleak, the trust set out their “recommended priority actions” in the report. Firstly, they advise the urgent need to expand woodland and tree cover.
“We need to at least quadruple the current rate of woodland creation and increase the proportion that comprises native tree and shrub species to help minimise the pace and level of climate change, adapt to its unavoidable impacts and give nature a fighting chance of recovery.”
Within this, “the location and quality of new woodland is the key to success. This means extending existing native woods and connecting patches of semi-natural habitat; wherever possible enabling natural colonisation by trees on suitable open ground; and ensuring targeted creation”. The trust also advises that “when planting trees, saplings should be sourced and grown in the UK and Ireland”.
In combination with this, existing woods and trees should be enhanced, according to the trust. This would involve restoring all damaged ancient woodlands by removing non-native trees and promoting an ecosystem recovery, while also removing invasive species like rhododendron.