Naturalist

The real value of our woods

There is something especially peaceful about walking in woods surrounded by trees and I like to think that humans have always enjoyed spending time in woodlands and have had a real affinity with trees beyond their economic value. But it is only relatively recently that we have learnt the real value of trees in helping to mitigate climate change by their ability to remove carbon dioxide from the atmosphere. Trees, especially those which are native to Britain, also provide shelter and food for numerous insects, birds and mammals and even other plants such as mosses and lichens and so are a valuable factor in conserving the biodiversity of our countryside.

Some of us may find it surprising to learn that compared with the rest of Europe the UK has a relatively low tree cover of 13%, the average for Europe being 35%. Countryfile viewers will know of Plant Britain, the initiative to plant 750,000 trees across the country in just two years; you can even record just one new tree in your garden on an interactive map on the Countryfile website which is tracking the progress of the project. There are also many organisations such as the Woodland Trust and the Wildlife Trusts which have supported and promoted tree planting for many years. Most of these young trees will take quite a few years to come to maturity and it will take even more years to establish a thriving wood with its attendant biodiversity. Recent research has revealed that individual trees are connected by an underground fungal network providing vital nutrients and amazingly it is even thought that trees can communicate and ‘warn’ each other about impending danger from pests and diseases. Travelling around West Devon it is difficult to ignore the prevalence and devastating effect of ash dieback which is just one of the diseases that can affect our native trees. And so, although it is very important to promote the planting of new trees we must not forget to value and wherever possible conserve our existing trees and woods. Wistman’s Wood, just north of Two Bridges on Dartmoor is a prime example of an established ancient wood which is also a temperate rain forest, constantly wet underfoot and the air always humid. The trees are gnarled, twisted and stunted and famed for the mosses, liverworts, lichens and polypody ferns that festoon their trunks and branches. Many of these epiphyte species, (plants which grow on other plants but not usually as parasites), such as fleshy lobed liverworts and ‘shrubby’ lichens hanging in unkempt tresses from overhead branches, are unique to wet woodland. This wood is indeed a natural ‘time capsule’ of a previous era, a relic of a mighty forest that once covered Dartmoor and probably most of the South West. Its survival is largely thanks to the steep sides of the gorge through which the River Dart flows and the large boulders that cover the ground which made it inaccessible for human exploitation when the rest of the forest was felled for fuel, mining and agriculture and in more recent years the planting of conifers. This and other woods in steepsided moorland valleys are inaccessible to grazing animals, especially sheep, which roam the open moor, thus allowing plants such as ferns and whortleberries (bilberries) to flourish in the ground flora. Redstart, wood warbler and pied flycatchers favour this type of habitat as well as many butterfly species.

In a recent newspaper article George Monbiot, the writer and environmentalist, describes old trees as ‘keystone structures’ for which there is no substitute and on which many other species depend. He thinks that ‘our tidyminded forestry and treating trees as interchangeable is devastating to wildlife’ and he illustrates his article with our own Wistman’s Wood. But there is a fear that its fragile ecosystem is currently being threatened by an influx of visitors. Let’s hope we can leave a legacy of new woods while conserving our old ones for future generations, so that they can also experience the joy of walking in woods.

Pete Mayston