National Tree Week (27 November – 5 December) started in 1973 as a result of Dutch Elm Disease – a tree disease that saw the decimation of the UK elm population. The idea was to get communities to do more to help the trees in their area. Now National Tree Week aims to spread awareness about the vital role trees play in our environment.

It’s widely understood that trees are central to our ecosystem, not only because they absorb carbon dioxide from the atmosphere, helping to limit global warming, but also because of the nutrients they release into the soil, allowing other plants to grow. Many species depend on them. For example, oak trees support 2,300 species – 326 of which are entirely dependent on oak for their survival.

They have other super-powers, too. They are often long-lived, with some yews surviving for over 4,000 years. Old trees are particularly rich in wildlife: one ancient oak has more diversity of life than a thousand 100-year-old oaks. Ancient trees are notably special for their fungi, invertebrates and lichen. They’re not only important when they’re alive: deadwood has important ecological benefits, providing habitats for bugs and beetles, which is why our reserves teams try to leave fallen trees on the ground wherever possible.

Nearly 50 years on from the Dutch Elm Disease crisis, our trees are facing another deadly threat. Confirmed in the UK in 2012, ash dieback is a fungal disease affecting ash trees.  With the spores causing the infection moving large distances on the wind, it is likely that most of Avon’s ash trees have now been exposed. The disease makes it likely that deadwood will fall out of the canopy – or the tree may even fall altogether. 

For Avon Wildlife Trust, this is a significant public safety issue. Trees posing a threat to safety will have to be felled. Reserve visitors are likely to see increasing evidence of tree-felling, especially when visiting sites with a high proportion of both ash trees and public access, such as Browne’s Folly. For news about these impacts, or to learn more about the challenge we are facing in dealing with ash dieback, head to the Trust’s website. 

Happily, we won’t lose all our ash – a minority are showing tolerance to the disease. Not only that, while the loss of ash trees will have a catastrophic effect on some species, sometimes the emerging habitat will be more welcoming to wildlife than what it has replaced. Over time, the loss of ash from the canopy will increase the amount of light in the woodland, creating ‘edge’ habitat such as glades – typically the most biodiverse part of a woodland. This will usher in more flowers. Fruits such as blackberries and hazelnuts will thrive in the newly developing scrub. This will feed and house insects, which will in turn feed bats and birds. What was a simple woodland habitat could, in short, become a vibrant haven for wildlife, alive with colour and abuzz with life.

There’s a lesson here which goes beyond our reaction to ash dieback. Having a healthy tree population is not just about having more trees. It’s about having the right trees in the right place. Ancient and veteran oak trees, often islands teeming with rare wildlife, need space around them to thrive. In fact, wood pasture, where such trees grow in open grazed land, is one of our most valuable habitats. In contrast, dense tree canopy can create very poor habitats, with low biodiversity.

There’s no doubt, getting landscapes right for trees and for nature is complicated. That means getting everyone working together.  Avon Wildlife Trust works closely with other organisations to help our trees. Now we and our partners across the West of England have come up with a tree ‘strategy’, The Forest of Avon Plan. This vision of more, better managed and connected trees and woodland across Avon is already being used to help guide investment and planning decisions, as well as to focus our efforts on the most important areas where we should be helping trees.

Nothing is simple and creating healthy habitats for trees in an ever-changing landscape is no exception. However, sometimes it pays to go back to basics. Trees are beautiful. They feed our soul and clean our planet.  This weekend, why not head outside and take some time to appreciate the autumnal glory of the trees on your doorstep? It truly is a gift we all can enjoy.