Our vital work at Leigh Woods

Victoria Stanfield (Area Ranger), Carole Burnett (Lead Ranger) and Hilary McGrady (Director General) walking at Leigh Woods, near Bristol. — Rangers monitoring the trees at Leigh Woods | © National Trust Images/James Dobson

As an area of Special Scientific Interest (SSI), Leigh Woods is a vital natural environment that needs caring for. From looking after veteran trees, through combatting ash dieback, to restoring wood pasture, discover the work the National Trust carries out to preserve this ancient site for future generations to enjoy.

Looking after veteran trees

Leigh Woods is home to over 500 veteran trees. These provide vital habitats for local wildlife, particularly fungi, invertebrates and lichen. Both Leigh Woods and nearby Tyntesfield are sites of national significance because of the invertebrates that are associated with these trees. A recent insect survey showed that 36 of their species are nationally rare, vulnerable and endangered, while one – a moth fly, Trichomyia minima – is completely new to science.

How can we look after them?

Veteran trees don't compete well with younger trees, and can often find themselves shaded out, causing them to die. To prevent this from happening, we clear the surrounding vegetation to allow the trees to come into contact with sunlight. We have to do this slowly – over a number of years – as sudden exposure to sunlight can shock or scorch the trees we're trying to protect.

Another issue with veteran trees is that they can become too top-heavy and split apart. We can prevent this from happening by undertaking specialist tree surgery to remove the branches that are causing the problems. We avoid removing deadwood and fallen branches from around the trees, because rotting dead wood replenishes nutrients in the soil that are needed by the trees and the woodland in general, as well as providing vital habitats for rare invertebrates.

We can also prevent the bark of the trees from becoming damaged by not climbing them or building dens against them.

A volunteer and ranger at Leigh Woods, Bristol | © National Trust Images / Nicole Daw

Combatting ash dieback

We're doing our best to control ash dieback in Leigh Woods, but it’s a tricky disease to manage.

What is ash dieback?

Ash dieback is caused by a fungus that originated in Asia. It doesn’t affect ash trees native to the region, but has had a devastating effect on European ash trees, which are found in the UK.

The fungus produces small, fruiting bodies between July and October. The spores can blow many miles away, and once they've landed the fungus grows inside the tree and blocks its water systems, causing the tree to die.

What does ash dieback look like?

As the name suggests, the disease causes trees to ‘die back’ – they begin to slowly drop limbs, which starts with the leaves wilting and falling. Dark brown spots then develop where the branches meet the trunk, and, eventually, the branches will drop, beginning at the top.

Unfortunately, there’s no cure, and while rangers are doing as much as they can to prevent the spread, they've had to make the difficult decision to fell trees that present a danger to visitors.

What does this mean for Leigh Woods?

Trees throughout the woods are infected, but the initial work will focus on those nearest the paths. Local arborist Sam Harris is helping to remove these trees, so you may find certain areas of the woods closed when you visit.

The trees will be missed, but since they can damage the delicate archaeology beneath them, we're hopeful that there will be some benefit to their felling.

How you can help prevent ash dieback

Cross-contamination across woodland can speed the spread of ash dieback and other plant diseases. You can help stop the spread by cleaning your shoes before and after visiting any woodland, and not taking any natural material home with you.

Rangers and cattle at Leigh Woods, Bristol — Rangers manage the cattle at Leigh Woods | © National Trust Images / Anna Kilcooley

Restoring wood pasture

At certain times of the year, the southern part of Leigh Woods is home to a small group of North Devon cattle whose grazing helps us to restore the more open conditions of wood pasture.

What is wood pasture?

Wood pasture is a form of land management in which open areas of grassland are interspersed with trees and scrub. Although there are only small areas of wood pasture remaining at Leigh Woods, these areas of herb-rich limestone grassland are important as they support rare and scarce plants.

How the cattle are helping

To help us restore the more open conditions of wood pasture, grazing was re-introduced to Leigh Woods in 2009, thanks to funding from a Higher Level Stewardship agreement with Natural England.

The return of grazing animals helps reduce the amount of time rangers need to spend on clearing brambles and scrubby growth. The restoration of the wood pasture also helps to protect the Stokeleigh Camp hillfort by removing selected trees and patches of scrub that are damaging underground archaeological remains.