Managing 6.3 million trees on our estate, and working with neighbours who own 7 million trees next to the network, keeps the railway safe and operational, and we link up with environmental organisations for best practice and research.
The trees on our land include very old and rare specimens – and there are clear regional differences because of variations in habitat. Ash and oak are the most frequently found near the railway in England and Wales, for example, while birch and willow are most seen in Scotland.
You can see a full breakdown of tree species found near the railway at the bottom of this page.
Our tree census
Leaves falling from trees onto the railway reduce trains’ grip and cause disruption to services, and a single tree can have as many as 50,000 leaves. This all adds up, and it’s one of the reasons we carry out vegetation management. Another is to prevent the danger of trees falling onto the tracks due to age, disease or in windy weather, and to make it safe for Team Orange to work lineside.
We are taking a new approach to planning vegetation management following the completion in March 2017 of our aerial survey of all the trees on and around the network. The new ‘tree census’ database allows us to identify and target specific trees that will eventually cause problems for train passengers, so we can plan our vegetation management more efficiently.
Older, or ‘veteran’, trees are a fixture of the railway landscape. Our job is to make them safe so they don’t affect the running of the railway, as sensitively as possible so that this doesn’t harm the tree.
Many of these trees existed even before the railway. Some are protected by legislation. Veteran trees are important as deadwood habitats for rare fungi, invertebrates, lichen, birds and bats – they have a structural complexity providing many habitat niches that do not exist on younger trees.
During an environmental assessment as part of the Green Transport Corridors Project, the Yorkshire Wildlife Trust identified a veteran willow tree on the Hull to Selby line. It had previously been pruned to remove branches growing towards the line, but the work was affecting its long-term health and safety.
Network Rail experts worked with an independent arboriculturalist and The Tree Council to assess conditions and risk factors so they could agree on an appropriate management plan to save the tree so that it would still be safe. The work carried out as a result means the tree doesn’t pose a threat to the safe operation of the network, and the tree’s health and its long-term stability are maintained.
The tree is now registered on our hazard directory and is identified by on-site signage so its importance is recognised before any future work.
When planning our vegetation management work – whether we’re removing trees or planting new ones away from the railway – our experts look to our charity and governmental partners for advice on best practice.
We liaise with Natural England, Scottish Natural Heritage, Natural Resources Wales, Defra, Tree Council, Woodland Trust, the Wildlife Trusts and Forestry Commission among other organisations.
Ash dieback research
Ash dieback disease threatens 20 per cent of our trees in England and Wales, and 12 per cent in Scotland.
To aid the fight against this disease we are linking up with Woodland Trust, Defra, Forest Research and Cardiff University to help fund research into factors affecting its cause and spread, and offering our tree stock to help with the investigations as part of the research.
As part of our aim to achieve a net positive biodiversity impact with our large infrastructure projects during the period from 2014 to 2019, we undertake a number of tree planting initiatives to help offset any biodiversity lost due to work we’ve carried out.
Thameslink and The Greater West are among the projects where we’ve worked with local Wildlife Trusts and other organisations to plant the most suitable tree species at an appropriate location – away from the railway and where it’s most beneficial to the local environment.
Did you know?
- There are over 10 million trees growing 60 metres either side of the railway, covering 20,000 miles – some of these trees lie beyond our borders but may still affect the railway.
- A mature tree can have between 10,000 and 50,000 leaves and each autumn thousands of tonnes of leaves fall onto railway lines across the country.
- The six types of tree that are most problematic to the running of the railway – due to their size and so the number of leaves that fall – are sycamore, poplar, horse and sweet chestnut, ash and lime
- There were over 470 incidents involving vegetation on the railway between April 2016 and March 2017. This includes fallen trees, branches, overhead line dewirements and leaf mulch.
- The biggest trees on the network are an avenue of coast redwoods (sequoias) either side of the railway near Bradford on Avon station (pictured below). The largest is 32 metres tall and 2.5 metres in diameter. They are likely to date back to when this stretch of railway was built in the 1830s, which would mean they’re some of the oldest coast redwoods in the country.
In the Avon Gorge, on the Portishead line (freight trains only), there are six rare species of whitebeam trees on the cliffs above the River Avon that can’t be found anywhere else (leaves pictured left). They have all evolved within a self-contained ecosystem. We have to manage the whitebeams carefully, working with Natural England to ensure we can keep the rock faces safe while protecting the trees.
Tree species by the railway in England and Wales 2017
Tree species by the railway in Scotland in 2017