May 21st, 2015

Fundraising for Phase Two of the Westonbirt Project is now complete. Work has begun on the STIHL Treetop Walkway and the Wolfson Tree Management Centre, which will give visitors an exciting new perspective on trees and allow us to better care for the arboretum’s important collection.

Temporary road
Work is underway on the STIHL Treetop Walkway and contractors, Speller Metcalfe, have been creating a temporary stone access track to limit the impact of the construction vehicles. The access track will be used by mini diggers for the foundations, and for dumpers and the crane. Once the walkway is nearing completion they will remove this track and reinstate it with top soil.

Please keep your dog on a lead
During the construction of the Treetop Walkway, an area around the work will be designated as a ‘dogs on-lead zone’ – you’ll find this construction zone marked on the map in the summer edition of the Westonbirt Magazine and in the summer seasonal guide leaflet, which can be picked up from the Welcome Building.

We’d like to say a big thank you to all of our dog-walking visitors for abiding by signs requesting that dogs are put on leads for a short time during their visit, thus making sure the arboretum remains a safe an enjoyable place to visit and work in as we see these exciting changes take place onsite.


Over at the site of the Wolfson Tree Management Centre, the carpenters have used a 500mm x 300mm piece of timber to create the first “king post”, one of five in the new machinery store.


This image shows two members of staff from Westonbirt’s Tree Team looking into the construction site, and what will eventually become their new base at the arboretum. This is where visitors will be able to look through at the new viewing area which will bring them closer to the work we do to care for our trees.


This image shows timber sourced here at Westonbirt and from the Longleat estate laid out as fabrication gets underway on the timber frame.

Sophie Nash, Project Manager

Tree Management Centre and other updates!

April 30th, 2015

Work is currently underway on what will become the new Wolfson Tree Management Centre. The new facility will provide all that Westonbirt’s expert tree team needs to manage the tree collection. There’s also a lot of other work going on as we start the construction of the STIHL Treetop Walkway and continue our programme of boundary restoration.

The timber for the Wolfson Tree Management Centre has been graded to test its structural strength. This is based on a number of factors including the type of timber, the number of knots and where the knots are.

If you’re around Didmarton Grove in Silk Wood next week, you’ll see more timber being milled by Alastair Williams.

Graded timbers

The timber framers have moved some of the graded timbers into the new yard. They have laid these out in position so they can prepare the ends of the timber ready for joints and connections.

Laid out timbers

Elsewhere, Speller Metcalfe have been on site carrying out additional surveys for the STIHL Treetop Walkway. Work is going on behind the scenes to finalise the details ready for fabrication so we can start digging holes for the foundations.

The Walkway legs are being machined as we speak and there will be more to follow on this in the next blog!

You can also expect to see new metal estate fencing going in during May, as we replace the timber post and rail fencing which runs up the hill from Skilling Gate and along the access road towards the Forestry Commission offices. The new fencing will match the traditional estate fencing you see as you drive into the arboretum.

Sophie Nash, Project Manager

Tree of the month: May 2015

April 23rd, 2015

Acer amamiense

What is tree of the month?
Acer amamiense

Why is it tree of the month?
The new foliage flushes beautiful shades of purple. It really is a treat. The new growth is also rather hairy!

Where can I see it?
We have six plants. Three in 2050 glade, two around Savill Glade and one at the south end of Palmer Ride.

Dan Crowley, Dendrologist

> Find the locations of these plants using the Interactive Map

The Wolfson Tree Management Centre: An Update

April 10th, 2015

Work is currently underway on what will become the new Wolfson Tree Management Centre. The new facility will provide all that Westonbirt’s expert tree team needs to manage the tree collection.

We have just moved five 20 metre long pine beams to the new Tree Management centre yard. This timber all came from Westonbirt and was hand hewn from the round to a beam in November.

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The timber was moved from Down Gate to the new yard using a tractor and a trolley and was escorted on its journey.

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Despite the large open space of the new yard it took careful manoeuvring to move the large beam (one of five) into position.

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The beams are kept off the ground by propping them on ‘sticks’. When the beam was lowered into position it was incredible to see how much the timber flexed. At the time I was a little bit panicked by the thought of the timber snapping!

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The first of five beams in position. Carpenter Oak and Woodland, the contractors will start on site on Monday and will be creating the new machinery store using this timber.

Sophie Nash, Project Manager

Tree of the month: April 2015

March 30th, 2015

Acer pycnanthum in autumn

What is tree of the month?
Acer pycnanthum – the Japanese red maple

Why is it tree of the month?
A rarity in the wild and less familiar in cultivation than it’s American counterpart Acer rubrum, it is going to flower for the first time here at Westonbirt!!

Where can I see it?
Close to Loop Walk on the north end of Holford Ride.

Dan Crowley, Dendrologist

Testing! Testing!

March 30th, 2015

Come to Westonbirt on the 8th and 9th of April and you can help us to user test our brand new app!

Westonbirt App visual

We are especially looking for people aged 12-21 who have a smart device (iOS or Android) to take part. The app allows you to create a new arboretum adventure with challenges along the way.

Participants can use the app on one of two specially created trails (one in Silk Wood and one in the Old Arboretum, which is a dog-free zone) and then tell us what they really think in exchange for a hot drink and a crème egg!

Not in the age bracket? Don’t worry; you can still have a go at the app! Look out for the app testing banner and a member of staff as you enter through the Welcome Building, for more information. We’ll help you download the app and get started on your adventure!

We look forward to seeing you there for some tree challenges!

Susanna Byers, Interpretation Support Officer

Stuck between rot and a hard place…

March 16th, 2015

Deciding when to remove old trees is one of the hardest decisions we have to take here at Westonbirt. All of the arboretum’s trees are regularly inspected for safety reasons and we try to strike the balance between allowing old and valuable trees to remain and visitors’ safety.

As trees reach the end of their lives they tend to go into decline (known as senescence) and as managers we try to care for specimens through this process, for example by gradual crown reduction. However, we can only delay, rather than prevent, the inevitable. Sooner or later we have to say goodbye.

The time has sadly come to fell a magnificent giant redwood (Sequoiadendron giganteum) that has graced Main Drive since the Holford family started their arboretum in the mid-nineteenth century, as its health has been in decline for many years. We have taken the difficult decision to remove it following lots of close monitoring and some recent investigations. Although the decline of this specimen is fairly obvious, it can be tricky to get a clear picture as to what is actually happening inside a tree’s trunk.

The external signs of decay

The external signs of decay

To help us in this instance we recently arranged a specialist test on this tree with the Treetronic system, which uses electric current/voltage to investigate the internal properties of the tree. The result of the measurement is a two-dimensional map of the electrical impedance (EI) of the tree. Importantly, each tree species has a typical impedance (water/moisture) distribution, and to properly analyse the EI results, the operator should have a good working knowledge of how the subject tree species grows and how the water/moisture distribution may vary in different seasons.

As suspected, our results indicated a central column of dysfunction/decay, which corroborates the external characteristics. The resulting diagram for this tree revealed a high degree of decay (red areas), which matches the outer visual evidence. Based on past experience, we can assume that the decay also extends into the root plate, which would adversely affect the tree’s stability.

Graphic showing internal decay in red

Graphic showing internal decay in red

On a brighter note, we do have over 50 other giant redwood specimens throughout the arboretum, and we also hope to collect more wild seed later this year from western USA.

Finally, if a reminder were ever needed that our trees do not live forever and that we do need to manage older specimens in particular, then just a short distance away on Loop Walk you can still see the uprooted remains of a large Nootka cypress (Xanthocyparis nootkatensis).

The uprooted remains of a large Nootka cypress

The uprooted remains of a large Nootka cypress

This tree was being monitored closely due to decay in the base, but unfortunately fell during high winds over the Christmas period before we had chance to remove it.

Mark Ballard, Curator

New life and old traditions

March 9th, 2015

The role of the Community Inclusion team is to enable a greater number of people from under-represented groups to experience the arboretum and to connect with trees. Funded by the Heritage Lottery Fund, Community Youth Officer, Karen Price is working with young people so that they can discover, explore and enjoy the arboretum, either as part of an organised group or as individual visitors.

A group of young people around a camp fire

Its been a busy time in the coppice coups at Westonbirt this winter with the Community Coppice Programme. Almost 50 teenagers have now swapped their pristine trainers for green wellie boots and endured rain, and even snow, to bring new life into one of the derelict coppice coups off Willesley Drive.

The Battle of the Bramble is nearing an end with just a few rogue tendrils holding out against the onslaught of loppers that has rained down on them. Hazel, holly, field maple and ash, all of which have been quietly going about their own business of growing for the last 80 years, have been felled and processed into bean poles and faggots, pea sticks and hedge stakes.

Coppicing in Silk Wood

But what may at first glance look like a scene of destruction, is already springing back into life. It seems strange to cut down a tree to help it grow but that is really what coppicing is all about. The arrival of spring will stimulate a vigorous regrowth of multiple stems from the remaining stump, which will quickly flourish into trees again.

Bluebells, orchids and Arum lillies are beginning to poke their heads above ground, and the increase in sunlight now reaching the woodland floor will soon awaken wood anemone, primrose and hopefully violets. More wild flowers means more butterflies and the birds that feed on them and their larvae. And before long, the biodiversity of the once derelict coppice is thriving once more.

And what about the wellie wearing teenagers? They are helping to keep alive centuries-old traditional skills; learning about managing the woods, charcoal burning, carving spoons and making faggots.

Time for contemplation

But they are also taking away a lot more. They have learnt perseverance when lighting a fire in the rain. To take risks to try something new and to manage risk when felling a tree. To work as a team by looking out for each other’s safety and wellbeing and to break down a task between them to make it more manageable. They have learnt to trust themselves with sharp tools and that others have trust in them. And for me, most importantly, they have learnt to explore and discover and be amazed by the world around them.

Karen Price, Community Youth Officer

Tree of the month: March 2015

February 27th, 2015

Illicium simonsii

What is tree of the month?
Illicium simonsii

Why is it tree of the month?
It is a lovely pyramidal shrub with small, pale yellow, fragrant flowers that are worth seeking out for both their look and scent. It usually flowers towards the end of the month, so keep your eyes peeled!

Where can I see it?
It can be found in both the Old Arboretum (close to Main Drive and Savill Glade (tree number 25.0799)) and in Silk Wood (Sand Earth (31.1424)).

Dan Crowley, Dendrologist, Westonbirt, The National Arboretum

>> Visit the Westonbirt Map to search for trees by name or tree number

The Wolfson Tree Management Centre: An Update

February 26th, 2015

The new yard is now complete!

The new yard
This is a photo taken from the new viewing area location where visitors will be able to view the Tree Team at work.

The new yard

This photo shows the completed vehicle wash-down ready for the jet wash and scrubbing brushes! The temporary fencing around the new yard will soon be replaced with a solid timber fence with a viewing section into the yard.

We are about to appoint a contractor including timber framers who will build the large ‘machinery store’ building using the timber from Westonbirt, which was hewn and milled on site. Work will begin in April. See the artists’ impression below showing a 3D model of the timber frame.

Superstructure of Machinery Store_3D Image

Sophie Nash, Project Manager