February 12th, 2016

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.

The Machinery Store

Machinery store
We have the keys! The first of the three building projects for Phase Two is now complete and the tree team have started to move in.

Machinery store  polycarbonate wall
The polycarbonate wall allows lots of natural light into the building, just inside is the tree team’s workshop where they will maintain their vehicles and will keep their tools. The storage units and pressure washer are now in place ready for use.

Machinery store - interior
The vehicle doors let lots of daylight into the space. We installed several doors so they can drive all the way through the building to access Silk Wood and the Old Arboretum without having to reverse out of the building. This will mean there will no longer be a need to unclip the wood chipper and trailers each morning and evening, so the team can spend more time out in the tree collection.

Machinery store - interior
Now even with some vehicles inside it (these vans belong to the electricians, but will be replaced with tractors once the team are in!) the building is really starting to look like a machinery store. The timber frame still stands out even with the lighting and equipment inside the building. It’s a great large open plan space using arboretum timber, hopefully an upgrade compared to the tree team’s existing tractor shed and mess cabin.

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The Mess Building

On a daily basis the new mess building is changing quicker than we can blog!

Mess building
The entire building has been clad in oak which was felled as part of the management of the coppice coups in Silk Wood; we couldn’t have used more locally sourced timber! Up close each piece of cladding is slightly different and you can see the patterns in the oak. The new machinery store is just visible behind the mess building. The box on the end of the building is a bat feeding perch, much more in keeping than an off-the-shelf bat box.

View from staff car park
The tree team’s new kitchen is on the right of this picture. A deck area has been created and is currently being used by the contractors. When the summer comes other staff and volunteers can join the tree team for lunch.
Now the scaffolding is down you can clearly see the shape of the building and how it fits with the machinery store behind it. The two buildings have been designed to complement each other; the roof of the Mess Building allows more winter sun into the yard behind. The Mess Building also has horizontal cladding and a curved roof which took inspiration from the Welcome Building.

Mess building - polycarbonate wall
The end elevation of the Mess Building has been clad with polycarbonate which matches the new machinery store. This allows more natural light into the building as this end will be used by the tree team as communal space for breaks and a space for meetings.

Inside the building the kitchen is almost complete and the ceiling is being finished. More pictures of the interior will follow in the next blog!

Many thanks to our fantastic team of volunteers who have helped the contractors with the Mess Building.

Tree of the month: February 2016

February 2nd, 2016

Picea brachytyla

What is tree of the month?

Picea brachytyla – Sargent spruce.

Why is it tree of the month?

Hailing from the high mountains of Asia, Sargent spruce is among the most attractive members of the genus. The two bright white, coalescing stomatal bands on the undersides of the needles are a stand out character. Named after Charles Sprague Sargent, former director of the Arnold Arboretum, Massachusetts, USA, it was first introduced by the Gloucestershire born Ernest Wilson. Relatively common in botanic gardens, the species is listed as Vulnerable on the IUCN red list.

Where can I find it?

Fine, large specimens can be seen on Morley Ride in the Old Arboretum and in Sand Earth, Silk Wood. Younger examples can be found close to Loop Walk in the Old Arboretum and along Willesley Drive (var. complanata) in Silk Wood.

Dan Crowley, Dendrologist

Baby giant

February 2nd, 2016

One of the first plantings of 2016, this young Giant Redwood (Sequoiadendron giganteum) was planted on the downs area of Westonbirt. It is the first Giant Redwood of Westonbirt origin to be successfully germinated and grown on site.

Cairn Hurst with a Giant Redwood.

With a success rate of around 25% for seed collected from Redwoods in their native habitat of California, getting home-grown seed to germinate was never going to be an easy task. Keen to give it a go anyway in late autumn 2013 I gathered a handful of cones from the Old Arboretum and decided the best approach would be to replicate conditions found in the wild.

Looking to mimic a forest fire (Giant Redwoods in the wild are protected from fire by their thick insulating bark) I gathered a small pile of redwood twigs to which I set fire. I then placed several cones and some loose seed on a sheet of perforated tinfoil and held it over the fire for a couple of minutes, taking care not to turn the seed to charcoal!

The smoke, as well as heat from the fire, is thought to play a part in breaking seed dormancy. Both loose seed and seeds from the cones were collected and placed in a container in the fridge for a month, a process known as cold stratification; whereby winter conditions are replicated in order to break seed dormancy.

After the month had passed I met with Westonbirt’s propagator Penny Jones to pot up the seed and give them the best possible start in life. We filled two pots with seed compost and scattered the seed evenly on the surface. A fine covering of washed grit was added to help reduce moisture loss while letting the soil breathe. We watered both pots, moved them to the greenhouse and crossed our fingers in the hope that in a couple of months a few young Redwoods would appear.

A couple of months later only one seedling had germinated. One seedling from some two or three hundred seeds! During the following two years Penny expertly looked after the little tree, potting it up a few times and moving it from the greenhouse to the polytunnel to the shade house, where it slowly acclimatized to the weather outdoors and grew at an astonishing rate.

On Tuesday 12 January 2016 Ken Waite and I planted the young Redwood on the downs area near the Welcome Building. It has grown over two feet in two years; hopefully it will grow at the same rate for many years to come and become a welcoming figure for everyone visiting Westonbirt.

Cairn Hurst, Arborist, Westonbirt Tree Team

Arborist Cairn Hurst successfully germinated Giant Redwood seed by replicating the forest fire conditions of their…

Posted by Westonbirt Arboretum on Tuesday, 2 February 2016

The end of a big black pine…

January 27th, 2016

You may notice some temporary traffic lights outside the arboretum today and tomorrow (27 and 28 January 2016).

We have arranged for this traffic management to be put in place as we need to work above part of the A433 road that runs along our boundary.

The work at height in question is the removal of a black pine (Pinus nigra), specimen number 02-0226 to be specific.

We have been monitoring this particular tree for several reasons and over many years, as part of our tree safety management programme.

The tree is within zone one, which is an area with a high ‘target value’, such as places with high public use, paths and rides, adjacent to buildings, visitor centres, car parks, or as in this case near a public road.

The decision to remove any tree is one that is never taken lightly, and an assessment of risk is always based on the following:

  • The identification of hazards that pose a significant risk – defects or factors that could result in failure and have the potential to cause harm
  • Quantifying the risk associated with the hazards identified should be estimated by considering the following factors:
    • The probability of tree failure depending on the severity of the hazards identified;
    • The likely consequence of tree failure, which will depend largely on the dimensions of the overall tree or the particular limbs identified as hazards;
    • The occupancy of the site or level of use – proximity and business of paths etc.

This is an old black pine that has graced the Old Arboretum opposite the school gates since it was planted by the Holford family.

However, it is now in poor condition with some physical defects:

  • It has a major lean and over-hangs a main road;
  • There are early signs of root plate instability;
  • It is multi-stemmed and has been supported with cable bracing in the past which requires frequent inspection.

Due to this combination of factors, we have judged that it has now reached the end of the line and needs to be removed.

We are fortunate enough to have a highly skilled team of arborists at Westonbirt who are undertaking this tree work in a safe and efficient manner.

On a positive note and as always, this very same team will look to plant a young specimen when the ground settles here in due course.

Mark Ballard, Curator

STIHL Treetop Walkway: an update

January 26th, 2016

I’m really excited to see that the timber decking is now in place along the entire length of the walkway! It’s a fantastic milestone to reach, and means we can now move on to the final stages of construction, including the handrail and interpretation.

the start of the walkway from the Welcome Building end
This is the start of the walkway from the Welcome Building end. The new entrance sign is in place and the first part of the interpretation is in position showing the diameter of the largest tree by volume, General Sherman (a giant sequoia (Sequoiadendron giganteum) tree located in California, USA), and the names of all the donors who have funded Phase Two of the Westonbirt Project. The top of the timber bench which will be placed in this area should also arrive this week.

one of the views from the walkway at almost the highest point
This is one of the views from the walkway at almost the highest point at the edge of Silk Wood.

the view looking along the walkway
This photo shows the view looking along the walkway. You can just about see the access to the rope bridge and walk-around feature. You will be right in the canopy at this point with several yew trees, oaks and sycamores either side of the walkway.

the walk-around feature
This is the walk-around feature which will eventually include a swinging rope bridge and a separate platform with several “totems” representing the different layers of a tree.

timber boards
The rope bridge’s handrail and side mesh is in; the next task will be to install the timber boards so visitors can walk across to the platform, and the installation of the platform deck and handrail.

a real sense of the curves is only fully apparent when stood on the walkway itself
Despite seeing the walkway on several plans, 3D models and from the ground a real sense of the curves is only fully apparent when stood on the walkway itself. This photo is taken as you cross Willesley Drive, with the crow’s nest feature on the right.

The staircase up to the crow’s nest
The staircase up to the crow’s nest is steep and has been designed with a bounce! As you can see in the picture this staircase takes you up to a black pine. Don’t worry the staircase isn’t finished! The contractors will be installing timber stair treads and will fit a poem to the stair once complete. Once at the top of the stairs you can peer through telescopes so you can become a nature detective.

Large boulders
Some of you may have noticed some large stone boulders. We have placed these around the bases of some of the walkway legs to protect the walkway from vehicles. The contractors will be installing the last of the boulders next week to protect the legs alongside Willesley Drive.

solid larch handrail
On top of the steel balustrade the contractors will install a solid larch handrail; it is bespoke, chunky and is rarely straight! Some of the interpretation fits to the handrail, including a game at the end of the walkway, so we need it to be in place before the interpretation designers arrive to install it.

Although the walkway looks as if it’s ready to walk on, there are a few more elements to install before we can open. No one is more eager to finish the walkway than I am, having been involved in the project for the last six years. But I think you will agree once you’ve experienced the walkway that it will be well worth the wait!

Sophie Nash, Project Manager

STIHL Treetop Walkway: An Update

January 13th, 2016

Work is continuing on the STIHL Treetop Walkway, which will give visitors an exciting new perspective on trees. The walkway is part of phase two of the Westonbirt Project.

Now that the main structure of the Walkway is finished the contractors have moved on to the finishing touches before work begins on the interpretation.

The Scottish larch for the decking has arrived!

Scottish larch decking

Each piece of timber deck has a grip strip to reduce the chance of slipping in the wet or in icy conditions. The timber is thicker than normal decking to ensure it has a longer lifespan, although the timber has also been treated.

Thick timeber decking with grip strips

The contractors have started at the Silk Wood end of the Walkway and are making great progress. Each piece has been pre-cut to ensure the exposed timber has been treated but to also reduce waste.

Decking in place on the walkwayDecking in place on the walkway

Work will soon begin on the installation of the handrail, benches and the interpretation.

Sophie Nash, Project Manager

Tree of the month: January 2016

January 12th, 2016

Oriental planeWhat is tree of the month?
Platanus orientalis (oriental plane)

Why is it tree of the month?
A parent of the often seen London plane, Platanus x hispanica (the other being Platanus occidentalis), the oriental plane is attractive in leaf and equally so without, with its patchwork bark exposed and fruit dangling from the branches. Attaining large proportions, it has more of a weeping habit than the hybrid and plants will layer, given the opportunity. In cultivation since the sixteenth century, it is native to southeastern Europe and western Asia.

Where can I find it?
Significant specimens can be found in the Old Arboretum on Mitchell Drive and Main Drive. Another characterful example can be found in Silk Wood on Willesley Drive close to the junction with Green Lane. Younger plants are also dotted around the collection, including known wild origin specimens from Cyprus, Lebanon and Turkey.

Dan Crowley, Dendrologist

All go at the Tree Management Centre!

December 17th, 2015

The Wolfson Tree Management Centre is a hive of activity at the moment!

The Machinery Store

The external works on the Machinery store are just about complete! The roofers have arrived in force to complete the roof, and as you can see from the pictures it looks great!

We have a clear panel in each of the roof bays that allows a good amount of natural light in, which is complimented by the polycarbonate at the wash down end of the building, which is also complete.

Machinery store

Inside the machinery store

Roof trusses in the machinery store

The last pieces of the cladding are now being tailored around the pedestrian doors and the window, before the contractors move onto fitting the main roller doors as well as an internal plywood wall with a breathable membrane.

The interior plywood walls will help to protect the inside of the building from the elements rather than just relying on the cladding (the roller doors will also help!).

In the New Year we will move on to the task of juggling contractors to fit the building with electrics, plumbing, security and fire equipment, as well as moving pieces of equipment across from the existing Tree Team yard, such as the vehicle ramp and storage sheds. The trick will be to cause minimal disruption to the Tree Team as possible – fingers crossed!

The Mess Room

The Mess Room has come on leaps and bounds since it was last blogged about, largely thanks to the ongoing support of our amazing volunteers!

The roofers have been in and laid the roof membrane (an extremely durable rubber) and this will be finished by a fanned cladding effect that will reassert the striking slope in the roofs design. As you can see from the picture, it is already looking great, so let’s hope for some dry days so they can get more completed!

Mess 1

Mess Room roof

The interior is coming on nicely as well. The electricians have been in and completed their first fix, as have the security alarm contractors, so we will see them all again in the new year to complete their works.

There’s a lot of hard work still to go on both buildings, but as you can see from all the pictures both buildings are certainly heading in the right direction, and dare I say that we can even start to see the finish line!

By Dan Reid, Project Support Officer

STIHL Treetop Walkway: an offshoot emerges!

November 30th, 2015

Work is continuing on the STIHL Treetop Walkway, which will give visitors an exciting new perspective on trees. The walkway is part of phase two of the Westonbirt Project.

At the end of last week, we saw the installation of the ‘walkaround’ offshoot of the main walkway which will eventually include a rope bridge!

It was a tricky element for the contractors – with five legs to put in place and fix to the relatively small steel frame of the circular platform, it was as close to fiddly as building on this scale gets.

The STIHL Treetop Walkway and 'walkaround' offshoot.
A closer shot of the 'walkaround', which will eventually feature a rope bridge.

STIHL Treetop Walkway: family-friendly and accessible to all…

November 27th, 2015

Work is continuing on the STIHL Treetop Walkway, which will give visitors an exciting new perspective on trees. The walkway is part of phase two of the Westonbirt Project.

This week the contractors made great progress and we’re now seeing the walkway approach the Welcome Building.

We’re getting a real sense of the gentle inclines that will make our walkway an experience which is family-friendly and accessible for all.

A stunning aerial shot of the walkway snaking into the trees.The gracefull curves will make the walkway a joy from the ground too!The walkway snakes into the trees.Along the way 'bulges' in the walkway will be home to fascinating interpretation features.It has been designed to be wheelchair, mobility scooter and pushcair friendly.The walkway as it approaches the Welcome Building