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Above the Canopy

Westonbirt Arboretum is home to one of the finest tree collections in the world, carefully nurtured within a Grade I listed historic landscape.

Understanding Westonbirt

When we were asked by the Westonbirt Heritage Partnership in collaboration with the Forestry Commission to give visitors a better, more accessible understanding of the arboretum and its landscape setting, we responded with a 284-metre treetop walkway—the longest structure of its kind in the UK. Our route opens up stunning new perspectives over Silk Wood for the first time.

  • Illustrative walkway plan

    Illustrative walkway plan

  • Concept sketch exploring site relationships

    Concept sketch exploring site relationships

A bird’s eye view

Our design honours the work of three generations of the Holford family, who from the early 1800s created an ecological resource now recognised by Historic England as a Garden of Special Historic Interest.

The 600-acre site hosts 16,000 unique specimens, including a 2,000-year-old lime tree, laid out in woods, rides and glades. Our carefully curated route provides a rich variety of spatial experiences, bird’s-eye views over the arboretum and opportunities for visitors to learn about a traditional working woodland.

We employed parametric modelling to shape the walkway in response to the landscape, defining a new pathway through Westonbirt’s woodlands. The result of our testing and fine-tuning is a fluid, natural form that responds sensitively to the lie of the land.

  • The walkway snakes through and offers new perspectives of Silk Wood

  • Elevated view shows the complementary palette of the Walkway and Welcome Building

  • Silk wood

Suspended up to 13-metres above the valley floor, our hybrid timber and steel walkway takes the sinuous form of a ‘S’ shape, snaking gracefully through the woodland in mid-air in 10.5-metre spans between slender crossed-timber legs of Scottish Douglas Fir made by Dutch mast makers, Ventis and Brasker Masten. At four staging points the walkway widens, providing visitors with space for contemplation among the tree canopies.

Lean structural elegance and sustainability were our driving criteria, along with a crafted timber tactility in keeping with the woodland setting. The walkway’s touch points of handrails and decking are of FSC Scottish Larch while a light and strong steel balustrade minimises the structure’s weight.

  • A palette of steel and timber

    A palette of steel and timber

  • The walkway is suspended 13.5-metres above the valley floor

  • The slender crossed-timber legs of Scottish Douglas Fir were made by a Dutch mast makers, Ventis & Brasker Masten

    The slender crossed-timber legs of Scottish Douglas Fir were made by Dutch mast makers, Ventis and Brasker Masten

Competition model

Engaging new audiences

Since it opened in 2016, the STIHL walkway has far exceeded the Forestry Commission’s own targets for visitors, almost tripling annual numbers at Westonbirt within a period of six months. As a result of the walkway, the Commission also saw a significant uptake of annual membership at the site and has successfully reached out to a new target demographic of young families.

Fully accessible, the walkway is traversable by wheelchairs, trikes, and buggies—so everyone can have the same experience of an ecologically important heritage woodland.

“People have been enjoying the views of Westonbirt from the ground for generations, so the time has come to offer our visitors a new and exciting way to see the arboretum by getting up close and personal with the canopy. This landmark addition transforms the visitor experience with incredible views, which have never been seen before.”

Andrew Smith, Director of Westonbirt, The National Arboretum

  • Typical bay axonometric

  • Interpolation bay

    Interpolation bay

Client Forestry Commission
Location Westonbirt, The National Arboretum, Tetbury
Size 284 m long
Status Completed 2016
Awards RIBA Regional Award 2017, Civic Trust Regional Award 2017, RICS Regional Tourism & Leisure Award 2017, RICS Regional Infrastructure 2017
Darren Barbier
Glenn Howells
Simon Pearson
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