Wolfson Tree Management Centre
Westonbirt, UK
With an internationally recognised collection of over 15,000 trees, Westonbirt Arboretum is an important and world-class attraction. The management and care of its trees is critical to its success. The original maintenance facilities were dispersed around the site, leading to a number of issues including equipment being left out to the elements and the need to travel between locations to collect tools.
Challenge
The arboretum tasked our structural engineers with undertaking a new, purpose built tree management centre, all within a tight budget. The project involved the construction of two buildings, one to house and maintain tractors and agricultural equipment and one to provide facilities for staff.
Working closely with the rest of the design team, we needed to demonstrate to the client how using materials from the arboretum’s own collection could result in a sustainable facility that has a unique connection with its surroundings. The larger machine store spans 20 metres, so a key challenge for our team was to develop concepts for the materials needed in the construction. As well as being functional, the smaller of the buildings needed to merge seamlessly with the woodland, creating a graceful structure that alludes to fairytale cabin in the woods.
Solution
The use of timber harvested from the arboretum offers a green solution for the construction; reducing the cost of transporting materials as well as reducing embodied energy when compared to using wood artificially dried off site. While the use of this timber is highly sustainable, splits occur in the wood as it dries, which can cause it to shrink and compromise the capacity of the structure’s connectors. Our team overcame this by reinforcing the timber with fully threaded screws to prevent large splits from forming, minimising the impact on the connectors.
We worked closely with the client to gain an understanding of the routine timber management at Westonbirt, enabling us to adjust plans to incorporate different materials as they become available. To keep to the strict budget, we proposed a king post truss for both buildings. This traditional approach allowed both flexibility and made use of the skilled labour available from the Carpentry Fellowship, who were also providing training for the volunteers working on the project.
Both buildings are highly sustainable, with low material impact and minimal embodied energy. Further contributing to the green design, surface water is drained into a soakaway underneath the machine store yard, minimising the additional impact on existing drainage network.
The work of volunteers was key in the delivery of the project. Over 179 days of volunteer time was used during the construction of the staff building alone. The designs for the buildings were developed with the workforce in mind, ensuring they were simple and easy to construct. The volunteers not only helped to reduce costs, but also made sure that the community were involved with the development.
Value
Now completed, the centre reflects the ethos behind Westonbirt Arboretum. Contributing to the on-going preservation of this important site, the new buildings complement the arboretum’s remarkable environment.
