Engineering Spotlight
Richard Foth
Co-op Connections | July 2008
Today's Environmental Engineers
Richard Foth4th-year Civil Engineering Co-op Student
In 2007 Vancouver was hit by multiple windstorms, which toppled many of the oldest and largest trees in Stanley Park. That November, the Vancouver Parks Board came to David Nairne and Associates Ltd. (DNA) with a challenging design problem.
Due to the significant damage caused by the storms, the public became increasingly interested in how the forests in Stanley Park were managed namely, the removal of fallen timber and preservation of the remaining trees. During this time it was discovered that one of Vancouver’s oldest and most famous natural monuments, the Hollow Tree, was beginning to tip over. The increased pressure of public opinion forced the Vancouver Parks Board to seek expert judgment concerning the structural integrity of the tree.
My role at DNA was to design and draft a number of options to save the tree from falling. The most difficult aspect of design came from the fact that the tree had been dead for nearly a century; it showed significant decay and fragmentation. The most feasible design was to support the tree with a number of angled posts directly in the line that the tree was leaning. The posts would be attached to the tree by a stiff steel collar to ensure that the trunk would not collapse under a new loading method. Other designs that I came up with were too obtrusive to the visual landscape, too expensive, or were not practical for construction. Since the tree had been rotting for nearly a hundred years, structural solutions for the tree would only prevent an immediate collapse and temporarily stabilize the trunk and provide no long-term solution.
In the end, the Vancouver Parks Board concluded that it was in the best interest of public safety and budget to topple the tree and if possible, display the Hollow Tree in its final resting place on the ground. Although the final fate of the tree was removal, my designs were considered for an important decision regarding a historical rescue operation.
