As an award-winning green builder, PCL is no stranger to sustainable building practices.  However, when the Wilder Institute/Calgary Zoo challenged the team to build a complex exhibit in the thick of a forest without disturbing surrounding trees or facility operations, PCL’s Special Projects team had to find some particularly innovative solutions.

In partnership with Calgary design-build fabricator F&D Scene Changes, PCL’s Special Projects team constructed an interactive nature-themed play space that offers children of all ages an exciting introduction to the beautiful world of bugs. Opened in 2020 after one year of construction, the project features a 30-foot-tall prefabricated tree trunk connected to three nearby towers through a series of rope bridges. Visitors are immediately immersed in nature as soon as they step inside the interactive play space, as the structures are thoughtfully adorned with various insects, including ladybugs, caterpillars and bees.

Throughout construction, the team implemented an environmental tree protection program that required all work to be completed without disturbing any surrounding trees or vegetation. 

Ahead of construction, the Wilder Institute/Calgary Zoo’s horticulture team performed an environmental survey of the area to assess the state of the trees on site. Trees deemed in poor condition were removed – all other trees were kept in place, and PCL had to design and construct around them.

To protect tree roots, the project team installed rig mats on the site access road, with additional mats available whenever construction equipment was moved. PCL worked with the zoo’s horticulture team and the landscape architect to establish root protection zones. The project team also added plywood protection around all trees within the construction area to shield them from heavy equipment.

“Before we could augur any piles within a root protection zone, the project team hand excavated the first two feet to ensure no tree roots were within the pile location,” says PCL Project Manager Scott Klinger. “If any roots were encountered, they were reviewed with the zoo’s horticulture team. Small roots not critical to the tree were augured through, but essential roots required the pile location to be shifted and the design to be updated accordingly.”

The project team also added a 300-millimetre-deep engineered wood fiber surface throughout to ensure a safe play environment for visitors. To prevent this surface from suffocating the existing tree roots, a ventilation layer and root barrier were added below to prevent trees from growing into the ventilation space.  This gas exchange system helps maintain the existing trees' long-term health.

During construction, the team worked across active zoo areas to install a new power feed and fiber line from the other end of Canadian Wilds without disrupting visitor experience. A traditional approach would have required closing active paths to maintain public safety due to the intensive process of tearing out asphalt, trenching, laying conduit, backfilling and patching asphalt.

Instead, the team utilized directional drilling to complete the task with minimal operational disruptions. By directional drilling, the path was only shut down briefly and the surface remained unchanged, allowing neighboring habitats to remain open to visitors. 

As the construction manager, the project team managed site logistics, health and safety, scheduling, and cost management from conceptual design through construction.   The team put particular emphasis on pre-planning to adhere to the tree protection plan within the naturally forested area – particularly for heavy equipment logistics for piling rigs, concrete trucks, and the numerous crane lifts required to erect the prefabricated structures.

“We were happy to work hand-in-hand with F&D for construction logistics,” Klinger says. “With our industry knowledge, the Special Projects team could jump in to perform exactly what was needed and help deliver a high-quality outcome for our client.”

This project’s success speaks to PCL’s solution-provider mentality, and its eagerness to go above and beyond in adopting sustainable practices for its clients. “Our Special Projects teams love the opportunity to build outdoor spaces that promote healthy living and bring people together,” Klinger says. “It is incredibly rewarding to have incorporated unique interactive and educational elements into this build, and now see kids connect with the world around them and ultimately have fun playing at this outdoor space every day.”