Boy Scouts always have upheld a “leave no trace” ethic on backcountry campouts. With the completion of the Sustainability Treehouse—a living, breathing, self-sufficient paragon of biomimicry nestled within the Appalachian Mountains of West Virginia—the Boy Scouts of America as an organization is exemplifying the ethic of leaving the world a better place.
Rising 125 feet alongside a second-growth forest of oak, hemlock, and hickory in the Summit Bechtel National Scout Reserve, the Treehouse looks like something out of a sci-fi movie. But it functions in perfect harmony with the verdant flora surrounding it.
Like a tree, it captures energy from the sun and channels rainwater gently to the forest floor, efficiently circulating both resources through its system in the process of growth and expansion. In this case, it is young minds that are growing and expanding—the environmental ethics embodied in the structure will hopefully help to grow young Scouts’ capacities to make ethical choices over their lifetimes.
Pursuing certification through the Living Building Challenge (LBC), a 6,500-watt photovoltaic array and twin 4,000-watt wind turbines make the Treehouse a net-positive energy producer, while “tippy-cup” rain chains, a 1,000-gallon cistern, composting toilets, and greywater-filtration features make it a self-contained system from a hydrological perspective.
“We were trying to tell the story of the forest,” says Casey Cassias, the principal-in-charge at BNIM, the Treehouse project’s architect of record. “The lower level looks out at the forest floor,” he says, “and on the middle level, the mid-canopy, you’re surrounded by birds and insects.” The top level is a place for studying the upper reaches of the canopy, contemplating the view and, at night, for gazing into the cosmos above. With open-air “classrooms” at each level, a carefully formed narrative is woven throughout the entire structure, with interactive displays demonstrating environmental principles and sustainable technologies: things like a stationary bike tied to a generator and a cross section of a tree that shows the ecological history of the site.
“We designed the Treehouse to provide visitors with tangible lessons of sustainable design that would inform their future actions and leave them with a strong connection to this amazing place,” says project designer Brendan Connolly, a partner at Mithun, which led the design team. Afternoon snacks are even accounted for: the landscape design by Nelson Byrd Woltz features a selection of edible native species.
Treading Lightly on the Land
Though the site is thickly forested today, it was previously cut for lumber and mined for coal. It’s still in the process of reclamation. The Boy Scouts are developing the site as the permanent venue for the Jamboree, an event that convenes 50,000 Scouts from around the world for a two-week celebration every four years, and the Treehouse, built by Swope Construction, is one of the iconic structures envisioned in the master plan. The planning and design process involved collaboration with dozens of companies and consultants but was initiated during a two-week on-site retreat for the five primary members of the project team. The atmosphere of the charette, says Brad Clark, BNIM’s project architect for the Treehouse, was “competitive, but in a positive, collaborative way.”
The schematic plan for the structure was hammered out during late nights peppered with equal amounts of camaraderie and fierce debate, but everyone involved agrees it was the Appalachian forest setting that ultimately directed the design. “Mithun went back in the forest, found a spot with a clearing, and surveyed the area,” Cassias says. They didn’t know it at the time, but the clearing owed its existence to a rock outcrop hidden just beneath the surface, which resisted colonization by the returning forest.
The program proposed by the clients set a high bar for the team, which was further elevated by a mandate to not disturb the forest. The natural clearing gave them a window of opportunity to build on, but it isn’t easy creating a 125-foot tall structure within such tight constraints. “We had to look closely at access to the space in terms of large construction equipment,” Cassias says. Swope carefully planned the construction of the structure based on the crane size required to swing the structure over the treetops and into position. The company also took advantage of the old logging and mining roads to move equipment to and from the site, and these now serve as visitor and service routes. This complex ballet orchestrated by the team in both design and construction was completed with minimal impact to the young forest.
The Details of a Living Building
When he came onto the project, BNIM’s Clark had already helped design one of the first structures in the world to be certified as a Living Building, the Omega Institute’s Center for Sustainable Living in upstate New York. He was familiar with the difficult task of meeting the LBC’s standards with materials that are readily available on the market.
The oak siding on both the interior and exterior walls meets the LBC’s mandate for site-harvested lumber. Black locust for the decking came from a nearby valley, and the FSC-certified pine used for framing is also from the region. According to Clark, these were obvious choices to reduce energy consumption and adverse ecological impacts embodied in the structure.
“Embodied energy also requires thinking about what goes into the building over time,” Clark says. The team achieved nearly 100-percent passive heating and cooling fairly easily, with careful attention to the prevailing winds, internal airflow, and the Treehouse’s orientation to the sun. Avoiding the environmentally unfriendly substances on the LBC’s Red List, however, took serious focus, as these are found in many common building materials and finishes. Fortunately, the building’s naturally rot-resistant white oak and black locust performs fairly well in its raw form and was treated only with an oil derived from rosewood nuts. “The Cor-ten steel megastructure is a weathering steel that develops its own patina over time,” Cassias says, “which never needs any form of cleaning or surface treatment.”
One of the trickiest aspects the designers confronted was lighting. The design channels sunlight into interior spaces, eliminating the need for daytime lighting, but since the upper deck is also a stargazing platform, no “light spillage” could come from the structure at night. But Boy Scouts climb lots of stairs to reach the top deck, and building regulations require those to be lit for safety. Working with lighting consultant David Nelson and Associates the architects designed a discrete LED illumination system that throws light precisely to where it is needed for safety, while preventing it from bouncing up to pollute the view of the night sky. Given the overall low light conditions prevalent on the site, local officials saw the virtues of the proposed solution.
Through their attention to detail and creative collaboration, Mithun, BNIM, Swope, Boy Scouts of America, and other team members have constructed a subtle yet monumental feat of architecture and engineering, as well as sustainability. By engaging the spirit of exploration and the innate connection between nature and the young people who will come here to learn and play, this one-of-a-kind living structure may infuse a generation of adults with the belief that living lightly on the land can be an expression of human strength.