Tillamook Forest Center
A Bridge Between Eras: The Tillamook Forest Center tells the story of past human stumbles while embodying a leap into the future
Few places betray humans’ impact on nature so flagrantly as the verdant Tillamook Forest of Oregon’s Coast Range. Loggers stripped the hills of its sturdy old growth trees in the late 19th and early 20th century. Catastrophic fires ravaged the remaining younger forest—not once, but four times between 1933 and 1951. With the mountains seared to a moonscape and the watersheds eroded into silt flows, the Oregon Department of Forestry set about saving the landscape by sending busloads of school children and other do-gooders to plant 72 million trees over the next two decades. The result: a 355,000-acre monoculture of 100-foot-high trees as evenly grown as a golf course fairway.
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With new growth now 50 years old, the Department of Forestry is rediversifying the forest by harvesting trees and introducing plants, while creating campgrounds and trail systems. To showcase the history of the project and the efforts to manage nature more effectively, the department hired Miller Hull Partnership to design the new center.
Miller Hull is no stranger to plum regional architecture-in-nature assignments. But partner-in-charge Bob Hull, FAIA, recalls how his heart sank a little upon seeing the site. “As Northwest architects, we’re used to prismatic places,” he says. “But this was something different. There was hardly any undergrowth and all the trees were the same height.” But thanks to a remarkably fluid collaboration among the architects, environmental engineers, the Department of Forestry, and the lumber companies working the forest, the new center’s architecture and systems quickly grew into a working metaphor for the modern complexities of the working forest. “We quickly realized,” says Hull, “that our job was really to interpret the site.”
The team nearly walked the entirety of what would become the trail system on its first visit, Hull recalls. The sounds of the nearby Wilson River drew them deeper and deeper into the trees as Department of Forestry’s project director Doug Decker described his agency’s plans for trail and campground systems. The resulting 14,500-square-foot center’s parti nearly drew itself: a building that metamorphoses into a bridge. Hull likens it to the “skids” used by old-time logging operations in which cranes and other equipment were raised and leveled above the forest floor with platforms built atop beams made of felled trees. The interpretive center’s two wings (one for exhibits, the other for theater, meeting rooms, administrative offices, and services) occupy two 320-foot-long, gable-roofed boxes that resemble the region’s vernacular barns. A concrete post-and-beam system holds the structure aloft from the river canyon’s steepening grade and then merges with the structural system of the 250-foot-long bridge, which combines a concrete girder middle span bracketed by cable-stays suspending the approaches. A replica of a fire lookout tower stands sentinel over the site.
Constructed out of a smorgasbord of contemporary forest products donated—and in the case of the bridge, engineered and built by Willamette Industries and its eventual purchaser, the Weyerhauser Corporation—the building, bridge, and tower all have a muscular, industrial look befitting the forest’s history and the scheme’s stern geometry. All of the buildings’ framing materials were harvested within 30 miles of the site and most of the rest of the wood came from within 150 miles. Even the steam “donkey” (an early-century hauling device for heavy logs), salvaged from a nearby abandoned logging site and integrated into the building as an exhibit, looks right at home.
But the team’s close, multidisciplinary collaboration blossomed most brightly in the building’s treatment of ground water and energy. With over 110 inches of rain falling in the forest per year, landscape architect Doug Macy, for instance, advocated early in the design process for a pond in the entry sequence. Hull, in turn, suggested filling it with water harvested from the roof. The Department of Forestry then proposed making it big enough to serve pump trucks in the event of a fire on site. Other local fire officials lobbied for further enlargement to fight fires nearby. Mechanical engineer Paul Schwer of PAE Consulting Engineers then realized an even larger pond could serve as a heat sink allowing the building to be cooled in the hot, late summers with water instead of air, resulting in an efficiency increase of 40 percent. The final size: a 65,000-gallon reservoir at the building’s entrance dubbed the “pond of many uses.” Fed by a simple metal scupper connecting the center’s two roofs and suspended by rusted-steel rails salvaged from another logging site, it now serves as an industrial grade rain fountain. “There’s no pretense about it,” says Schwer. “It’s a big honkin’ thing you see when you walk in. When it’s raining, it’s a waterfall, and it even flushes the toilets.”
The team found a similarly direct solution for the building’s air systems. For most days, cooling happens through simple cross-ventilation with operable windows and fans placed at the peak of the roof’s gable ends. The pond-fed water-cooled air conditioning provides a backup only for the hottest days. In the search for a more innovative heating solution than the usual propane systems used for similarly remote sites, they looked to the veritable gold mine of waste: the sawdust pellets produced as a by-product by the forest products industry.
Though pellet stoves are commonly used in homes throughout the region, none had been tried in a public building or on such a large scale. The contractor’s estimates came in high. The Department of Forestry initially feared the risk of an untried system. But when the department’s project manager Frank Evans discovered the center’s energy loop could be tightened to a mere 50 miles, he became the system’s most vocal advocate. Now the three 89-percent efficient boilers heating the center are fed by trucks that deliver corn to the nearby Tillamook Dairy. Empty for their return trip, they now pick up pellets from mills for the twice-yearly feedings of the interpretive center. Courtesy of Hull’s enlargement of the silo to 12 tons to match the industrial heft of the building’s other features— and the use of a transparent feeder tube—the pellet system stands as a signature architectural element, while serving as one of the building’s interpretive exhibits.
For all the seeming simplicity of the systems, the early months of operation were bumpy. A computer mix-up of air sensors had the building heating all the time. The water-cooled air-conditioning worked fine with the pond water, but backup water from a ground well corroded the pipes, necessitating the addition of a reverse-osmosis filtration system that, standing to the side of the buildings like an off-the-shelf backyard storage shed, interrupts the otherwise clean vocabulary of concrete, wood, and galvanized steel. Though the Department of Forestry opted not to pursue LEED certification, Hull estimates it would earn a silver rating. But the project snared one of the State of Oregon’s first State Energy Efficient Design, or SEED Awards, for attaining a 30-percent reduction in energy performance over the state’s already rigorous codes for new construction. The University of Oregon’s Community Guide to Biomass Thermal Projects recently included the center’s near-carbon-neutral pellet-burning heat system as a case study. Courtesy of the Department of Forestry’s pioneering, Schwer says the system is even being used at the recently completed Harney County Hospital in southeastern Oregon.
While Hull laments that the center “disappoints me in photos,” its successes are subtle. The splitting of the truss’ king posts allows a rare integration of fire-sprinkling systems, with the main feed elegantly running down the ceiling’s peak. The board-and-batten ceiling system serves the acoustics beautifully, while giving the interior the feel of a woven basket. Hull’s use of it at the building’s ends welcomes the kind of dappled natural light to the front and rear porches found in a barn or covered bridge. But from the silo to the pond, the center and its systems stand as a rare example of architectural integration that reaches beyond style and materials to its operations. “Architects always want me to hide what I do,” says mechanical engineer Schwer. “But here, it’s part of the scheme.”
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