Cottonwood Canyon Experience Center is built out of wood nobody wants

Juniper is an invasive species that's tough to work with.

Whenever we write about wood construction and mass timber, we get complaints about deforestation and questions about whether it is really green and sustainable. This building, the Experience Center at Oregon State Park, may well become our poster child, our demonstration of wood done right.

Exterior from distance© Signal Architecture + Research/ Gabe Border

Signal Architecture + Research has built the Cottonwood Canyon out of juniper, which is not your usual “Woodman, spare that tree!” material. In fact, it is described as something else altogether.

An invasive and abundant species in Central Oregon, juniper does not enjoy a fond reputation– the current public and private landowner response has been to cut, pile and burn the trees. Studies show a decreased number of animals, birds and butterflies where juniper propagates. In a dry landscape, water is paramount – and juniper trees steal a lot of it. Juniper growth has also been shown to significantly increase soil erosion. Despite the challenges, Signal and the ​Oregon State Parks Foundation aimed to use as much juniper as possible, to set an example of how beautiful the wood could be and what a resource it could be to the community.

wood detailing© Signal Architecture + Research/ Gabe Border

It's not easy to work with, either.

The wood is prone to movement, driven by the presence of knots, the taper of the grain, and the pitch. The finest timbers are free of heart center (FOHC), have a straight grain, and a limited knot size. As a generally small diameter tree with a propensity for knots and lots of tapering, juniper does not compare well to traditional timbers – it therefore is not structural, clear or quarter sawn.

It is also local, sourced 90 miles away and sawn at a mill 45 miles away. And once they managed to cut it, the resulting building looks lovely and smells like cedar.

Exterior Cottonwood Center© Signal Architecture + Research/ Gabe Border

The architects describe the building as “ranch vernacular” with shaded outdoor space, windbreaks, wood stove hearth, and walkways connecting to camping and cabin sites. It is sited to protect the outdoor meeting areas from the strong winds and summer sun; interior spaces are configured for “maximum adaptability.”

Inside  and outside© Signal Architecture + Research/ Gabe Border

​At the heart of Signal’s practice is a commitment to designing for the specificity of the place. This meant selecting materials that resonated with the texture, history and natural resources of the Canyon, and creating a place that is, intuitively, at home in its context.

Interior  of building© Signal Architecture + Research/ Gabe Border

I wonder if they are on to something bigger here, this idea of using invasive species first in wood construction. TreeHugger's sister site ThoughtCo lists 7 Common Invasive Trees in North America , including paulownia on the east coast, black locust and white poplar. Some of the others are poisonous and probably not a good plan. I don't know which of them could be laid up to make mass timber, but at least nobody could possibly complain about it.

Looking up at roof© Signal Architecture + Research/ Gabe Border

Juniper is an invasive species that's tough to work with.