Building with whole timber -- as opposed to milling it down into 'products' -- has lots of advantages, ranging from increased fire resistance (seems paradoxical but true), low embodied energy and carbon sequestration.
But we're not talking about sourcing this kind of timber from old-growth forests, but from thinner "weed" trees that are crowding out a stand of trees in the forest, or diseased trees which have fallen. To that end, a Wisconsin-based green design firm, Whole Tree Architecture, is building gorgeous whole-tree structures from these so-called "managed forest thinnings."
Whole Tree Architecture is headed by forester-architect Roald Gundersen, who has made a 16-year career out of working with these whole trees that are pruned as part of better forest management. Says Gundersen in the NYT:
It's eminently more frugal and sustainable than milling trees. These are weed trees, so when you take them out, you improve the forest stand and get a building out of it. You haven't stripped an entire hillside out west to build it, or used a lot of oil to transport the lumber.
The process behind Whole Tree Architecture's beautiful designs start with a "walk [in the] forest with a building design in mind and select individual trees to harvest." The trees selected are 10 inches or less and are chosen often right on the owner's site, and peeled and cured as they stand:
By using local resources, we are able to walk a forest with a building design in mind and select individual trees to harvest. Each tree is chosen both for its structural and design integrity AND for the effect that its removal will have on the forest left standing around it. Often the selection will be based as much on thinning an overcrowded stand or managing an invasive species as it will on that tree being the nearest with a 10 inch diameter trunk.
So, instead of clear-cutting we pick and choose. When the tree has been chosen we peel the bark from it while it stands in the forest (allowing the waste products to go back to the forest floor). Then we leave the tree to cure standing for several months, during which time it will loose up to 50 percent of its weight in water, making it easier and safer for us to move it out of the forest when we are ready.
According to WTA, whole trees selected in this way have a similar weight to strength ratio in compression and twice the strength of steel in tension. Whole trees are stronger than milled lumber because milling "violates a tree's concentric, continuous and spiraling fibers removing the strongest outer layers of the tree, which are naturally pre-tensioned to resist wind shear." Whole timber supports 50 percent more weight than than the largest piece of lumber milled from the same tree.
Besides the structural strength of these components, the integrity and form of the whole trees lends an organic and harmonious aesthetic that cannot be achieved with conventional materials.
It's a kind of integrative building that not only manifests our interdependency on forest ecosystems, but more importantly, also speaks to our imagination.
To see more of Whole Tree Architecture's amazing projects, see their website.
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