Sara Robinson is not your typical Oregon State University assistant professor—as the newest member of OSU’s Department of Wood Science and Engineering, she’s also the definition of a pioneer. Anyone who performs spalting—producing a stunning array of colors in wood by directing the specific interactions of living fungi—probably learned under Robinson’s tutelage. Her work “bridges the gap between artists, scientists, designers, architects, and engineers who utilize wood resources.”
Artistically spalted wood products, bleached white with thick, contrasting black lines, and often incorporating a whirling amalgamation of natural blues, greens, yellows, pinks, and even purples, are in high demand; not only are they beautiful, they’re rare. Robinson has spent close to one third of her life studying the interactions of different fungal species in wood. As a world-renowned bio-artist, she focuses specifically on how these fungi produce intricate and often colorful patterns as they reproduce, expand, and ultimately battle for territory with other fungi. Her creations range from highly sought-after hand-turned bowls and containers to wood pens, sculptures, and building materials.
“It started off with just looking at how the black lines—zone lines—are made,” Robinson said. “They happen in nature… If you leave a piece of wood in the forest it will end up looking like that.”
Except that naturally spalted wood found on Mary’s Peak, for example, is mushy and structurally useless. Robinson’s initial research focused on which fungi pair best together, and how much time is required for optimal results.
“It takes a long time for the fungus to take out a lot of the wood. Part of controlling spalting, part of what my research is, is knowing when to stop to get the maximum color change with the minimal degradation of the wood.”
The spalting process is divided into three subsections, each of which results in a different visual effect in the wood.
“There’s the bleaching done by the white rot fungi,” explained Robinson, “there’s the zone lines due to antagonism—and these can be from any fungi, and they don’t have to be black—and then there’s just the straight up pigment, which is usually an extracellular pigment produced by the fungi.”
“Zone lines” are composed of the dark pigment melanin, and are the antagonistic results of competition between different types of white rot fungi. Within their melanin boundaries, which act as barriers against other fungi, white rot fungi break down dark-colored lignin in wood, leaving behind lighter-colored cellulose, and producing a bleached effect.
“This is a giant warzone graveyard, so every time you look at spalted wood, you should think, how many different fungi were on here battling?”
Robinson notes, “You couldn’t use this kind of spalted wood for anything super structural—I wouldn’t make a table out of it. You could with the pigmented wood, because those pigment fungi don’t degrade the structure of the wood.”
Once Robinson has treated wood—of essentially any size and shape—with white rot fungi, she will either treat the wood again with fungi that produce pigments (colors), or she’ll extract pigments out of fungi and then “paint” those pigments into the wood. Painting takes less time than natural processes, and allows her to use pigments from fungi that don’t grow well on wood, or which significantly degrade wood.
The complete spalting process is lengthy (it can take many years), but application of the fungi themselves is simple—it’s mainly a matter of putting the fungi in contact with the wood, however you can. Robinson keeps her spalting wood in plastic bins, and recommends that spalters don’t remove bark, since it helps to retain moisture.
“So often I get students who volunteer in my lab to work, and this is one of the big hurdles I have to jump over with them, because they’ve been taught that everything has to be precise, and happen in a certain way. But this is a biological system, it’s messy,” Robinson laughed.
One of her projects included work with naturally pre-spalted lumber that would otherwise have been considered trash. Fungi carried by mountain pine beetles can spalt wood to be used for building materials, significantly devaluing the product. Instead, Robinson inoculated the wood with a pink-pigmented fungus, and later with one producing a blue pigment, creating swirling purples. Blue- and yellow-pigment fungi produced gorgeous green colors. One of these small boards, previously junk in the lumber industry, is now worth about $20.
Robinson, who began her position at OSU on January 1st of this year, received her undergraduate degree in Woodworking in Art and Design, but felt dissatisfied with what she had learned.
“My whole life I’ve been a woodworker, I grew up replacing windows and roofing,” she explained. “I was really upset when I finished my undergrad degree, because it was all woodworking and no information—they taught us how to work the wood, but they didn’t teach us why.”
So when Maoists took the capital of Nepal, delaying her placement within the Peace Corps, Robinson’s interest in the spalting process landed her in a Master’s Degree program at Michigan Tech. Degree completed, she was finally able to travel abroad, this time to Thailand.
“My papers had been really well received, which I didn’t know since I was gone in a foreign country getting parasites,” Robinson laughed. “I got back and my old advisor convinced me to do a PhD. I should add that I had never planned on going to college, my parents really pushed me in that direction.”
“Previous to me there was nothing,” said Robinson, who has now trained several students in her discipline, and will always welcome more. “We understood what causes zone lines, it’s been looked at by a lot of researchers in the 1970s, but that was in terms of plant mechanisms.”
To keep up with her work, and to learn more about spalting, visit Robinson’s website, www.northernspalting.com. And keep an eye out for her workshops, held 1-3 times per year, which attract participants from all over the world.
by Genevieve Weber