Episode 69: In the Spalted Woods

Episode 69: The Murder Podcast

[00:00:00] Introduction to the Podcast

Lauren Grand: From the Oregon State University's Extension Service, you are listening to In the Woods with the Forestry and Natural Resources Program. This podcast brings the forest to listeners by sharing the stories and voices of forest scientists, land managers, and enthusiastic members of the public. Each episode, we will bring you research and science-based information that aims to offer some insight into what we know and are still learning about forest science and management.

Stick around to discover a new topic related to forests on each episode.

Scott Leavengood: So I'm excited , for this episode, today's conversation is sure to be a colorful one, and the pun is intended.

[00:00:45] Meet Dr. Seri Robinson

Scott Leavengood: Today we're welcoming Dr. Seri Robinson. Professor in the Oregon State University College of Forestry's Wood Science and Engineering program. Welcome to the podcast, Seri.

Seri Robinson: Thanks for having me .

Scott Leavengood: let's get started with a quick introduction. You, Seri, you wear a lot of different hats in your professional life. You're a professional wood turner, an author, a science communicator, and it turns out the leading authority in the science of spalting, just to name a few. Clearly you have a broad range of wood centered interests spanning art and science.

[00:01:11] Journey into Wood Science and Spalting

Scott Leavengood: Can you tell us a little bit about the path you took to get to where you are now? What draws you to practice and study art and science in the way that you do?

Seri Robinson: Great question. So my undergraduate degree is actually in art and design in woodworking which is my passion. I've been a woodworker now for 33 years, so my whole life.

And then after art school, I wanted more information about the material. I felt like we were taught a lot of design principles. We didn't get a lot of mechanics, which is weird coming from me because I don't actually really like mechanics as a whole, but fundamental mechanics was really important to me to be a woodworker and a wood turner.

So then I did a master's in a PhD in forest science, which was wood science under a different name.

[00:01:54] The Science Behind Spalting

Seri Robinson: And I got really involved in spalting, spalted wood of course is where fungi , certain types of decay. Fungi can grow through and into wood and digest it, and they leave behind these really bright colors.

And it's been used in art for hundreds and hundreds of years across many different cultures. And it's very popular in wood turning. It remains very popular in wood turning to this day. And I really liked the colors and when I needed something to research for my master's my advisor was like, well, what do you like?

And I brought in a piece of spalted wood and I was like. Looks really, it's really bright. It's really I like the colors. I like what it's doing. He was like, well, what is that? And I was like, I don't know. It's spalting and that's all anyone really knew. It's spalting. It's just, it's spalting. Well, what does that mean?

I don't know. And it turned out no one had really ever sat and defined it either. So that was really fun because I got to define sort of this area of art, give it a real definition. And then I launched into some deep look at the causal fungi and, kind of broadening it out. There had been a little bit of work on zone lines, which are those black lines in wood, but no one had really looked at the pigments.

And so yeah, it's just been a rabbit hole of getting to learn more about a historic art form, getting to use it in my own work as a sculptor. And then it turns out that a lot of that those fungal secretions - when I'm talking to kids, we call it fungus puke. A lot of that, those secretions have a lot of neat artifacts and things that can be done in like optoelectronics, so solar cells and batteries and things like that.

So they have a lot of neat properties that keep me sort of one foot in art, one foot in science.

Scott Leavengood: Oh yeah, no, that's fascinating.

[00:03:23] Art and Science Intersect

Scott Leavengood: Truly the intersection of art and science and the fact that you were able to really blaze trail there on something hadn't been explored much.

Seri Robinson: My favorite part of it being in a science program like wood science is the ability to talk about how.

This whole field of science, this whole field of art, it wouldn't be here without art. And so I think a lot of times scientists get really held up in the, we've gotta take physics and we've gotta take chemistry, and we've gotta take all of these things, but art is the exploration of the unknown as well, just in a slightly different way.

And how many times art can lead to new scientific understandings about things that maybe scientists didn't care about before. 'cause you know, realistically who was gonna go look at fungus puke and be like, I bet we can make a solar cell out of that.

Scott Leavengood: Yeah, exactly. That's a very good point. Not a pathway.

A lot of people would've. Thought of, right? No, no. So it sound, it really, it does sound like there's a lot of directions you could have taken your career.

[00:04:13] Career Path to OSU

Scott Leavengood: What brought you to OSU to work in the wood science department?

Seri Robinson: It was a, just a sort of a chance thing. So I had was still in my postdoc at the University of Toronto and my old advisor at Michigan Tech was gonna retire.

And so they actually built a position for me there, which was gonna be a sort of art sci blend position. And it was really cool and I was really excited for it. And this position came up. And I things hadn't been finalized really at tech yet, and I, on a whim, I applied for it because I had, this is a, I'm in a wood anatomist position, if you can believe that.

I taught wood anatomy, and you have to understand wood anatomy in order to do spalting and wood turning right, because it's all wood anatomy. Understanding how the fungi move through the wood and how they. Affect the structure of the wood affects how you machine the wood and it affects what kinds of colors they'll produce.

So different woods will give you different types of colors from the fungi. So you have to have an inherent understanding of the material. And I really never in my wildest dreams thought I would get this job. I considered myself very underqualified for it. What with art degrees and things like that.

But it sounds like the faculty were really excited about the potential to bring in sort of a new direction into wood anatomy. I mean, who could thinks of art and wood anatomy too, right? But those two things are actually. Really intrinsically tied together, especially with woodworking and wood turning.

Scott Leavengood: Yeah, absolutely. And so

Seri Robinson: it was a great, it was a great opportunity.

Scott Leavengood: Yeah. And we're talking about it like it's a new thing here, but you've been here long enough that you got promoted to full professor this year. Is that right?

Seri Robinson: Yeah, just earlier this year. So this is like, geez, I started here January of 2013.

Okay. So it's been 12 years. 12 years,

Scott Leavengood: okay. 12 years. All right.

[00:05:46] Understanding Spalting and Fungal Decay

Scott Leavengood: Well, it's you've talked a bit about it already, but tell us some more about spalting and fungal decay. What's happening in the wood when it's becoming spalted and what are the pigments made of?

Seri Robinson: What's, I think really we have to start sort of with the concept of spalting.

'cause a lot of people think spalting is the fungi. So it's really important to break out that spalting is the product of the fungi. So if you think about bees, when we talk about honey, we aren't saying bees. You know, if you go to the store to buy honey, you don't buy bees with the hope that they will make honey.

You just buy honey, which is the thing they make. And so spalting is the thing that the fungi make.

Scott Leavengood: Ah, okay.

Seri Robinson: And so that's a really important distinction to have because there are lots and lots of decay, fungi in the world. And not all of them necessarily secrete when they grow. In fact, even the ones that do won't do it without some type of stressor for the most part.

So water's limited or there's too much uv, but a lot of the times it's because there's another fungus and they would like to protect their resources. So fungus A is growing happily on a rotting, you know, they're rotten out a log of maple and in its senses, another fungus. And there's lots of ways it can react.

It can mate. It can avoid or it can put up a wall basically to keep the other fungus at bay. And so, in essence, those secretions are, they're either a, depending upon the type of spalting, a physical or a chemical barrier. That's put into the wood so it's secreted into the wood so that another fungus can't grow on the wood and digest it, because the fungi, they're pretty slow growing.

A lot of 'em comparatively to like a mold, and they need time to digest the cell wall and break it down so they can get at the glucose. So in order to do that, they need to hold the resource for a decent amount of time. And they need weeks, months, years sometimes to do that. So they can't have other competitors coming in and taking their stuff.

So just like humans put fences around our land to keep deer out, or other humans, I suppose, fungi do the same thing. They put up these melon boundaries called zone lines, or they do chemical warfare. The sneakier ones do chemical warfare and they'll just turn a whole lot green or pink, and that color is antifungal and a lot of the times.

That moves ahead of the decay. So you can have brightly colored wood well before decay has really set in, and that's the best place. Now if you have a log that's been sitting in the woods for 10 years, it's gonna be very mushy and there'll be lots of good spalting. And at the trick with spalting is always you want to find the pieces or make the pieces where the fungi have been so busy battling and preparing that they haven't had time to eat.

Because then you have sort of max structural integrity without. With a lot of color, but the longer you kind of let them go and interact, the more the wood gets digested in the end. spalted wood is not structural. It's always gonna be used for decorative arts. That's why it was used in Marketery and in Tarsha historically, and that's why it's used in wood turning today.

It's a decorative, beautiful thing, not a structural thing. No ladders outta spalted wood, no houses, please.

Scott Leavengood: Yeah, very good points there.

[00:08:47] Wood Safety in the Kitchen

Scott Leavengood: You also doing research and writing about wood products in the kitchen, in the context of human health and safety. Does spalted wood come with any unique safety considerations, either for the woodworker or the customer?

Seri Robinson: That's such an interesting question because I ended up in sort of wood safety research because of spalted wood, because so many people were constantly asking about spalted wood toxicity. There's a big urban legend that spalted wood is dangerous because people. Afraid of, they're afraid of fungi, they're afraid of mold, right?

You always hear like, look out for black mold, get black mold in your bathroom and it's gonna come after you and things like that and kill you and your pets or whatever. But fungi are a kingdom, of course, like animals are a kingdom. So the fungi that grow in your bathrooms aren't the ones that grow on wood necessarily, and things like that.

It's a huge kingdom. And so the analogy I always like to give is if you get bitten by a spider, you don't kill your neighbor's dog. And that sounds ridiculous, but that's exactly how ridiculous it sounds to any mycologist. When you say, aren't spalting fungi dangerous? Because black mold is dangerous. Like the kingdom is vast, and so throwing a whole kingdom under the bus because of a few bad actors is pretty rough.

Those spalted wood is completely food safe, user safe, all of those things. We've done lots of testing on it. We failed to kill many zebrafish embryos testing the spalting pigments because you have to remember again. That it's not the fungi that we care about, it's their products. So we're using their products, not the fungi themselves, but even then, most spalting fungi are used in human.

They're either eaten by humans or used in like traditional medicine. So they've been a part of us for a long time.

Scott Leavengood: Yeah. Interesting. So we're talking about kingdoms and fungi battles. This is getting more violent than I thought it might, you know,

Seri Robinson: It's pretty violent. Yeah.

Scott Leavengood: So, what about nons, malted wood?

[00:10:34] Woodworking Safety Tips

Scott Leavengood: I mean, we'll ship subjects here a little bit, but any safety concerns in regards to making using wood products?

Seri Robinson: Yeah.

Scott Leavengood: Don't have fungal decay.

Seri Robinson: The whole wood product safety came because when I was talking about, you're talking about kingdoms and. Wood toxicity and thing, or spalting toxicity and things like that.

I would always say, listen. People are more concerned about the dust from turning spalted wood, I would say but wood dust itself is toxic, so I don't understand why you're concerned about the fungi when it, the base material you're working with causes cancer and that's like really well studied and no one seems to know that.

Much either. But wood dust is a massive human carcinogen, and we've known this for, I don't even know, 30 years at this stage. But it just sort of, it branched into talking more and more about wood anatomy, surprisingly. And wood extractives, which all of course, wood scientists know very well. And talking about different types of wood and how we use them in daily life.

Right. Spalted wood, people were always asking about in the kitchen in particular, 'cause they wanted to make salad bowls or cooking spoons or, cutting boards with a little bit of light spalting, which is fine. And then so the conversation always went well, the spalding's fine but what wood species are you using?

Because you know that not all wood species are food safe. And that was a whole, like the amount of people who were just completely unprepared, I think to think that any species of wood would be different than any other one. Right? It's like the whole wood. Wood is wood.

Scott Leavengood: Wood is wood. So

Seri Robinson: therefore all wood is safe is another one of those wild.

Kingdom, not even kingdom. We're in a much smaller area here. All Dicots must be safe is another wild assumption. Uh, but as we all know, right, there's a big difference between woods Purple Heart, which is purple is a very different wood than balsa. Which is functionally air. And so, you know what makes Purple Heart different than Balsa would.

A lot of it's extractive. So things that the tree makes in order to murder, right? It's all about murder. This entire podcast is about nature and murder.

That's what you should call it, the Murder podcast. And you get a lot of listeners, so trees, of course, as you know, right? Preaching to the choir here.

Trees make their own protective defenses. When they're turning the sapwood into heartwood, they turn their extra sugars over into extractives. And those extractives are meant to kill broadly across many kingdoms, including the animal kingdom, of which we are a part. We're much larger than an insect, but that doesn't mean they don't affect us.

Right? And so that's gone into a lot of talking and publications about like, you know, let's really talk about what's in your wood and what's, what should go in a kitchen, because there's a difference between. What you use for a breadboard, which doesn't really get wet so much, and extractives tend to move pretty well with water.

So if you're just cutting dry foods, you could probably get some sketchier woods versus what you use in a cooking spoon, which goes in boiling water for say, pasta. And then the pasta absorbs the extractives that are in the boiling water as pasta absorbs the water. And then you're physically eating the extractives that are in the wood.

Like that's a really big difference. So you have to really think about the application of the wood. The species.

Scott Leavengood: Oh, very interesting. Yeah. No, these are things I had not really thought about. Well it does. So the backing up a little bit, it sounds like the potential impacts are pretty minor, but should I really throw away all of my favorite tropical wood cooking spoons?

Or can I assume that they're safe because I've never had a reaction to them before? What's the big deal?

Seri Robinson: I get that question a lot. So I had a, an allergist explain this to me once that everyone, if you think about allergies and sensitivities and anaphylaxis and all of those things, they're all related.

Like toxicity is one thing, allergies to the other, but they can blend. So if you think about for every thing that you come in contact with, there's a little cup inside you and everyone's cups are different sizes for different things. Now I have very bad asthma and so I have very tiny cups for basically everything that can be inhaled.

So me smelling cedar once is enough to drop me on the floor. But maybe you, Scott, have worked with Cedar for 20 years and you've been fine. So your Cedar Cup is a lot bigger than my Cedar Cup, but, so everyone has different exposure limits that they can handle, but the point is we all have cups and those cups all have limits.

So the more you work with something and the more you expose your something, the more you're building up your reaction. To it, and you see it a lot if you talk to guys who have worked in cedar shingle mills, for instance, and how they can't be around the smell of cedar at all. They'll have anaphylaxis people who work with walnut long term.

I mean, and long term, I mean maybe 10 years, they start to develop pretty bad reactions to walnut. It's one of those things that depending upon your size of cup. Maybe you're not reacting, but you also have to keep in mind the size of your body compared to maybe the body size of a child and the consent of the people coming over.

So if you have your favorite, I don't know, bloodwood cooking spoon that you've always made pasta with, and you're serving dinner to a three-year-old who has a much smaller body and an unknown, you know, cup size what could the potential effects be there?

Scott Leavengood: Mm-hmm. That's a really good point. Yeah. And just talking about that in general.

My Cedar Cup not having used a dust mask or respirator for far too many years, I suppose that cup is nearing com nearing full. Yeah.

Seri Robinson: There's a lot of cups that are, could be overflown there

Scott Leavengood: in future where your breathing protection there. Right.

Seri Robinson: And your skin protection too. Like make sure that when you're in the shop, you shower.

After because the dust from what you've been working with is on your skin. And your skin produces oils, and those extractives are extracting on your skin and absorbing into you, and that's, that tends to be a pretty big thing too. Your mucus membranes, your nose, your eyes. Getting it on your eyelashes and then getting it inside your eyes.

These are all ways that slowly you accumulate these problems. And some woods are just like generally toxic. There's a lot of tropical woods that are just toxic to touch, toxic to. And just regardless, regardless of the size of your cup, you're gonna have Wow. A reaction. So you have to think about it.

In North America, we don't really have that many problematic species, but woodworkers do love a tropical wood, and there's many a breadboard. With inlays of Purple Heart and Bloodwood and Walnut and Maple all glued up together.

Scott Leavengood: Alright.

Seri Robinson: Yeah. You have to, you know, think about the application, what are you gonna do?

How are you gonna do it?

Scott Leavengood: Yeah. Very helpful.

[00:16:46] Wood Finishes and Cutting Boards

Scott Leavengood: So, while we're at it, are there any other popular wood in the kitchen myths you'd like to address?

Seri Robinson: One of the biggest things I did this last year, last year was talking about wood finishes on cutting boards. And this is one of those, like, I feel like everyone in the wood science department kind of inherently understands this.

It's a concept so basic that it would be in a wood textbook, right? If you put a finish on wood it doesn't absorb water as readily, right? We understand this. This is a concept that we all get, and that's the point of finishes, right? Is to keep. Keep wood from cycling so much with changes in humidity.

But in the kitchen that's a bad thing because wood being hydroscopic and constantly equilibrating it's water means that as a cutting board, if it's unfinished, if you cut raw chicken on it and you wash it, just rinse it with water, it'll pull that bacteria down into the board and the surface remains clean.

And this research, this base cutting board research, has been around for, again, probably 20, 30 years at this point. It's very old and it's very well understood, and there's tons of literature on it. And people still really struggle with understanding that wood as a cutting board or a cooking spoon or in the kitchen should be left unfinished because of those properties which we tease over and over again.

So because people were struggling with it so much, we just did a quick little finish study. So we used mineral oil and we used linseed oil, and we did some unfinished and we used salmonella and listeria and made tiny little cutting boards and then stamped them on agar plates to see like what. Just to show like have a real nice visual representation of how much more bacteria you have with Finn and it was wild.

Unfinished wood is just the best at moving bacteria away, so it's pretty much always clean the surface of unfinished wood and it's pretty much species. Irrelevant. Like they all clean, some clean faster than others. Obviously ring porous woods like Red Oak. Red Oak, clean the fastest, as you could imagine, with those giant open vessels that go all the way through cleaned itself almost immediately.

Which is funny because common knowledge is that Red Oak should be avoided for cutting boards because it's so porous. Most of the common woodworker knowledge is avoid porous woods and definitely never use Red Oak because it's so porous that. You'll get bacteria in the board when in fact that is exactly what you want to happen in the board.

Not on the board. That's right. In the wood. Not on the wood is the name of the game. Yeah. And because someone out there is thinking this while they're listening, they have done tests where they've sliced the boards back open and tried to reis isolate that bacteria and it is dead. It is not REI relatable.

It is gone. And it doesn't matter. Even mineral oil, which is a non hardening finish, doesn't matter. It also prevented absorption of the bacteria, and in fact, there was significantly more bacteria on the linseed oil boards, which was a hardening finish, and so it like blossomed the bacteria.

Scott Leavengood: Interesting. Okay. Yeah, I'm sure that's gonna be really fascinating and maybe counterintuitive to a lot of our listeners here. So for anyone go, there's a bunch of podcasts

Seri Robinson: on it if people wanna hear because Okay. After I published, I got invited to talk a lot about it. Okay. So there were a lot of strong feelings about.

Wood finishes out there.

Scott Leavengood: Oh yeah, I've heard many.

[00:19:55] Supporting Dr. Robinson's Research

Scott Leavengood: So, for anyone looking to learn more about your research or interested in supporting your lab, where can we direct listeners for more?

Seri Robinson: Sure. The the lab's base site is northern alting.com, just like it sounds. My lab, my research is actually crowdsourced.

So we don't do much in the way of granting most of our funding comes from the global woodworking community. Interesting. Who's very invested in learning more about the materials they work with and how wood can be functionally used. Right? Historical spalting or wood in the kitchen. And that's done using Patreon, which if you're unfamiliar, is a.

Sort of like month to month sort of crowdfunding place. Right. And so it's Patreon, P-A-T-R-E-O n.com/spalting. And you can subscribe there just to like the lab newsletter and get the updates. Or you can, you know, pop some money over to the lab and, you know, feed a grad student.

Scott Leavengood: They get hungry. Yeah,

Seri Robinson: they do.

Oh, it's crazy like that.

Scott Leavengood: And I'm sure people can just go to like Google Scholar as well. Look up your name.

Seri Robinson: Oh yeah. I'm all over Google Scholar. If you put in Robinson and spalting, you'll keep yourself busy for days.

Scott Leavengood: Perfect. Well, thanks much.

[00:21:02] Lightning Round Questions

Scott Leavengood: Before we wrap up this episode, I have a few more questions for you in what we call the lightning round of in the woods

podcast.

Scott Leavengood: Now, the first question is always, what is your favorite tree species?

Seri Robinson: My favorite tree species is sugar maple. So it's, or sacrum because it's a dense wood, right? Dense white wood. So you, but you get, uh, maple syrup from it, but also it gets figured like crazy. You can have bird's eye maple.

You can have curly maple. A lot of the maple figures happen predominantly in hard maple. So I love that it can distort and get the great different Chito instances , but still be really easy to work with. It Spalts great too, and it tastes great. It's a tree for every man.

Scott Leavengood: Perfect. What's a unique tool that you use that helps you with your work?

Seri Robinson: A unique tool that I use. I mean, my favorite tool, I dunno if it's unique, it's unique to me, is a three eights bull gouge. That is my favorite wood turning tool. Three eights flat topped bull gouge.

Scott Leavengood: All right. Late

Seri Robinson: for turning spalted wood.

Scott Leavengood: Uh, wood turners will know exactly what that means. The rest will have to go look it up probably.

Right?

Seri Robinson: Yeah.

Scott Leavengood: I think you've already answered the third. The question is, what are the resources can you share for our listeners that would like to learn more about your research? I think you've listed those already. Any others? Yeah. Okay.

Seri Robinson: There's lots of books, so I've written a couple books on spalting too.

And Living with Wood is one about like functional wood anatomy in the home. So there's some, if you're not a web person, there are books.

Scott Leavengood: All right. So, well, Dr. Robinson, thank you so much for spending some time with me today for sharing your knowledge with our listeners.

Seri Robinson: Thanks so much for having me.

This was a lot of fun.

Scott Leavengood: Absolutely. I learned a ton here.

[00:22:43] Conclusion and Credits

Scott Leavengood: And this, well, this concludes another episode of the OSU Forestry and Natural Resource Extensions in the Woods Podcast series. Thanks for listening. Don't forget to subscribe.

Lauren Grand: The In The Woods Podcast is produced by Lauren Grand, Jacob Putney, and Scott Leavengood who are all members of the Oregon State University Forestry and Natural Resources Extension team. Other members of the team who've been involved in the podcast include Carrie Berger, Jason O'Brien and Steven Fitzgerald episodes are edited and produced by Carrie Cantrell.

Music for In the Woods was composed by Jeffrey Heino and graphic design was created by Christina Friedhauf. funding for in the Woods is provided by Oregon State University Forestry Natural Resources Extension, the Oregon Forest Resources Institute and the USDA Renewable Resources Extension Act funding.

We hope you enjoyed the episode and we can't wait to talk to you again next month. Until then, what's in your woods?