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Jessica: Hi, this is Jessica with Build Green, Live Green CaraGreen’s podcast on sustainable materials and trends in the building industry and today we have John Heyesen with Arbor Wood Co. with us and John, we’re excited to have you. We’re excited to be working with Arbor Wood Co. and you know we’ve known each other through you know some of your prior ventures including Arbor Wood. But you know we’ve always tried to find a way to work together and I’m really excited that Arbor Wood brought us together.

Jon Heyesen: Absolutely yeah, we’re equally excited.

Jessica: Well so you know, I know a little bit about the background of Arbor Wood Co but can you tell our listeners kind of how you ventured into the business and where you guys are today and what’s positioned you to be taking on. You know this larger role here in the thermally thermally modified wood space.

Jon Heyesen: Yeah, absolutely so we run and have run for about a dozen years a architectural material distribution company in Northern Minnesota called Intectural. We’ve curated a line of of sort of sustainably minded building materials and and throughout that journey. And really through a relationship we have with the University Of Minnesota and their natural resources research institute we became hip to this emerging technology coming out of Europe called thermal modification and it made sense for us and and had really good alignment with the rest of our portfolio to. To effectively build a brand and and start to bring thermally modified wood to the US market. We’ve been doing that for about nine years which really puts us somewhat at kind of the vanguard of that movement here in North America. It’s technology that was developed and really commercialized in the mid to late ’90s in Europe and so we’re excited and it’s a good time and we’re we’re definitely seeing the market evolve and grow in front of us and and we’re investing in our business and are kind of on a trajectory to really increase production and do some really neat stuff.

Jessica: So for you know, just for a little bit of background on thermally modified wood. What does that mean because I mean people are familiar with pressure treated, heat treated but thermal modification is you know, it’s very pointed in terms of the durability that it imparts on the wood in the performance increase in the wood. So can you talk a little bit about what thermal modification is, why it’s different than you know, simply just pressure treated wood and what it does to the wood to make it perform better?

Jon Heyesen: Thermal modification is a natural process. It’s a process largely based on just heat and steam. So It truly is a chemical free process and it is all about improving both the biological durability and just the general outdoor stability of wood. And what’s really interesting about thermal modification is that it does work against a lot of different wood species. So it provides some some versatility and some flexibility there. We’re talking both hardwoods and softwoods and some of the science behind it is that the the wood is modified in a high heat, oxygen-deprived environment and that high heat causes a chemical change referred to as hydrolysis. And, so what’s happening is we’re breaking the hydroxyl groups, we’re degrading the hemicellulose in the wood and it’s primarily about moisture abatement and really changing wood’s relationship with water because with water and, the naturally occurring sugars and the nutrients that are contained within water, well, that’s that’s where we have mold and rot and fungal decay. A lot of moisture stored in in the cell walls of of a plant will also lead to dimensional instability, thermal expansion and contraction and so by really fundamentally changing wood’s relationship with water we can improve stability. We can improve durability. And, because there are no chemicals, there’s no preserving agent added to the wood. There’s really nothing to leach out over time. So the wood has fundamentally been changed. Kind of forever at the cellular level and and it’s really effective. It’s really exciting and again it works across a range of species.

Jessica: So if you’re making these changes to wood and you’re talking about increasing the durability, what kind of warranty are you talking about here in terms of number of years that this wood is.

Jon Heyesen: Yeah, so I think a reasonable sort of the the general industry understood life expectancy for thermally modified wood is twenty-five, thirty plus years. What happens after 30 years, I think part of this is that the technology is is roughly thirty years old, so we’re now just starting to see the tail end of some of the initial proofs of concept of this technology but the wood is I think at lay terms a lot of people think about it as being almost petrified. So.

Jessica: Yep.

Jon Heyesen: With with a reasonable amount of care and a little bit of maintenance, there’s no reason to believe that thermally modified wood in an exterior application couldn’t last well beyond 30 years but it’s not a composite. It’s just wood at the end of the day which also means that at the end of its useful life, it can be recycled. It can be repurposed into anything from biofuel to you know mulch for a landscaping bed.

Jessica: Okay, well that that’s great. You kind of alluded to exterior applications. So in terms of applications of of the wood that you make what are some of the profiles of Arbor Wood in terms of planks and what are some of the applications that it’s used for.

Jon Heyesen: The most common applications for for for Arbor Wood and for most manufacturers in the industry would be cladding and decking. It performs very well as an architectural rain screen. The technology allows for a lot of different wood species to perform very well in a decking application. It’s worth mentioning that the modification process does apply a certain amount of stress to the wood and part of the change in the hemicellulose of the wood renders it not quite as as structurally sound so the recommendation is for non-structural applications. So for example, we would not suggest somebody frames their deck in thermally modified wood, in Arbor Wood, but you would you would use Arbor Wood Decking to deck your deck. You can use modified wood for a railing, for a pergola, for sun shades, things of that nature, really non load-bearing structures are absolutely appropriate.

Jessica: No no.

Jon Heyesen: We’re also seeing really interesting industries and interesting use cases evolve kind of every day as people become aware and really tap into some of the attributes of modified wood. For example, luthiers, guitar manufacturers, even stand-up paddleboard manufacturers, ski manufacturers, furniture manufacturers. They’re starting to explore modified wood for its stability for its durability and oftentimes really even just just for the color which is a funny attribute to talk about, But, because we’re cooking wood at a very high temperature, the wood takes on some really beautiful tones that are really baked all the way through the entirety of the mass. So, now you can start to kind of replicate some of the exotic woods that historically would be sourced say from a rainforest but now you can do it with domestically sourced and responsibly harvested woods.

Jessica: That’s a caramelization right? Kind of that’s happening with sugars in the wood?

Jon Heyesen: That’s right, That’s right, Yeah, the sugars are caramelized, is a really great word there you know, we’re sort of roasting the wood and so this, for example, is our thermally modified White Ash when you see this sort of green. It’s very much a blonde just natural wood color. There are no pigments. There are no dyes to sort of get to this really pretty color but this is just what happens as part of the process.

Jessica: Yeah, we we prefer brunettes over blondes, anyway. Cool. Anyway, so outside of the Ash, what are some of the other species that that can be can be thermally modified because I want to talk about chemically modified wood in a minute and I know that they’re relegated to mostly one species.

Jon Heyesen: That’s right. Yeah, so thermal modification does work against softwoods, hardwoods. We have modified perhaps a dozen different wood species. Anything from red oak to white Ash, Aspen, Maple, Basswood, Southern Yellow Pine, Eastern White Pine, and so the the versatility of the technology is part of what was really interesting and compelling to us and for a lot of manufacturers. It allows us to take almost a hyper-local approach to a given project where we can even explore the use of trees that were maybe felled from a construction site and we can take those trees in turn put the value add on it, mill them, and reuse that wood in the construction of whatever that building happens to be.You know, also just thinking about the the supply chain issues, we continue to see sort of globally across all industries and thermal modification allows us to quickly pivot and sort of adapt our product line to potentially wood species that has greater availability or is growing in abundance or if we see certain insect infestation that’s impacting a certain species, say like the Emerald ash borer. Something we’re paying attention to that should that negatively impact and really shut down the availability of Ash where we could flip to something like a red oak. Talking about a lot of the the more natural albeit chemically preserved wood modification techniques like acetylation, like furfurylation, some of the brands would be Accoya, would be Kebony. Those processes are are basically a chemical impregnation process and they really only play with softwoods and that’s why you’ll see radiata pine kind of exclusively as a species used by a lot of those brands. Yeah.

Jessica: Ah, right. So the chemical modification it, in some cases, it kind of swells the wood cells but it does. You know it requires kind of this sort of outside influence and it does have additional equipment used to to create that process but my understanding is that some of the starting material, it may be sourced from, you know a responsibly managed forest or plantation. Um, and I mean plantation in the sense of a lot of trees planted there but they travel a lot. Like, sometimes the wood starts in the Carolinas and ends up going to Europe and then maybe comes back, or New Zealand you know. Is my understanding correct? That it’s a well-traveled species? You know it’s a well-traveled process and species to get this Accoya or Kebony wood?

Jon Heyesen: Yes, yes, and even some of the European manufacturers of thermally modified wood are sourcing their timber from North America, bringing it to Europe for modification and finish bringing it back into the states and so, you know, part of the value proposition of these modified wood technologies is all about building materials that are gentle on the planet and it’s all about reducing the embodied carbon on a given construction project. And when you talk about the carbon the logistics, carbon footprint as part of production, it really kind of starts to shoot some holes in in that value proposition.

Jessica: Right.

Jon Heyesen: And yeah, when we look at the Accoyas, when we look at the Kebonys, some of those techniques and talking them seetilation. For example, it does expand the cells of the wood it kind of improves the capillary effect and allow water allows water to move more freely through the mass but it doesn’t necessarily directly improve biological Durability. So It’s not.. It’s not.. It’s It’s not sort of changing the woods relationship with water other than allowing it to move more quickly through the material. So It’s reasonable to think that the performance of thermally modified wood is is oftentimes superior to some of these other processes.

Jessica: Okay, and I think I like the way you say that that it changes, you know, thermal modification changes the woods relationship with water. Um I think that that’s kind of a very kind of concise way to to summarize the value proposition. Um, another thing I want to ask you about was the finished look. So I know sometimes when you get some of these products, when they’re left to weather based on these modifications, often they turn to gray. I mean look at wood, any old barn. I mean I grew up in a 200 year old farmhouse and everything, all the wood of course, had weathered to gray. But, does that happen with Arbor Wood as well?

Jon Heyesen: Yes, it does. So, the process doesn’t improve UV stability. In fact, I believe that Arbor wood tends to lighten faster than traditional non-modified woods. A lot of the naturally occurring tannins and the compounds that give what its color, are some of what get cooked out during the modification process but a lot of people really like that aesthetic and for folks who want to let Arbor Wood move to gray, it could really largely be considered a maintenance free natural wood product.

Jessica: Um, yeah.

Jon Heyesen: But it is also possible to maintain these tones and there are there are fairly standard off the-shelf finishes that work really well with thermally modified wood that would allow somebody to maintain these beautiful rich amber tones and I always like to remind people kind of looking at this sample again that these colors are through colors. So, in the event that the surface of say, an Arbor Wood facade started to move to gray 7 years down the line, it is possible to restore this original color through just a gentle sanding, light pressure washing, something like that.

Jessica: In the fade to gray with thermally modified wood while in other wood types that fade to gray would occur with some degradation of the the wood itself. With thermally modified, you’re not getting that, you’re getting a very durable piece of wood. That color is changing to that gray which people, a lot of people like, use it for that silvery gray. But you’re not getting the breakdown that you normally would over time with with the standard wood.

Jon Heyesen: That’s right, yeah, you don’t really get as fully a weathered looking board. It’s really just silvered out but the physical integrity of the board remains. Yeah.

Jessica: Okay, okay, so you know there are no chemicals introduced so it is you know, very natural. Um, what are some of your favorite installations that you’ve done, that you’re really, particularly proud of.

Jon Heyesen: Um, yeah. None of the largest installations that we’ve been a part of is here in Minnesota. It’s the Bell Museum of natural history. It’s on the St. Paul campus of the University of Minnesota, it’s a LEED Platinum building. It’s a net 0 building. It’s won a bunch of awards, designed by the talented folks at Perkins and Will, and that particular building. A very large Arbor Wood facade, it made use of Minnesota-grown Eastern White Pine that was sourced within 2 hours of the job site. Very, very cool and the university just sort of, as part of the ethos of the museum itself they wanted the building to represent really a living and organic structure and experience and so they wanted thermally modified wood. They wanted to leave it raw, they wanted sort of, the effects of the sun and mother nature to do its thing and allow that facade to just gradually move to silver. And it’s been fun to watch that building transition but very beautiful building. Um, there is a project also here in Minnesota at a public park system Theodore Worth Park and the City of Minneapolis connected with Arbor Wood to repurpose boulevard ash that were impacted by the Emerald ash borer and so these trees were all getting removed anyway and we were able to take those trees, modify them, turn that wood into decking, which was then used for some public boardwalks and walkway systems throughout the wildflower sanctuary. Within this park which is just a really neat story and kind of a testament to the technology, we’re seeing  modified wood anywhere from Brooklyn Bridge Park and you have public parks that are starting to take advantage of this. We’re seeing large retailers that are incorporating modified wood on storefronts. So really kind of throughout North America and really largely throughout the globe, modified wood is becoming less niche and so more and more people care about the materials that are used in their buildings in their homes.

Jessica: Yeah, I mean I think we’ve seen wood make a real resurgence here. You know as people talk about you know Biophilic design and, you know people for a long time, what was seen as kind of the sustainability story of wood, was FSC, that it was responsibly harvested and things like that. And I think you’ve taken, thermally modified is this really natural way to increase the durability. It’s also local, responsibly harvested, multi-species so you’ve kind of really expanded the sustainability story and, you know, kind of telling that story and some of these jobs that you’re talking about you know people really connect to wood as a product. And when you can make it even more durable in longer life I think you know it’s just a natural kind of progression towards using more wood. We see it in a lot of the projects that we work with, it’s just people are incorporating it with you know, hard surfaces and things because it just imparts, it’s the easiest way to bring nature into a space.

Jon Heyesen: Right? Right? I agree and I agree that sort of human beings have this innate need to feel connected with sort of the natural world and the world around us and for many years there were materials that tried to replicate the look of wood. We had composites, we had wood grain embossed.

Jessica: Yes.

Jon Heyesen: Metal siding for example, and now people can get back to using wood again.There are really interesting technologies, the mass timber movement. You know we talk about CLTs (cross-laminated timber) a little bit as a construction methodology and these natural wood modification technologies for finish applications that are making wood relevant, making it exciting. And also making it long lasting.

Jessica: Yeah, we deal with you know, a lot in the sustainable material space. You know, just in building materials, in general. There’s a lot of this copycat stuff. We deal with hard surfaces. So everyone’s trying to look like marble and I find it so odd when you’re trying to copy something. Marble’s a great example. Marble can’t be used in high acid, high wear environments because it wears too easily. So it’s been replaced with these materials that are worse but they look like marble so people are using them and it’s you know, just now that materials are coming out that are better. You know, better for the environment that also looked like marble but at the end of the day if it could just in your case it is the material right? It’s a way to modify the material to address those things rather than come out with some plastic composite trying to look like it. You know, like you were saying with all the exterior composite products with the wood grain and so on.

Jon Heyesen: That’s right, That’s right, yeah and I think you know in the case of Arbor Wood, we produce materials certainly at scale but it is still just an organic natural product that will have its own sort of characteristics from board to board. This is an example of our take on traditional Japanese Yakasugi or shou sugi ban we found that the stability of modified wood, in this case, our modified pine is really a good canvas for applying some of these real charred finishes and we produce this on a real open flame system and…

Jessica: Yes.

Jon Heyesen: It is both consistent and unique at the same time and so it just allows people to have some fun and be creative and have a sense of of personalization or uniqueness when they are thinking about designing their home or designing a building.

Jessica: Yes, yeah, and I think and then that’s a big deal. I think you know someone is building a marquee building or it’s a mountain home or a laycomb or something that they just kind of want to put their fingerprint on and you’re relegated to these vinyl sidings and all this stuff, or you know fake brick and all that stuff. It’s just very neat to have these options out there for them to really choose something that that kind of represents what they’re trying to do.

Jon Heyesen: That’s right.

Jessica: And then I want to ask one last question because you know you don’t want people running outside chopping down a tree and throwing it in their oven thinking they’re gonna get thermally modified wood. This is a very advanced technology that you guys have. This is not just an oven that you’re throwing stuff in, this is a system that came out of Europe, it’s very advanced, there’s not a lot of them in the world. Can you talk a little bit about the technology and why it’s unique to Arbor Wood?

Jon Heyesen: Yeah, it is absolutely specialized technology. It is very high heat and the way these systems work are such to either have nitrogen rich or just oxygen-rived environments. The heat is high enough that it would otherwise combust. And what we’re now seeing is sort of next gen technology and part of what we’re building over this next year is is a new manufacturing facility here in Minnesota bringing in this next gen technology where now we’re incorporating pressurized vessels and pressure into the equation and sort of the inclusion of pressure plus heat plus steam. It requires less energy for modification to happen. It creates more consistent modification and improved durability and we can do some really interesting things like explore the impregnation of say a fire retardant for improved flame spread performance on a natural wood cladding facade and so the technology is. Very much proprietary. It’s been It’s been developed and evolving over these thirty plus years that this industry has existed. So I absolutely would not throw some wood in an oven and it is different than say a traditional drying kiln. A drying kiln is more about reducing moisture content to a specific level, whereas these modification kilns really kind of create that modification reaction at around °c. So we’re talking about pretty high heat environments.

Jessica: And we know that it changes the relationship between the water and the wood all right?

Jon Heyesen: We sure do, that’s the point.

Jessica: Well, thank you so much. This has been great. I’m excited to see what CaraGreen and Arbor Wood can do together and I appreciate you coming on the podcast!

Jon Heyesen: Happy to be here. Thank you so much.

Jessica: This is Build Green Live Green.

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