Innovation in Wood Products

(This article first appeared in the Fall 2014 issue of Northwest Woodlands. It is published here by permission.)

What will be the log markets of the future? That’s a question for which all foresters and woodland owners would love to have a reliable answer. Whenever I venture into making predictions about the future, I’m reminded of a saying I heard years ago – there are two kinds of people that predict the future: 1) those who don’t know the future and 2) those who don’t know that they don’t know the future. So there’s my disclaimer. While I won’t claim to be able to predict the future, I present here a variety of wood products innovations and their potential implications for future log markets.

The Past (and Present)

For decades, the wood products industry has focused on maximizing the utilization of the forest resource. Said another way, the industry has focused on utilizing waste (e.g., via composite panels like particleboard), minimizing waste, and maximizing yield of sellable products. And of course, that trend continues today. For example, modern sawmills use scanning systems with computer-based optimization to get the maximum volume and/or value from every log. And veneer mills use technologies like ultrasound and video to grade veneer. Multiple types of scanning technologies (e.g., video, laser, and dielectric sensors) are now used to grade finished lumber as well.

Given a growing global population and the accompanying increase in the demand for wood products, the need for process innovations that minimize waste, minimize production costs, and maximize yield will only continue. However, there are newer drivers that are sparking innovation in the wood products industry as well.

The Present (and Future?)

Societal demand for products that are natural, sustainable, and renewable is what appears to be driving much of the innovation in the 21st century wood products industry. And if you’re wondering what specifically is meant by the terms ‘natural, sustainable and renewable’, my experience has been that these concepts are often best defined by contrasts. For example, ‘natural’ is often contrasted with synthetic or artificial. In other words, it’s all about the ‘source.’ For sustainable, the contrast in the forest industry is often with deforestation – of tropical forests in particular. And when considering what is or is not renewable, we often contrast rapidly renewable resources like wood or bamboo with non-renewable resources such as petroleum-based products.

I’ll present several examples of innovations with regards to the specific innovation impetus or driver (i.e., natural, sustainable, or renewable). However, admittedly, this categorization is primarily a convenient way to present a wide variety of innovations. The reality is, there is significant overlap in the natural/sustainable/renewable concepts and of course, many innovations are driven by more than one of these concepts.

Natural

The best way to summarize the ‘natural’ concept as a driver of innovation is with the phrase ‘consider the source.’ There are numerous ‘bio-based products’ made from plant-based resources and many of these products are not new. For example, the pulp & paper industry provides a great deal of products beyond pulp. Byproducts of chemical pulping include crude tall oil, crude sulphate turpentine, and lignin. These products are chemical feedstocks that are used to produce a wide array of products such as adhesives, fragrances, cleaners (e.g., Pine-Sol®), turpentine, food additives (e.g., glycerol ester of wood rosin – an additive for citrus-flavored beverages), rosin that baseball pitchers use, etc.

Again, these products aren’t new. The innovation in this sector may in fact be a return to past practices as the interest in natural products increases. I had the opportunity to visit Diamond G Forest Products, a small family business in southeast Georgia, a couple years ago. In addition to producing pine lumber, this company taps their pine trees for ‘pine gum’ (see Figure 1). They collect the gum in plastic bags and distill it. The condensed vapors are turpentine and the solid fraction is pine rosin. Of course, the basic source is essentially the same as when these products are produced from chemical pulping. The difference may be primarily in that the production process itself seems far more ‘natural.’

Tapping pine trees for pine gum
Figure 1. Tapping pine trees for pine gum

Other products that have garnered media attention in recent years include bio-based plastics. And this example covers both the ‘natural’ and ‘renewable’ innovation drivers. For example, both Pepsi and Coke have announced using ‘plant-based’ materials for their PET (polyethylene terephthalate) bottles. Pepsi’s March 15, 2011, news release states that the bottle is “…made from bio-based raw materials including switch grass, pine bark, and corn husks.”

As another example, Tecnaro, a German firm, invented a product known as Arboform® that they also refer to as ‘liquid wood.’ Arboform® is a thermoplastic material made entirely from lignin, another byproduct of pulping. As you can see from Figure 2, it can be used to make products commonly made from plastic. Hence these ‘liquid wood’ products are an alternative to plastics made from petroleum.

Figure 2. Products from Arboform® (Source: www.tecnaro.de)
Figure 2. Products from Arboform® (Source: http://www.tecnaro.de)

More generally, there is a trend related to ‘green chemistry’ and natural sources for common chemicals. For example, Dr. Kaichang Li at Oregon State University (OSU) invented a new formaldehyde-free adhesive for the wood products industry that is based on soybean protein. This adhesive is now being used throughout Columbia Forest Products’ hardwood plywood operations and marketed in the company’s PureBond® products. Other hardwood plywood firms have also developed soy-based adhesives.

The final example I will give in this category is related to wood preservatives from natural sources. I’m not aware of any major commercial successes yet in this area. However, research has been conducted for years on the use of various plant-based compounds for wood preservatives. For example, cinnamon leaf oil has been tested as a natural wood preservative. And a graduate student at OSU recently tested oils distilled from the foliage of western juniper. When tested on small pine blocks, the juniper oil was highly effective in providing resistance to termites and fungi. Commercializing this invention will require finding a cost-effective way to extract the oils, determining the required minimal concentration, and perhaps the most significant challenge, finding an environmentally-friendly method to apply and ‘fix’ the preservatives in the wood; a key challenge is preventing wood preservatives from leaching out of the wood when the wood gets wet.

Sustainable

As stated above, in the forest industry, the concept of sustainability is often presented in contrast to deforestation in the tropics. Many innovations in wood products have come about in recent years that are marketed as alternatives to tropical hardwoods. The overarching theme for many of these innovations is that of wood modification. Wood may be modified by chemical impregnation, thermal treatment, or mechanical treatment. As with many innovations discussed above, these concepts by themselves are not entirely new. For example, with respect to thermal modification, centuries ago the hulls of wooden ships were charred as a means to increase durability. However, what is new is more sophisticated means available nowadays to control the treating conditions and as a result, the material properties. Further, some technologies that were developed decades ago are just recently seeing commercial success.

We’ll begin with polymer impregnation. There are companies that produce products such as flooring, tabletops, and countertops that pressure impregnate wood with polymers such as acrylic to harden the surface. For example, Nydree Flooring in Pennsylvania impregnates oak veneer with liquid acrylic that then polymerizes and hardens within the wood cells. As they state, the product is “…300 percent more durable than standard engineered wood flooring.”

And Torzo Sustainable Surfaces is a new company in Woodburn, Ore., that produces polymer-impregnated panels for tabletops, countertops, wall panels, etc. They combine the ‘natural’ and ‘sustainable’ categories in that they use wood, as well as wheat straw, sunflower hulls, sorghum, and hemp.

Acetylation is another innovation that falls into the category of wood modification. The technology has been around for several decades. In fact, the first patent for acetylating wood was issued in Austria in 1930. However, commercial success for acetylated wood has only come about in the last 10 years or so. Accsys Technologies in The Netherlands is marketing acetylated radiata pine as Accoya® wood. The process involves using vacuum to impregnate wood with acetic anhydride followed by heat. The acetic anhydride alters the chemistry of the wood such that it has a greatly reduced tendency to adsorb water. The result is wood that is far more dimensionally stable, harder, and resistant to fungi and termites. Acetylated wood is being used for a wide variety of exterior products such as siding, windows, doors, shutters, bridges, etc.

The bottom line is that, by acetylating the wood, short-rotation, non-durable plantation species like radiata pine are made suitable for purposes previously restricted to slower-grown naturally-durable wood species. In fact, Accsys Technologies makes precisely this point in their advertising – “Accoya® has properties that match or exceed those of the best tropical hardwoods and treated woods, yet is manufactured using wood from sustainable sources.”

You may notice that we have a theme of ‘better living through chemistry’ developing here and that continues with the next example – furfurylation. This is another process by which non-durable wood species such as southern yellow pine, Scots pine, radiata pine, and maple are impregnated with a chemical (furfuryl alcohol, a byproduct of sugar production) that then polymerizes within the wood cells. The product is being marketed as Kebony® by a Norwegian firm of the same name. As with acetylated wood, the company states that one driver for the innovation is to produce a “…sustainable alternative to hardwoods from tropical regions.”

Wood modification is possible without the use of chemicals; thermal modification is an example of one such technology. The basic premise is still about chemistry though – the wood is heated to over 400° F in a special kiln and the result of these very high temperatures is to alter the chemistry of the wood such that it is more durable and stable. The process was developed in Finland in the 1990s and is used on non-durable species. Target markets include a wide variety of exterior applications such as decking, siding, doors, windows, spas, saunas, fencing, outdoor furniture, etc. And in keeping with the sustainability (and renewability) theme, Cambia, a U.S. producer of thermally-modified wood, states that their product is “…an environmentally responsible choice to tropical hardwoods or petrochemical-based wood alternatives.”

Lastly, Dr. Fred Kamke at OSU patented a process known as VTC wood – short for viscoelastic thermal compressed wood. This wood-modification process differs from the processes described above in that it relies primarily on mechanical rather than chemical or thermal modification. In simple terms, VTC wood is made by getting wood hot and wet and then applying pressure to essentially flatten the wood cells and thereby remove the pore spaces. Such an effect could be achieved via pressure alone, however the VTC process densifies the wood without damaging the wood structure. The result is an increase in stiffness approximately proportional to the increase in density. For example, in one research project, untreated hybrid poplar boards began with a density of about 21 lbs/ft3 and a bending stiffness (modulus of elasticity – MOE) of 1.26 million psi. After being densified to 42 lbs/ft3, the boards had an MOE of 2.32 million psi. Research is ongoing for markets that can capitalize on this process and for a means to conduct the densification on an industrial scale.

Renewable

While many of the innovations presented above could also be categorized as being driven by an emphasis on renewable materials, there are a few for which that appears to be the primary focus. For example, in just the past few years, we’ve noticed several new consumer products made from wood that are traditionally made from non-renewable sources like plastics and metals. Examples include:

‘All of the Above’ – Natural, Sustainable, and Renewable!

No discussion of innovation in the wood products industry would be complete without a discussion of green building and cross-laminated timber (CLT). There has been a lot of attention in recent years to the fact that wood buildings can have a lower environmental impact than structures made of concrete and steel. However, concerns for seismic and fire performance, and the accompanying building codes, have limited wood’s use to residential and low-rise construction. But a relatively new product known as CLT is changing the rules of the game.

CLT was invented in Switzerland in the early 1990s. It is often referred to as ‘plywood on steroids.’ Structural plywood is made by cross-laminating (alternating the grain direction) veneer while CLT is made by cross-laminating lumber. Large panels can be made similar to the way glulam beams are made and these panels are then machined to create openings for windows, doors, plumbing and electrical, etc. The panels are then lifted into place by a crane and multi-story structures can be made in a fraction of the time required to construct concrete and steel buildings. For example, the 9-story Stadthaus CLT structure in London was built in 49 weeks; an equivalent concrete structure was estimated to require 72 weeks to build.

CLT is generating a lot of buzz among the green building and architecture community as it is opening the door for multi-story wood structures. In fact, Vancouver architect Michael Green discussed a 30-story wood structure in a TED talk.

One concern that always arises with ‘wood skyscrapers’ is seismic and fire performance. However, a seismic test conducted in Japan on a 7-story CLT structure showed what we’ve known for centuries about wood – it is amazingly flexible and resilient. The structure showed no apparent damage even after a simulated 7.2 quake. Similarly with regards to fire performance. We’ve also known for years that massive timber structures perform well in fires due to the char layer developing on the wood which then serves to insulate the structural members from further damage. Another test in Japan on a CLT structure demonstrated that fact.

Implications for Log Markets

Of all the innovations discussed above, I believe CLT is the technology likely to have the most direct impact on the Northwest forest industry. This product capitalizes on the strength of solid-sawn softwood lumber – and of course, the Pacific Northwest is king in production of softwood structural lumber. CLT manufacturing capacity is slowly growing in North America. There is now one CLT manufacturing facility in Quebec (Nordic Engineered Wood), two firms in British Columbia (CST Innovations and Structurlam), and one in Montana (Smartlam). In March of this year (2014), Idaho Forest Group announced a joint-venture with Austrian Firm KLH to market and distribute CLT in the United States. Should a significant shift occur to the use of CLT in the construction trade, we are sure to see accompanying growth in the market for sawn lumber.

Beyond CLT, for many of the innovations presented above, it’s difficult to forecast the linkages to log markets. Innovations in biomass, bioenergy, and bio-based products are focused largely on the use of residues of forestry operations (e.g., logging slash and non-merchantable timber) and to some extent, purpose grown crops like hybrid poplar for transportation fuels. At the least, it seems clear that the development of a wood-based biofuels market in the Northwest will impact markets for residues.

Lastly, with regards to wood modification and ‘better living through chemistry’, many innovations are resulting in making wood quality less of an issue; foresters simply need to do what many have done for decades and that is – grow more fiber, faster!

By Scott Leavengood, director, Oregon Wood Innovation Center, Oregon State University