Something old, something new. Technology of thermally modified wood

Science and technology news and technology relevant to South Dakota can be found in some less obvious places like...well like Wood magazine by Better Homes and Gardens.  In the March 2010 WOOD magazine page 20 and 22 is an article titled "The Ultimate Outdoor Wood" on a near ancient process to harden wood that has new uses resulting from modern controlled technology.

Early hunters heated wood spears over fire to harden them.  In the 1990's, Scandinavian manufacturers studied the process in the lab.  Stellac Oy research led to a new industry producing a lighter, harder wood that resists, insects and rot.  It is not a matter of simple heating however.  The process involves heating wood with 14 to 19% in an initial heating to 212 degrees (the boiling point of water). That heat is continued and steam is introduced to slowly bring the wood to around a uniform 8% moisture.

The temperature in the "kiln" is then boosted 480 F degrees. This baking thermally modifies the wood converting tanins and sugars by "baking" them until they are inedible to microbes and insects.  The wood also darkens and hardens.  Steam is then again introduced to stabilize the wood and prevent complete drying.

The thermally modified wood is then slowly cooled for 24 to 48 hours to minimize stresses in the wood. The resulting wood is lighter in weight than untreated wood and dimensionally stable and resistant to warping and decay.  The downside is that the wood is more likely to split and drilled holes for screws should be used near ends of dimensional lumber.

Currently most of the thermally modified wood in the US starts with southern pine since it is available and less expensive.  The resulting product is currently similar in price to treated woods or to wood and plastic composite wood. The modified wood is enough lighter than treated wood that nearly twice as much can be hauled on loaded trucks.

Several companies are now making the wood product.  These include Radiance Wood Products , EcoVantage , Bay Tree Technologies , and Northland Forest Products . I have not checked these sites for information however.

I don't know enough about wood and bark beetles or this product system  to perhaps make informed suggestions, but it seems to me that this process would open new options for wood production with a somewhat unique resulting product if such an operation system could be set up in the Black Hills of South Dakota.  This may be a new opportunity for South Dakota.

[[ Note added October 10, 2011]]  I thought this idea was in this post, but I failed to get it in here.  SDSM&T, SUSD, should be doing research on developing a portable treatment systesm to make beetle-infested wood safe for movement without danger of spreading the problem. David Trask at Mt. Blogmore added a good link to a discussion there and I am including that below.

Colorado Bark Beetle Federal Research publication links

As a matter of curiosity, I would like to see what this does to cottonwood lumber which on its own can turn into something hard enough that it is nearly impossible to drive a nail into it.

Comments welcome... especially if you know more about these processes or about lumber in the Black Hills of South Dakota.

---- Doug Wiken with information primarily from WOOD magazine.

Comments

[Ken-huck]

Thanks for posting this Douglas. This sounds really good and I am trying to figure if this is a cradle to cradle product.
Wood being a biological nutrient can be composted. Can thermally modified wood be composted just at a slower rate? My guess is that some organisms will eat it but will prefer other things.
Is this stuff rated for direct ground contact?

[[ Note from Wiken: I can't really answer your questions. There is more information at the links in the post which may provide answers or locations where you can find more info.

The heating is claimed to change the structure of the wood and availability of nutrients attractive to insects, bacteria, fungus, etc into something indigestible. No source of the stuff around here. I posted the info in the hopes that a South Dakota lumber company would consider manufacturing the product. Right now I don't have time to do much more research on the product. Mar 26, 2010 ]]]