22 American TMT white oak furniture and flooring By Michael Buckley Thermally Modified Timber (TMT) is not new but TMT oak lumber is. Or at least it is new in Southeast Asia. The softwood industry and the rubber wood processors have been working with TMT for years to improve durability. But each has their own limitations of strength and stability and in some cases the process has been partially successful. Up until now the American hardwood industry has provided TMTmaterial principally in ash and tulipwood to provide exterior solutions. Previously almost all applications for U.S. hardwood species have been restricted to interiors, but not anymore.