How old is the ThermoWood technology?

Actually, heat treatment is a method used since the Vikings. First heat treatment studies were made by German scientists in 1930’s and ThermoWood technology was introduced in the 90’s. Then heavily used and further perfected by the Scandinavians. Nowadays leading European companies like Novawood apply this technology to non tropical Hardwoods to allow specific timber species to be used externally aswell as internally.