New versus old wood: differences and similarities in physical, mechanical, and chemical properties

Physical, mechanical, and chemical properties of specimens of new and old (17th-century) wood ( Pinus sylvestris L.) from the same locale in Norway were examined. Only slight changes resulted from more than 300 years in an uncontrolled environment. No significant differences were seen in mechanical and physical properties including stress-strain behavior and dimensional moisture isotherms. Chemical changes found in the resin and cellulose were minor. Analysis indicated some hydrolysis of xylan. These results confirm previous work showing that wooden objects of all constructions, including furniture, safely tolerate moderate fluctuations in temperature and relative humidity. Cycling experiments on the present specimens confirmed this. Intact wood is chemically stable over a wide range of environments. The deterioration of furniture and wooden objects is due primarily to other factors, including abuse, extreme changes in temperature or relative humidity (such as hot, dry conditions caused by central heating), biological attack, or liquid water.