A new laboratory technique to simulate the initiation of wood decay and to assess the effects of
incipient decay on material properties is described. Douglas-fir heartwood specimens were exposed
to brown-rot (Po'orrra pl~rrnra and Glo~oph.~Uum rruhcum) iungi for various penods. Bendlng properties
were determined by nondestructive and destructive tests, and chem~cal composilion of spec~men~ was
analyzed. Welght losses of I lo 18% were Innearl? related to strength losses of5 tu 70%. Wood strength
loss bv hrou11-rot fungi was also closel! relaled to desradatron of hem~ccllulosr. comDonents. Hemscellulose
sidechains, such as arahinose and galactose, were degraded in the earliest stages of decay;
main-chain hemicellulose carbohydrates, such as mannose and xylose, were degraded in the later
stages. Changes in glucose content, a measure of residual cellulose, were minimal. Our technique was
effective for establishing and assessing brown-rot decay.