Changes in cortical and wood terpenes in Sitka spruce in response to wounding

Terpene levels were measured in bark and wood samples of Sitka spruce (Pice a sitchensis (Bong.) Carriere) trees. The trees that had been selected as e arly or late flushing were subjected to artificial wounding to simulate att ack by the white pine weevil, Pissodes strobi (Peck). Samples were taken at four times during the growing season: before wounding, shortly after wound ing, and two times later in the season. Terpenes were extracted with hexane and quantified by capillary gas chromatography. There were no significant differences in total bark terpenes between early- and late-flushing trees o r between control and wounded trees over all sampling times. There were no significant differences in total wood terpenes between early- and late-flus hing trees or among sampling times, but a statistically significant differe nce was found between control and wounded trees. Eleven individual terpenes accounted for the majority of the terpenes in the extracts. Four bark terp enes showed significant differences with sampling time, two with flushing c lass, and none with treatment. Five wood terpenes showed significant differ ences with sampling time, two with flushing class, and nine with treatment. We concluded that flushing had only a minor effect on bark and wood terpen e profiles and that wounding significantly increased terpene concentration in wood shortly after injury.