In 2002, 39 impact assessment plots were established and 644 cores were collected for analyses from Interior Douglas-fir sites in the Kamloops Region. The tree ring collection and analyses will complete a data set that has been compiled over the past 3 years. This data will be used to determine impact and historic outbreak patterns of the western spruce budworm, Choristoneura occidentalis, throughout its range in the Kamloops Region. There were 8 outbreak periods identified in the tree ring chronologies over a number of sites. Outbreak duration was between 5 to 8 years and the number of years between outbreak periods ranged from 10 to 48 years. Not all sites experienced each of these outbreaks therefore outbreak periodicity would vary from site to site. Lorraine Maclauchlan.
MacLauchlan, Lorraine, British Columbia Ministry of Forests - Southern Interior Forest Region. 2003. Investigation into the impact and historic occurrence of western spruce budworm, Choristoneura occidentalis, in the Kamloops region. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2003MR356