A dendrochronological analysis of Western redcedar sensitivity to climatic moisture deficit

Abstract

Western redcedars (Thuja plicata Donn ex D. Don) at Royal Roads University, Victoria, BC, were sampled for a dendroclimatological study investigating the relationship between radial growth and climatic moisture deficit (CMD), and visually assessed for vigor and dieback. Radial growth showed the strongest negative correlation to a CMD spanning current year May through June. Radial growth was negatively correlated with a CMD in October of the year prior to ring formation, and positively correlated to a CMD in April of the year prior to ring formation. The results indicate western redcedars are sensitive to moisture stress occurring at specific times during the growing season. Over one-quarter of redcedars assessed exhibited mild to severe signs of dieback, suggesting dieback has begun and is progressing on drier sites. Future growth is likely to be impaired by seasonal temperature increases and altered precipitation patterns projected as part of climate change for southern BC.