Chlorophyll fluorescence of the trunk rather than leaves indicates visual vitality in Eucalyptus saligna

Leaf chlorophyll fluorescence has been used to assess physiological stress effects in trees for at least 30 years. This paper describes a novel method for indicating tree vitality in Eucalyptus saligna Sm using bark chlorophyll fluorescence. A visual vitality index was successfully verified by comparing it with growth measurements such as total leaf area and above ground biomass. Bark and leaf chlorophyll fluorescence were then compared with the visual vitality index in spring, summer and autumn. The relationship between leaf chlorophyll fluorescence and the visual vitality index was weak, even with the one parameter that did show a relationship. There was good evidence for a statistical relationship between bark chlorophyll fluorescence and visual vitality, which may become a useful tool for tree vitality assessments in this species and possibly other tree species.