Fig. 4: Nutrients concentration in foliar tissue of living SBW host trees with annual progression of the outbreak.
From: Defoliation-induced changes in foliage quality may trigger broad-scale insect outbreaks
Fitted relationships for nitrogen (a), phosphorus (b), and potassium (c) concentrations (g kg−1) and C:N ratio (d) with years (calendar years) and stand composition in needles taken off branches of living balsam fir and black spruce trees. Shaded areas indicate 95% confidence intervals. Slopes significantly different from zero are identified with an asterisk. Lowercase letters in color compare slopes among stand composition (when the interaction between year and stand type was included in the model) and uppercase letters in black compare slopes between species. Total sample size was 1693 observations.
