Growth and resource allocation in male and female Populus temula trees. Boxes representing females (F) are coloured pink and males (M) coloured blue, in the Umeå Aspen (Um) and Swedish Aspen (Sw) collections. (a) Growth rate calculated as height increment over five years in SwAsp. Analysis of Variance (ANOVA) results showed no significant sex differences (F1,45 = 0.448, P =0.507) (b) Individual leaf area in UmAsp and SwAsp. ANOVA results showed no significant sex differences for samples from either the Um (F1,38 = 0.958, P =0.334) or Sw (F1,44 = 0.012, P =0.914) collections. (c) Foliar carbon/nitrogen ratio in Um. ANOVA results showed no significant sex differences (F1,38 = 0.631, P =0.432).