Fig. 2

Influence of neighbourhood competition on dependent variables: DBH, height, HD ratio and branch-free bole length of target oaks grown in four 22- to 26-year-old nest planting stands. Impact of aggregate competition was calculated from a separate generalized linear model (see Eq. 1 in ‘Materials and methods’ section) that combined all competitors irrespective of species and precluded additive effects of different plant groups. Impact of competition from conspecific oaks, pioneer and mid- and late-successional species was estimated as interaction effects on dependent variables in another model (see Eq. 2 in ‘Materials and methods’ section). Thin bars represent a standard error of parameter estimates and should not touch the zero line for a significant effect