Drought can favour the growth of small in relation to tall trees in mature stands of Norway spruce and European beech

Forest Ecosystems

Table 6 Upper part: Results of the pairwise comparisons by fitting Eqs. 2a, 2b (corresponding to Q2)

Pairwise comparisons with regression models after Eq. 1
Comparison	a ₀	SE	a ₁	SE	b ₀	SE	b ₁	SE	R ²	p (model)
Intercept N.sp. all vs. E.be. all	0.0068*	0.0030	−0.0103*	0.0044	−0.0005**	0.0002	0.0004	0.0002	0.48	0.000
Slope N.sp. all vs. E.be. all	0.0018	0.0111	0.0225	0.0157	0.0017**	0.0005	−0.0013	0.0008	0.27	0.013
Intercept N.sp. mono vs. N.sp. mixed	0.0083	0.0049	−0.0077	0.0069	−0.0006*	0.0002	0.0006	0.0003	0.46	0.000
Slope N.sp. mono vs. N.sp. mixed	0.0000	0.0123	0.0067	0.0174	0.0019**	0.0006	−0.0007	0.0009	0.38	0.001
Intercept E.be. mono vs. E.be. mixed	−0.0008	0.0040	−0.0044	0.0056	−0.0001	0.0002	−0.0001	0.0003	0.54	0.000
Slope E.be. mono vs. E.be. mixed	0.0230	0.0121	0.0014	0.0171	0.0006	0.0006	−0.0001	0.0008	0.05	0.583
Resulting linear models intercept = a + bM_gs, slope = a + bM_gs.
Category	a	b		diff
Intercept N.sp. all	0.0068	−0.0005		A	diff A is due to a difference in intercept only (p = 0.010)
Intercept E.be. all	−0.0034	− 0.0001		A
Slope N.sp. all	0.0018	0.0017
Slope E.be. all	0.0243	0.0005
Intercept N.sp. mono	0.0083	−0.0006
Intercept N.sp. mixed	0.0006	0.0000
Slope N.sp. mono	0.0000	0.0019
Slope N.sp. mixed	0.0067	0.0013
Intercept E.be. mono	−0.0008	−0.0001
Intercept E.be. mixed	−0.0052	− 0.0002
Slope E.be. mono	0.0230	0.0006
Slope E.be. mixed	0.0244	0.0005

Lower part: Linear models for the different species/stand categories resulting from combining the corresponding parameter estimates from the upper part. If two categories have the same letter under ‘diff’, their linear models differ significantly due to the significances shown in the upper part of the table. Not all possible combinations of categories were tested against each other; see column ‘comparison’ for the performed tests. N.sp.: Norway spruce. E.be.: European beech. Significant differences of the parameters between the groups are indicated by the levels of significance (*p < 0.05, **p < 0.01, ***p < 0.001)