Intra- and interspecific competition differently influence growth and stem quality of young oaks (Quercus robur L. and Quercus petraea (Mattuschka) Liebl.)

Table 6 Influence of spatial location of oak trees within groups on the probability of occurrence of potential future crop trees (binary logistic regression analysis)

Response variable	Predictors	β	S.E. β	Wald’s χ²	d.f.	Chi-square test
Potential future crop tree (yes or no) (N = 1,098)	Constant	−2.23	0.13	282.45	1
Potential future crop tree (yes or no) (N = 1,098)	Position in group (1 = inner section, 2 = periphery)	0.59	0.18	10.14	1	χ² = 10.17, p = 0.0014

β log odd ratio, S.E. standard error in 95 % confidence interval, d.f. degree of freedom

ISSN: 1297-966X