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

Table 4 Mean DBH, height and branch-free bole length of target oaks and competing trees from pioneer, mid- to late-successional species or oaks. DBH of competing trees did not vary significantly between different groups of competing species (independent sample t test with bootstrap re-sampling and 10,000 iterations)

Site	Cluster type	Target oak trees								Competing pioneer species			Competing mid- and late-successional species			Competing oaks (intraspecific)
		DBH (cm)		Height (m)		Branch-free bole length (m)				DBH (cm)			DBH (cm)			DBH (cm)
		Mean	S.E.	Mean	S.E.	Mean	S.E.	N	% of total height	Mean	S.E.	N	Mean	S.E.	N	Mean	S.E.	N
Altenheim	Group	7.84	0.3	7.97	0.11	3.7	0.14	28	46	n.a.	n.a.	n.a.	6.10	0.15	210	6.22	0.16	190
Kaisereiche	Group	8.48	0.61	6.75	0.71	4.61	0.28	24	68	8.38	0.8	29	9.03	0.58	33	7.32	0.18	117
Lerchenfeld	Group	10.84	0.47	10.45	0.6	4.62	0.23	25	44	9.22	0.5	55	11	2.93	3	9.88	0.24	159
Gerlingen	Nest	13.48	0.62	10.09	0.18	3.3	0.19	50	33	11.69	0.88	24	9.97	0.67	19	12.25	0.39	97
Gerchsheim	Nest	10.33	0.54	10.37	0.18	4.21	0.2	35	41	11.83	0.97	18	13.7	1	28	9.33	0.29	103
Königheim	Nest	9.71	0.39	10.42	0.19	3.93	0.24	40	38	8.17	0.99	9	11.72	2.01	18	9.23	0.25	172
Leonberg	Nest	9.18	0.29	9.58	0.12	4.22	0.26	55	44	8.05	0.46	49	8.21	0.29	112	8.58	0.18	209

S.E. standard error, N number of target oaks and competitors in each cluster planting stand, n.a. not available

ISSN: 1297-966X