Table 1.

Comparison of characteristics of understorey structure, species diversity and restoration success indicators among three thinning treatments. Mean values and standard deviations are shown. The effect of treatments was evaluated using Kruskal–Wallis test. Pair-wise comparison (Wilcoxon test) between control plots and each thinning treatment was done only in case of a significant overall effect. P-values were adjusted by Bonferroni correction.

Variable	Control	Moderate thinning	Wilcoxon test, Z and p-value	Heavy thinning	Wilcoxon test, Z and p-value	K–W test, p-value
Structural variables
Canopy openness (%)	14.6 ± 1.9	15.6 ± 1.7	2.09; 0.074	17.2 ± 3.2	3.79; <0.001	<0.001
Shrub layer (cover, %)	1.8 ± 2.8	5.3 ± 7.7	2.63; 0.014	21.5 ± 22	5.89; <0.001	<0.001
Tree regeneration (cover, %)	10.7 ± 8.2	15.0 ± 8.7	2.59; 0.016	32.2 ± 19.5	5.49; <0.001	<0.001
Herb layer (cover, %)	23.8 ± 12.3	29 ± 9.4	1.97; 0.098	37.4 ± 15.3	3.46; <0.001	<0.001
Species diversity
Species richness (N plot-1)	27.9 ± 9.9	29.9 ± 9.5	1.43; 0.312	34.7 ± 11.3	3.64; <0.001	<0.001
Restoration success
Light-demanding oligotrophic species (N plot-1)	2.6 ± 2.3	2.9 ± 1.8	1.21; 0.47	3.9 ± 2.3	2.97; 0.005	0.007
Shade tolerant species (N plot-1)	5.5 ± 2.5	5.4 ± 2.5	–	6.0 ± 2.7	–	0.272
Native ruderal species (N plot-1)	3.4 ± 1.6	4.2 ± 2.2	1.45; 0.296	5.6 ± 2.4	4.09; <0.001	<0.001
Alien species (N plot-1)	1.2 ± 1.1	1.4 ± 1.2	0.93; 1	1.5 ± 1.3	0.63; 1	0.648