Table 3. The ANCOVA table of the effects of genotype, block and site on total mean abundance of herbivores (log[x+1] transformed) of B. pendula saplings in 2002–2003.

Sapling size index, which is a measure of height and number of leaves (see material and methods), was used as a covariate.

	Mean abundance 2002				Mean abundance 2003
	df	SS	F	p	df	SS	F	p
Genotype	21	1.10	2.82	0.011	21	0.26	1.08	0.435
Error	21	0.39			21	0.24
Site	1	1.13	14.6	0.004	1	0.59	46.7	< 0.001
Error	9.6	0.75			26.7	0.34
G × S	21	0.39	1.00	0.470	21	0.24	1.81	0.019
Error	208	3.88			208	1.30
Block (Site)	10	0.77	4.11	< 0.001	10	0.16	2.55	0.006
Error	208	3.88			208	1.30
Size index	1	0.30	16.3	< 0.001	1	0.23	36.4	< 0.001
Error	208	3.88			208	1.30