Variations in the composition of apple leaves and the errors associated with sampling

Intensive leaf sampling of two Cox apple trees was used to study factors affecting yield of leaf dry matter and the nitrogen and mineral contents of the dry matter. Significant differences were found between main branches of the same tree, between different heights of sampling and between non‐fruiting spur leaves on old wood and leaves on new extension growths. Leaf position on new extension growths also affected composition and there were some significant interactions between the main factors. The significance of the results in relation to routine sampling methods is discussed and the need for further sampling investigations emphasised.