In a pot experiment with two year old Golden Delicious apple trees on Merton 793 rootstock it has been shown that calcium was actively absorbed during the shoot extension period as well as during summer and autumn. At dormancy, the bark of the trees contributed about 59% to the total calcium content although it contributed only 12% to the total tree mass. During the period of rapid shoot extension the calcium reserves from the permanent structure of the trees made a very important contribution (22.8%) to the total calcium content of the new growth (shoots, leaves, and fruit), suggesting that at least a portion of calcium present in the trees at dormancy was in an exchangeable form.