The investigation was carried out in 1994 in the Experimental Farm of the Community of Navarra, Spain, with the objective of inducing chemical and hand thinning of fruits in ‘Royal Gala’ apple, established in a density of 6,600 trees×ha-1, using different useful chemical products in the agriculture, and the evaluation of the interaction between the tree vigor of the trees and the efficiency of the thinning of fruits. Of the used chemical products, the carbaryl was the one that showed, in its three concentrations the higher abscission of fruits per tree, without affecting tree production. As the carbaryl concentration was increased the quantity of fruits by tree was redused and the quantity of commertial quality fruits was in creased. The hand thinning leaving a single fruit each 15 to 20 cm of shoot lenght showed that the quantity of fruits for tree was the appropiate having commercial quality without affecting production and neither the yield. One fruit per corymb left, showed high quantity per tree, but quality decreases. It was found that for each one tenth in the increment of the index of productivity of commercial fruits,as a result of the increase of the area of the traverse section of the trunk, the production of commercial fruits per tre is increased in 1.9 kg×tree-1 and in consequence, the yield is increased in 12.5 t×ha-1.