Rootstock influences the construction costs of 'Starkspur Supreme Delicious' apple trees

The construction costs (CCcomp) of vegetative and reproductive components, and total tree (total CC) and net (CCnet) construction costs were calculate d using the gross heat of combustion, percentage ash content, and total nit rogen for 'Starkspur Supreme Delicious' apple trees (Malus domestica Borkh) grafted onto MAC.24, M.7 EMLA, M.26 EMLA, M.9 EMLA, MAC.9, and M.27 EMLA. The CCcomp in Oct./Nov. of 1-yr wood, 2-yr wood, and roots was Lower in tre es grafted onto more: dwarfing rootstocks than in those on more vigorous ro otstocks. Leaves had the highest CCcomp. Frame, 2-yr, 1-yr, shoot, and root had similar CCcomp. Fruit and spurs had the lowest CCcomp. As tree size de creased, total CC and CCnet decreased.