Economic Evaluation of Mechanized Pruning of Coffee in Hawaii

Abstract

Marketable coffee (Coffea arabica) yield and cost of production under two systems of mechanized pruning—hedging and stumping— were investigated. Data were collected from 1997 to 2001—a single pruning cycle—on three cultivars on three farms on Kauai, Maui, and Molokai. Treatments were variations of hedging and stumping, including time of pruning, methods of re-growth control, and tree in-row spacing were applied to each coffee cultivar. Economic evaluation was based on a partial budget analysis of the actual costs per year of the different pruning systems used on each farm. Mechanical pruning costs per acre for best hedging and stumping treatments across cultivars were 90% and 83% less, respectively, than the current practice of manual pruning. Response to pruning system varied according to coffee cultivar, tree in-row spacing and farm location. The tall cultivar Mokka had higher yields when hedged at 5 ft (1.5 m) tall and 5 ft wide, and the semi-dwarf cultivar Yellow Catuai had higher yields when stumped at 2 ft (0.6 m) tall. Hedge pruning should be done early in the year, January to February, for the semi-dwarfs, `Yellow Catuai' and `Red Catuai', but can be delayed until May for `Mokka'. Annual topping in the hedging systems should be done January to May for `Yellow Catuai' but maybe delayed until May for `Mokka' and `Red Catuai' without yield loss. The economic evaluation revealed that the cost of stumping was higher than hedging. For `Yellow Catuai' on Kauai the economic evaluation indicated that although the cost of stumping was higher, the accompanying higher yields resulted in a higher gross margin for this system. When stumping, verti- cal branches can be set with a contact herbicide spray to avoid higher hand pruning costs without lowering yields. Stumps should be narrowed after stumping if spaced, 2.5 ft (0.75 m) the current standard in-row spacing for mechanical harvesting. Wide in-row spacing (5 ft) should be considered by growers when planting or re-planting.