The authors tested six commercial pruning harvesters to determine harvesting losses and product contamination when recovering pruning residues from an overgrown olive orchard, typical of Southern Italy. All harvesters used a mechanical pick-up to collect the residues and a shredder to reduce them into chips. Three different pick-up settings were tested and namely: 1 cm above ground level, manufacturer's specification and 3 cm above ground level. Ash content in the shredded material was taken as a measure of contamination. The ash content of uncontaminated branch material collected directly from the trees was 3.5%. Ash content in shredded residues varied between 4.5% and over 5.5%, for the shortest and the longest distance between the pick-up and the soil surface, respectively. In contrast, harvesting losses were weakly (but significantly) related to pick-up setting, and mainly depended on machine type. (C) 2012 Elsevier Ltd. All rights reserved.