MECHANICAL OUVE HARVESTING SYSTEMS Arlindo Almeida, Escola Superior Agrária de Braganca, Braganca - Portugal Sousa D. Reynolds R&O, Monte da Granja, Estremoz.- Portugal Bento A. Dias, Oliveira J. Peca and A. Pinheiro Universidade de Evora, Evora. - Portugal Joao Lopes Dir. Regional de Agricultura de Trás-os- Montes, Mirandela.- Portugal Luis S. Santos Departamento de Olivicultura da E.N.F.V.N., Elvas.- Portugal Keywords: Olives mechanical harvesting/three collecting systems. Abstract Trunk or bough shakers for the mechanical harvesting of olives can be complemented by collecting equipment now available: the inverted umbrella and the rolling canvas catching frame. The performance of both is compared with the traditional method of collecting olives on a canvas layed manually under the tree, the fruit being detached by shakers. Work rates and costs are compared under field trials in Portugal (Alentejo and Trás-os- Montes regions). 1. Introduction Olive growing is a traditionally labour intensive actlVlty in Southern European countries. High costs, particularly at harvesting and pruning are increasingly justifying mechanization. Tree shakers are now widely accepted among larger -growers. The harvesting process can be complemented by collecting equipment like the inverted umbrella and the rolling canvas catching frame. However, technical and commercial knowledge about this equipment is lacking, especially in the conditions found in Portuguese agriculture. The inverted umbrella and the rolling canvas catching frame are compared in field trials with the common method of collecting olives on a canvas layed manually under the tree, the fruit being detached by the sarne shaker. 2. Material and methods 2.1. Olive orchards Field trials took place in the two main regions of olive production in Portugal: Alentejo and Trás-os-Montes. Site 1 - Monte da Revenduda, Sousel, Alentejo: a 30 year old olive orchard of the local variety Galega, established on 20% with an of 100 trees per hectare. Tree crowns are between 38 m- and 70 m 3 . TradltlOnal prunmg over the last few years has promoted an excess of wood. A sample of 416 trees was used in the trials. Site 2 - Monte da Granja, Estremoz, Alentejo: a 70 years old olive orchard of the local variety Galega, established on flat land, with an array of 100 trees per hectare. Tree crowns are between 31 m 3 and 79 m 3 . As in site 1, traditional pruning has promoted an excess of wood. A sample of 478 trees was used in the trials. Site 3 - Sucaes, Mirandela, Tras-os-Montes: a 35 year old olive orchard of the local variety Verdeal, established on 10% slopes, with an array of 200 trees per hectare. Tree Proe. 3 rd Int. ISHS Symp. on Olive Growing Eds. LT. Metzidakis and D.G. Voyiatzis Acta Ilor!. 474, ISIlS 1999. 209