Umbrella pine cone production is an important forest non-wood product in Portugal, especially in the region of Alcacer do Sal, where it plays an important role to the local development. Traditionally umbrella pine cones are manually harvested, increasing production costs and, above all, with very high accident risk to the workers. The development of equipment for mechanical harvesting started in Italy in the 1980's. Studies report different values for harvesting efficiency and tree damage, the latter in terms of immature cones and branches detached. In this study a trunk shaker was used to evaluate mechanical harvesting both in terms of efficiency and tree damage induced by trunk vibration. In comparison to the manual process, time required for mechanised harvesting was about 1/15th of the time. The results revealed a mechanical harvesting efficiency higher than 86% with negligible tree damage. Inter-annual harvest efficiency variability was also observed.