Pruning has been seen as a means of improving olive tree productivity. The presumed importance of pruning was described by Columella (born 4 AD), and has persisted in general terms to the present. In this work, the effect of different pruning regimes was assessed from two field trials conducted in Mirandela, NE Portugal, in an olive grove of cv. ‘Cobrançosa’, rainfed managed. The first trial began after a light crop (“off” year) and received four pruning regimes (hard, moderate, light, and nonpruned control). The second trial started the following year, after a heavy crop (“on” year), and received two pruning regimes (hard and nonpruning). The study was carried out from 2012 to 2016. The accumulated crops of the four harvests performed after pruning in the first experiment did not significantly vary among nonpruning (8754 kg ha-1), slight pruning (8850 kg ha-1), and moderate pruning (8334 kg ha-1) but was significantly lower in hard pruning (6449 kg ha-1). The olive trees showed a high plasticity or tolerance to pruning, since olive yield did not decrease in response to light or moderate pruning regimes. It seems that it is possible to carry out light to moderate pruning to achieve several objectives of orchard management without significant loss of production. The results also showed that if pruning is done under a hard regime it should only be performed after a heavy crop. In addition, if done under a light regime, pruning can also reduce the alternate-year bearing behavior of the olive tree.
