Evaluation of canopy elasticity, light penetration and reciprocal shading for optimal canopy management in high density hedgerow olive orchards

Canopy management is one of the most important factors influencing yield and economic life of high density hedgerow olive orchards. Currently, the canopy volume is set mainly on the basis of size of over-head harvesting machines; this is a limit for natural growth of trees which have to be pruned hard once the allotted canopy size is reached. Thus, in these sorts of orchards, growers have to find the optimal canopy management in order to control canopy growth and keep the canopy productive (high-yield efficiency). Three main factors have to be considered in canopy management: adaptation of canopy to over-head harvesting machines, light penetration and reciprocal shading. Over-head harvesting machines require elastic canopy in the part exceeding the projection of conveyor frames. Pruning operations have to be set in order to eliminate branches which are not elastic enough to bend down. Elasticity requirements were calculated in 'Arbequina' and 'Maurino' and branch sizes in relation to their branching position are discussed. Light penetration influences the light environment experienced by each shoot. Light environment influences flowering potential of bearing shoots. Effects of selective pruning and topping on light penetration in the canopy of 'Arbequina' and 'Maurino' are compared. Canopy size effect on shading of nearby row was then studied and compared between rows pruned by topping cuts and selective side pruning. In conclusion, tree canopy size can be increased but pruning should keep canopy elastic and enough porous in order to allow light penetration and flowering in the whole canopy volume. Increasing canopy size does not increase significantly reciprocal shading between rows but at the same time it may allow to keep fruit yield steady once tree canopy fills the allotted space