Hazelnut orchards: one tree or two adjacent trees?

Results are presented from an ongoing hazelnut (Corylus avellana L.) trial comparing two orchard typologies: planting 1 tree or 2 adjacent trees.
The trial was established in January 2013 with the Italian cultivar ‘San Giovanni’, which is well-adapted to the Tarragona hazelnut area.
Data on tree vigor (trunk cross-sectional area, height, volume), nut production and fruit characteristics (nut weight, kernel weight, kernel percentage, kernel size >12 mm, blanks, shriveled kernels, blank spots in kernel cavity and glassy appearance) from 2016 to 2021, are analyzed.
Concerning tree vigor, the 2 adjacent trees were higher in trunk cross-sectional area and volume than those of single trees.
The production of 2 adjacent trees was significantly higher than the single tree only in two years (2017 and 2020). However, the cumulative yield of both systems was not significantly different.
Nuts from the single trees were larger, although no significant differences were found in visual kernel defects (blanks, shriveled kernels, brown spots in kernel cavity, glassy appearance). From these results, it can be concluded that the potential small increase in nut yield in the early years of the orchard does not compensate for the extra cost of the trees for the plantation (2 adjacent trees). Nevertheless, and considering that trees are in their eighth year after planting and in their fifth year of production, it will be interesting to continue to follow this trial in the coming years, at least, until the trees reach the maximum available space between them.

X International Congress on Hazelnut

M. Rovira, A. Romero

Corylus avellana L., orchard typology, training systems

https://doi.org/10.17660/ActaHortic.2023.1379.30