ANNUAL GROWTH DYNAMICS OF ELEVEN HAZELNUT VARIETIES IN NORTHERN PORTUGAL
Seventy five trees of eleven commercial hazelnut varieties were planted 5x3 m apart, and trained as multistemed shrubs, without any prunings. Their growth was evaluated from second year and on, during seven consecutive growing seasons, by annual sampling twenty shoots per tree. Shoot growth was recorded during the nineteen weeks subsequent to spring bursting. A Gompertz function was adjusted to the growth measurements and its estimated coefficients were interpreted. Tree establishment was independent of varietal recorded characteristics (vigor, stem No. and initial root quality) and annual shoot growth rates were very similar among varieties, all over the period under study. When crown competition began, by the 5th leaf cycle, long and short shoot growth suffered stronger reduction on bigger trees than on smaller ones, suggesting the need of appropriate spacements, according to different varietal crown volumes. Intense nut yield quantity and quality reduction from the seventh year on resulted.
Santos, A., Silva, A. and Colaço, J. (1994). ANNUAL GROWTH DYNAMICS OF ELEVEN HAZELNUT VARIETIES IN NORTHERN PORTUGAL. Acta Hortic. 351, 93-98