Long-term effect of fertilization on stone pine growth and cone production

Abstract

Key message: Fertilization is a feasible management technique for Pinus pineaL. cropping, with increased cone production up to 9 years after the application and superior trunk diameter growth every year. Fertilization effects on cone size-weight indicate the value of re-fertilizing. Context: Stone pine (Pinus pinea) is a species of economic interest for its highly in demand pine nuts. Despite the high value of pine nuts, cones are harvested mostly from non-managed forests. Consequently, advances in cropping techniques, such as fertilization, are needed. Aims: To monitor the effect of fertilization on growth and cone production during 10 years after fertilization, adjusted to soil characteristics, on a 16-year-old stone pine orchard. Methods: A fertilization trial including fertilized and non-fertilized plots was established. Diameter (trunk and crown) and height were repeatedly measured in each tree for 10 years. Cones were annually harvested from each tree and counted. Results: Stone pine cone production increased significantly from the third to the ninth year of treatment, with a peak increase of 3.3 times. Conclusion: Fertilization was a useful silvicultural practice to increase stone pine cone production. Periodical fertilization is recommended.