Effect of fertilization on stone pine (Pinus pinea L.) growth and cone yield in a young plantation located in a non-native habitat

LOEWE-MUÑOZ, V.; BALZARINI, M.; DEL RÍO, R.; DELARD, C.

Congreso; XXV IUFRO World Congress; 2019

Stone pine is a species of economic interest for its nutritious and highly demanded pine nuts. Despite this traditional use, cones are harvested mostly from natural forests; advances in techniques for its cultivation as a fruit tree have been limited. Fruit development is characterized by a long cycle (3.5 years), with one-, two- and three-year-old cones occurring simultaneously on the trees; this phenomenon makes the evaluation of management practices even more challenging than in other perennial crops. The objective of this work was to monitor the effect of fertilization on growth and fruiting over time. A fertilization trial with two treatments (fertilized and non-fertilized), was set up in a previously thinned and pruned 16-year-old stone pine plantation in central Chile. In spring 2009, trees of fertilized treatment were treated with macro- and micronutrients. All 3-year-old cones in each tree were harvested, weighed and counted annually for 10 years (2009-2018), diameter (DBH and crown) and height were repeatedly measured. Nine years after fertilization, significant differences were found for DBH and crown diameter growth, with a 32.3% and 20.8% higher annual growth, respectively, in fertilized trees. Significant effects of fertilization on fruiting were evident five years after application, and continued up to the end of the study, leading to cone yields up to 2.6 times higher than in non-fertilized trees. Fertilization also affected cone weight positively. Fertilization was a useful cultural practice to enhance stone pine fruiting and growth. Results suggest the convenience of repeating fertilization to enhance cone production and weight.