Potential Factors behind the Decline of Pinus pinea Nut Production in Mediterranean Pine Forests

Mediterranean stone pine nut is appreciated for its high economic and nutritional value. Starting in 2012, Pinus pinea production declined throughout the area. The dry cone syndrome associated with this decline introduction of Leptoglossus occidentalis occurred simultaneously. This study aims to evaluate potential reasons behind Lebanon, considering climatic factors invasion L. occidentalis. Correlation analysis was used examine a relationship between yield percentage damaged seeds per cone. Climatic variables were also tested. Two time periods considered analysis: before after 2012. Cone negatively correlated (r = −0.42). From 2012 2017, by 50% increased on average from 3% up 60% 2017. Correlations detected temperature hottest three months year harvesting, temperatures during initiation. A conjunction that include might have affected Lebanon.