The Relationships among Tree Mixture, Management Type, Stand Density and Diameter Increment in Kazdağı Fir (Abies nordmanniana subsp. equi-trojani [Asch. & Sint. ex Boiss] Coode & Cullen) Forests

Tree mixture may increase stand productivity while forest tree density mostly negatively influence the tree growth. However, several research have indicated that the knowledge on the corelation between tree mixture and stand productivity is still limited. In this study, the relationships among tree mixture, stand type (i.e., even-aged versus uneven-aged), density and diameter increment of Kazdağı fir (Abies nordmanniana subsp. equi-trojani [Asch. & Sint. ex Boiss] Coode & Cullen) were examined. The research was conducted within the Ayancık Forest Management Directorate, Sinop Regional Directorate of Forestry. Four different stands were selected; a) uneven-aged fir stand, b) even-aged fir stand, c) uneven-aged mixed fir-beech stand, and d) even-aged mixed fir-beech stand. Five-year diameter increment in these four different stand types was determined and compared. Random effects regression analysis was utilized to examine the influence of the mixture and tree density on the diameter increment. Statistical relationships were found among tree mixture, stand density and the diameter increment (p<0.05). Moreover, diameter increment varied among the stand types