Effect of species composition, stand density and site index on the basal area increment of oak trees (Quercus sp.) in mixed stands with beech (Fagus sylvatica L.) in northern France

摘要: We investigated the relationship between tree size and radial growth of oak in mixed oak-beech stands where beech basal area ranged from 0.0 to 98.2%. analysed 30 long-term permanent plots northern France with a total 167 periods 1904 2000. The study was based on nonlinear segmented model individual increment as function diameter at breast height, which is implemented French forest simulator Fagacees. variations slope γ linear branch for oak. found stand density, species composition, site index have significant influence. decreased rising admixture increased quality lower density. effect present corresponds findings physiology below- aboveground competition. Our results underline differences competitiveness dynamics stands.