Stand structure and spatial distribution of trees at different developmental stages and stand layers in mixed stands in Artvin region, Turkey

Abstract

The objective of this study is to determine the stand structure and spatial distribution patterns in rare mixed stands of Oriental spruce (Picea orientalis L.), Scots pine (Pinus sylvestris L.) and Caucasian fir (Abies nordmanniana (Stev.) Spach. subsp. nordmanniana). The study was conducted in Ovacik Forests of Artvin, Turkey in 2016. To evaluate stand structure, the distribution of tree species was determined according to developmental stage (seedling- thicket stage; sapling- pole stage; small wood stage; medium - large wood stage) and vertical structure (overstory, middlestory and understory). Spatial distribution of trees was analyzed using Ripley’s K function in ArcGIS. Results showed that all three species contributed to the mixed stand. Caucasian fir dominated in in all plots and plots had a layered structure. Spatial analyses revealed that all trees showed clumped distributions (p<0.01) at smaller scales. Scots pine and Caucasian fir mostly showed random distribution whereas Oriental spruce showed a clumped distribution at 0–7 m scales. Each of the tree species at the medium wood developmental stage showed random distributions at all scales. Clumped distribution was observed in the middle and understory while trees in the overstory layer were randomly distributed