2.2 Forest Inventory Methods
REMOTE study sites are distributed along the latitudinal extent of the Carpathian Arc, and encompass a sizable altitudinal gradient (approximately 600-1700 a.s.l.). Once primary fragments were located, a contiguous internal study site (henceforth, stand), was delineated. Stands vary in size from 10 to 60 ha, though most stands are approximately 30 ha. Inventory plots were randomly distributed along the corners of a regular square-celled grid to ensure a stratified random design. For Picea stands, grid spacing was 1-2 ha cells, for Fagus, grid resolution was 10 ha. In total, the dataset consists of 538 0.1 ha plots located in 38 Picea -dominated stands and 278 plots located in 21 Fagus -dominated fragments (Fig 2). Piceaconstitutes over 95% of the individuals in Picea -dominated stands, whereas Fagus constitutes approximately 75% of individuals in Fagus -dominated stands, with Abies alba ,Acer psuedoplatanus and Picea abies contributing an additional 24%.
Within inventory plots, all trees >10 cm in diameter at breast height (dbh) were identified and mapped. During inventory, trees were assigned to one of two competition classes: individuals taller than mean canopy height were designated to the overstory category and individuals below mean canopy height were designated understory. Inventory data were used to estimate stem densities and basal areas. Importantly for our analysis, there are no strong geographic patterns in the stand structure, which could otherwise alter our interpretation of the drivers of growth variability, though it should be noted though that basal areas and stem densities were weakly positively correlated with elevation (r = .21 and .15, respectively).