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).