*2.2. Field Measurements*

A regular 100 m grid with 40 sampling points was superimposed on the core areas of Janj (summer 2011) and Lom (summer 2010), resulting in 80 plots in total. This square lattice arrangement of sample plots is a conventional forest inventory sampling procedure [14]. Each grid intersection defined the center of a circular sampling plot (radius = 12 m, area = 452 m2). In each plot, all live trees with DBH >7.5 cm were tallied and sorted by species. In the understory of both old-growth forests, a total of 1090 trees were counted including 880 beeches, 125 firs, and 85 spruces, whereas in the canopy layer of both forests, a total of 605 trees were counted, which included 191 beeches, 252 firs, and 162 spruces. In addition, the DBH of all trees exceeding the inventory threshold were measured in two perpendicular directions to the nearest 0.1 cm. In the subsequent analysis, only a single DBH value was used for each tree obtained as a mean of the two perpendicular measurements.
