Toward a definition of the range of variability of central European mixedFagus–Abies–Piceaforests: the nearly steady-state forest of Lom (Bosnia and Herzegovina)

Abstract

Knowledge on the range of variability of montane European forests is hampered by limited data on the natural disturbance regime and by the small size of old-growth remnants. We studied the mixed Fagus – Abies – Picea Lom forest reserve (55.8 ha) in Bosnia and Herzegovina at three different scales: a grid of 40 sampling points to describe the structural characteristics and their range of variability, three transects to analyse gap size and gap fraction, and a 1.1 ha permanent plot to reconstruct age structure and disturbance history. The forest is characterized by a high volume of living trees (763 m3·ha–1 in the 55.8 ha core area and 1160 m3·ha–1 in the permanent plot) and of coarse woody debris (327 and 383 m3·ha–1, respectively). The percentages of forest area in canopy and expanded gaps are 19% and 41%, respectively. The median canopy gap size is 76.9 m2 and ranges from 11.1 to 708.0 m2. There are large (up to 120 cm diameter at breast height) and very old trees (441, 432, and 416 years for silver fir ( Abies alba Mill.), Norway spruce ( Picea abies (L.) Karst.), and European beech ( Fagus sylvatica L.), respectively). During the last three centuries, the disturbance patterns have been characterized by single-tree or small group mortality. In central Europe, this forest is at the end of a gradient from forests characterized by intermediate disturbances to those where very small-scale processes predominate.

Comparative Structural Dynamics of the Janj Mixed Old-Growth Mountain Forest in Bosnia and Herzegovina: Are Conifers in a Long-Term Decline?

“…Only low-intensity cuttings have been performed in the buffer zone, mostly in the form of salvage cuttings. Inventory data from Janj was compared with recent inventories of the Lom [47] and Perucica [50] old-growth forests. Perucica is located approx.…”

“…To allow direct comparison with Lom, we followed the methodology described in Motta et al [47]. A regular 100 m grid with 40 sampling points in the core area was superimposed (Figure 1).…”

“…Data for the recent inventory of old-growth Lom originates from Motta et al [47], while data for Perucica was measured in 2011 on 12 square sampling plots (0.50 ha) installed on a regular 1000 × 1000 m grid covering the whole core area of the reserve. Within plots, all trees with dbh ≥ 10 cm were tallied according to species and dbh was measured by Lucic [47].…”

“…Within plots, all trees with dbh ≥ 10 cm were tallied according to species and dbh was measured by Lucic [47]. The data for comparison of structural changes in the three old-growth forests originates from the study of Drinic [44].…”

“…These forests therefore represent an excellent resource for the study of interactions of climatic fluctuations and indirect anthropogenic disturbances, both of which are well documented in the literature [33,[37][38][39][40][41]. The Janj old-growth forest has received less scientific attention [42,43] than the forests of Perucica (e.g., [5,19,[44][45][46]) and Lom [32,47,48]. The aims of this study were (1) to describe the structural changes over a 60-year period in the Janj old-growth forest and (2) to compare and contrast the changes with those in the Lom and Perucica (Bosnia and Herzegovina) old-growth forests and other similar old-growth forests in Europe.…”