Question: Which are the structural attributes and the history of old-growth Fagus forest in Mediterranean montane environments? What are the processes underlying their structural organization? Are these forests stable in time and how does spatial scale affect our assessment of stability? How do these forests compare to other temperate deciduous old-growth forests?
Location: 1600–1850 m a.s.l., Fagus forest near the tree line, central Apennines, Italy.
Methods: An old-growth Fagus forest was studied following historical, structural and dendroecological approaches. History of forest cover changes was analysed using aerial photographs taken in 1945, 1954, 1985 and 1994. The structural analysis was carried out in the primary old-growth portion of the forest using 18 circular and two rectangular plots. Dendroecological analyses were conducted on 32 dominant or co-dominant trees.
Results: These primary old-growth Fagus remnants consist of four patches that escaped logging after World War II. Both living and dead tree components are within the range of structural attributes recognized for old-growth in temperate biomes. Dendroecological analyses revealed the roles of disturbance, competition and climate in structuring the forest. We also identified a persistent Fagus community in which gap-phase regeneration has led to a mono-specific multi-aged stand at spatial scales of a few hectares, characterized by a rotated-sigmoid diameter distribution.
Conclusion: Even at the relatively small spatial scale of this study, high-elevation Apennine Fagus forests can maintain structural characteristics consistent with those of old-growth temperate forests. These results are important for managing old-growth forests in the Mediterranean montane biome.
Nomenclature: Pignatti (1982).
Abbreviations: BAI = Basal area increment; CCTRMD = Computer controlled tree ring measuring device; CV = Coefficient of variation; CWD = Coarse wood debris; DBH = Diameter at breast height; DIB = Diameter inside bark; IGM = Istituto Geografico Militare; OG = Old-growth; PGC = Percentage growth change; PNA = Abruzzo National Park; UTM = Universal transverse Mercator.
