Structural and dendrochronological characterization of mountain pine persistent woodlands on the Monti del Sole – Dolomiti Bellunesi National Park

High-mountain ecosystems, located at the geographical distribution limit of the species, may provide valuable information about tree-growth responses to changes in climate conditions and land uses. In order to provide a first description of a mountain pine ecotone, at the alpine treeline, three plots were sampled along an altitudinal gradient in the Monti del Sole (Dolomiti Bellunesi National Park, Veneto, Italy) on a northwestern slope from 1850 to 2000 m a.s.l. In order to reconstruct recent dynamics of Pinus mugo Turra ssp. mugo (mountain pine) at this altitudinal range dendroecological methods were used,which allowed reconstructing the age structures of tree populations. Raw mean chronologies showed the long-term variability, related to non-climatic signals due to age, size and stand dynamics. The raw mean chronology of Plot 1 followed the typical exponential negative trend, while raw mean chronologies of Plot 2 and Plot 3 depicted an increasing growth trend, starting from early fifties of 20th century. There was a greater ring width in Plot 2,than the other two plots. These mountain pine scrublands belong the Sorbo chamaemespili - Pinetum mugi association and form persistent woodlands.