The residual ash-sycamore stands in the Vaser valley (Viseu forest district): typology and importance for phytodiversity conservation
2006
HORJ, P. + GAFTA, D. + GROZA, G.
The cluster analysis and non-metric scaling of eight phytosociological releves, performed in mixed ash-sycamore stands from the Carpathians, have revealed the ecological-floristic distinctiveness of two groups: forest communities from the montane belt that include more orophilous species (Abies alba, Polystichum aculeatum, Campanula patula ssp. abietina), and analogous communities from the hilly belt that differentiate from the former through the occurrence of hornbeam (Carpinus betulus), small-leaved lime (Tilia cordata) and some subthermophilous species (Cornus mas, Arabis turrita). The montane mixed (ash-)sycamore stands do not fit within the current forest typology, and therefore a new zonal-altitudinal variant of the 3418 forest ecosystem type (montane ash-sycamore stand, highly and medium productive, with mull or mull-moder, on eubasic brown soils, excessively moisturised in bottom horizons, with Phyllitis-Lunaria) have been proposed, along with a redefinition of the 0311 forest type whose new denomination is 'montane Wych elm-sycamore stand'. Under similar habitat conditions, the vascular plant diversity and community equitability are conspicuously higher in the ash-sycamore stand than in the adjacent spruce plantation (control). These patterns are undoubtedly related to lower medium indicator values of species of soil moisture and acidity calculated in the spruce plantation than their counterparts in the deciduous stand. This suggests a "xerophytisation" and, especially, an acidification of the upper soil horizon. In the context of spruce plantation in formerly deciduous stands, a stringent conservation and restoration of ash-sycamore communities is needed, as they are rare, occupying small areas, having a high vascular plant diversity and plaing the role of refugia for many forest herbs (Carpathian endemics included).
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