Relationship between forest canopy and natural regeneration in the subalpine spruce-larch forest (north-east Italy)

Przemysław Szmit

The authors describe the difference between canopy cover (proportion of the forest floor covered by the vertical projection of the tree crowns) and canopy closure (proportion of sky hemisphere obscured by vegetation when viewed from a single point) and the respective ground-based estimation techniques focused on two types of densiometer (GRS tube and spherical). The data collected in the field were used to analyse the relationship between forest canopy and natural regeneration in two subtypes of subalpine larch-spruce forests. The results indicate that in the first subtype characterized by a high fertility and a high canopy cover (around 62%), the level of natural regeneration is low (115 stems per hectare) and it is nearly exclusively composed by spruce [Picea abies (L.) Karst.]. For the second subtype characterized by a low fertility and a medium canopy cover (around 49%) the natural regeneration is rather dense (650 stems per hectare). At last the authors evidence a insignificant difference between the data of forest canopy collected by different ground-based estimation techniques (+0.7% using spherical densiometer compared to using GRS tube densiometer).