Beskydy 2013, 6, 53-58
Importance of light conditions for the height growth of underplatings in Norway spruce stands in the Oravské Beskydy Mts.
The study analyses the relationships between the components of relative irradiance and density of parent Norway spruce stand as well as the impact of light on height growth and crown architecture of beech and fir underplantings and natural regeneration of spruce. We observed three variants of regeneration: fir underplanting, beech underplanting and spruce natural regeneration. For each variant three circular research plots with the size 500 m2 were established. To determine the intensity of relative irradiance 15 hemispherical photographs in the height of 1.5 m were taken for each variant. The analysis confirmed a significant relationship only between indirect site factor (ISF) and basal area and partly stem number of parent stand. There is almost no influence of spruce overstorey density (within the observed range of basal area and stem number) on the values of total site factor (TSF) and its main component direct site factor (DSF). The relevant predictor for the height increments of underplanted saplings is ISF. Relationship between TSF and height increment is weak. Apical dominance ratio (ADR) that was used to characterize crown architecture is significantly correlated with ISF only for beech and fir. In the case of spruce, increase of light intensity in the observed range does not lead to a significant change of saplings crown architecture.
Keywords
Norway spruce, silver fir, common beech, underplantings, stand conversion, hemispherical photographs, canopy cover.
