Transmittance of young Norway spruce stand canopy for photosynthetically active radiation during the growing season

Abstract

MARKOVÁ IRENA, KUBÁSEK JIŘÍ: Transmittance of young Norway spruce stand canopy for photosynthetically active radiation during the growing season. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 1, pp. 129-135 Analysis of transmittance of young Norway spruce stand canopy for photosynthetically active radiation (PAR) was made at the study site of Bílý Kříž (the Moravian-Silesian Beskids Mts., the Czech Republic) at diff erent sky conditions during the growing season in 2010. For the description of PAR transmittance diff erent phenological phases of the spruce stand development in clear and overcast days were chosen. The mean daily PAR transmittance of the spruce canopy was signifi cantly higher in overcast days compared with clear ones. Diff use PAR thus penetrated into lower parts of the canopy more effi ciently than direct one. PAR transmittance of young Norway spruce stand canopy was diff erent in individual phenological phases of the spruce stand canopy which was caused by changes in the stand structure during the growing season. Thus monitoring of transmittance of young Norway spruce stand canopy for PAR can help to describe the development of spruce stand canopy. overcast and clear days, phonological phases