Vol. 53 (2), 114–122

Folia Forestalia Polonica, series A, 2011, Vol. 53 (2), 114–122

Net radiation of mountain cultivated Norway spruce [Picea abies (L.) Karst.] stand: evaluation of shortand long-wave radiation ratio

Irena Marková¹ and Michal V. Marek^1,2
¹ Mendel University in Brno, Faculty of Forestry and Wood Technology, Department of Forest Ecology, Zemědělská 3,
613 00 Brno, Czech Republic, phone: +420 545 134 189, e-mail: markova@mendelu.cz
² Academy of Sciences, Global Change Research Centre – CzechGlobe, Laboratory of Plant Ecological Physiology,
Bělidla 986/4a, 603 00 Brno, Czech Republic

Abstract
The radiation exchange drives the plant ecosystems energy balance and provides the energy for photosynthesis, transpiration and plant growth. The investigation on net radiation and its component during vegetation season in relation to the clearness index and sun elevation in a cultivated 31-year-old mountain spruce [Picea abies (L.) Karst.] stand is presented. Downward short-wave radiation – S_d (incident on the spruce stand was the main part of the short-wave radiation balance during the whole growing season (April–October) 2008. The S_d amount is seasonally variable factor determined by the duration of solar shine and the atmosphere transmissivity. Obtained value of net radiation (R_n) and downward short-wave radiation (S_d) ratio amounts to 0.61 on average during the growing season 2008 documenting the importance of the downward short-wave radiation in the net radiation of investigated spruce stand.

Key words
downward short- and long-wave radiation, upward short- and long-wave radiation, sun elevation, clearness index