Articles

Étude du rapport entre l'éclairement relatif sous forêt et l'éclairement lumineux incident en phénophase feuillée

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Abstract

The relation between the relative light intensity in a forest  stand and the absolute light intensity above the canopy during the growing  period - In the research center of Virelles (mixed  oak forest) the relation between the relative light intensity and the  absolute incident light intensity was studied.     Only for the light intensity values measured on the real noon, a  mathematical relation was found and this for the growing periods 1965 and  1966. With the decrease of the light intensity in the open, the relative  light intensity increases.     For an identical change of the incident light intensity, the variation of  the relative transmission becomes smaller,   as the crown contact becomes more intense.     The relative light intensity under the canopy, during an ideal day of the  clear weather type, is a function of the sun height and at the same time of  the absolute light intensity in the open.    A measure for the mean relative light intensity of some day can be given by  instantaneous measurements of the relative light intensity, only during the  real noon period.     The found relation may be explained by the fact that direct incident light  is more reflected by the canopy than diffuse light.

How to Cite:

Vyncke, G., (1969) “Étude du rapport entre l'éclairement relatif sous forêt et l'éclairement lumineux incident en phénophase feuillée”, Silva Gandavensis 16. doi: https://doi.org/10.21825/sg.v16i0.1005