Measuring the luminous and spectral characteristics of light transmitted through a beech tree indoors: a case study

This paper examines the impact of a deciduous Beech tree on indoor daylight quality in a room where the window is fully obscured by the tree. Trees, with their complex geometries, act as fenestration systems that modulate the quantities and spectral characteristics of daylight. The Beech tree's geometry and leaf colour change with the seasons, losing leaves in winter and changing leaf colour from summer to autumn. To capture these variations and understand how a Beech tree modulates daylight, the study measures luminance, spectral irradiance, and spectral radiance across spring, summer, winter, and autumn. Findings illustrate how the spectral and photometric qualities of daylight change with the tree's seasonal variations.