Understory Light Environment of Canopy Tree Species in Urban Green Land

Abstract: To give some scientific references for the multi-level configuration of plant community in urban green land, especially for how to choose undergrowth plants which have different light habits, this research investigated the canopy structure and determined understory light environment of 23 canopy tree species which are mostly applied in urban green land in Guangdong province using hemispherical photography. The results showed that understory light environment was influenced by canopy structure significantly and there were significant positive correlation (P < 0.001) between CO and TransDir, TransDif and TransTol, with the correlation coefficient (r) of 0.88, 0.95 and 0.91, respectively; and a extremely significant negative correlation between CO and LAI (r = -0.63; P < 0.001). Hemispherical photography has lots of advantages which are convenient, rapid, practical and accurate. It could not only monitor canopy structure but also determine single tree and canopy tree species which the canopy was broken. This method is supposed to contribute to quantitative research on understory light environment and is essential for scientific research and popularizing in the development of urban garden.