太阳辐射是树木生长发育所需能量的来源。太阳辐射到达树冠上表面后,受到树冠的吸收、反射、透射作用,使得林冠层内,太阳辐射能的分布,形成其特有的规律。研究杨树无性系苗群体辐射分布特征,对杨树苗圃速生丰产有很大实践意义。太阳辐射由直接辐射与散射组成。由于使用相对日射表测定研究林冠内部太阳直接辐射时对准太阳视面带来的困难,所以,我们用天空辐射表测定的总辐射,研究总辐射 Solar radiation is the source of energy needed for the growth of trees. After the solar radiation reaches the top surface of the canopy, it is absorbed, reflected and transmitted by the canopy, so that the distribution of solar radiation energy in the canopy layer forms its unique law. Research poplar clonal populations of radiation distribution characteristics of poplar nursery fast-growing and have great practical significance. Solar radiation consists of direct radiation and scattering. Since the use of a relative emissometer to determine the alignment of the sun’s visible surface when studying the direct solar radiation inside the canopy is difficult, we used the total radiation measured by the sky radiometer to study the effects of total radiation