Sg. Chen et al., A FRACTAL-BASED POPULUS CANOPY STRUCTURE MODEL FOR THE CALCULATION OFLIGHT INTERCEPTION, Forest ecology and management, 69(1-3), 1994, pp. 97-110
A canopy light-interception model for a Populus stand is presented. To
model the canopy, a new approach based on fractal geometry is used, w
hich allows the simulation of the three-dimensional (3D) radiation reg
ime in a heterogeneous canopy. Based on both the fractal approach and
a set of growth and development rules of Populus trees grown under sho
rt-rotation intensive culture, a 3D crown architecture submodel is dev
eloped to generate the individual tree frames of a stand. The temporal
and spatial variations in leaf area are taken into account in a leaf
dynamics submodel. Coupling of the leaf model with the tree frame mode
l results in a 3D leaf distribution in the canopy. Diffuse and direct
light distribution are computed for each leaf layer using a 3D radiati
ve transfer model. The intercepted light of sunlit and shaded leaves i
n each layer is summed to find the instantaneous light interception by
the canopy. The daily and seasonal total canopy light interception ar
e estimated using the Gaussian numerical integration over the daylight
period and the growing season, respectively.