Modeling the gap probability of a discontinuous vegetation canopy

A model is presented for the gap probability of a discontinuous vegetation canopy, such as forest, savanna, or shrubland. The case in which the distribution of individual canopy sizes and shapes is known and individual canopies are randomly distributed but do not overlap, and the case in which the canopies to intersect and/or overlap such that foliage density remains constant with the overlap area are both considered, although an exact solution is provided only for the latter. A comparison of modeled gap probabilities with observed gap probabilities for a Maryland (US) pine stand (as taken from the literature) shows good agreement for zenith angles of illumination up to about 45 degrees . Above 45 degrees , the fit worsens, presumably because the horizontal branch structure of the pine canopy is less attenuating as the illumination angle approaches the horizon. >

[1]  J. A. Ferguson.  A comparison of two planting systems in orchards as regards the amount of radiation intercepted by the trees. , 1960 .

[2]  D S Kimes,et al.  Radiative transfer model for heterogeneous 3-D scenes. , 1982, Applied optics.

[3]  J. W. Palmer,et al.  Interception of Light by Model Hedgerow Orchards in Relation to Latitude, Time of Year and Hedgerow Configuration and Orientation , 1972 .

[4]  D. Charles-Edwards,et al.  Interception of Diffuse and Direct-beam Radiation by a Hedgerow Apple Orchard , 1976 .

[5]  A. Strahler,et al.  Geometric-Optical Bidirectional Reflectance Modeling of a Conifer Forest Canopy , 1986, IEEE Transactions on Geoscience and Remote Sensing.

[6]  J. W. Palmer,et al.  Diurnal Light Interception and a Computer Model of Light Interception by Hedgerow Apple Orchards , 1977 .

[7]  G. Suits.  The calculation of the directional reflectance of a vegetative canopy , 1971 .

[8]  G. Ailam.  Moments of coverage and coverage spaces , 1966, Journal of Applied Probability.

[9]  T. Nilson.  A theoretical analysis of the frequency of gaps in plant stands , 1971 .

[10]  Ross Nelson,et al.  Directional Reflectance Distributions of a Hardwood and Pine Forest Canopy , 1986, IEEE Transactions on Geoscience and Remote Sensing.

[11]  J. Norman,et al.  Radiative Transfer in an Array of Canopies1 , 1983 .

[12]  J. W. Palmer,et al.  A Simple Model of Light Transmission and Interception by Discontinuous Canopies , 1979 .

[13]  S. Idso,et al.  Light relations in plant canopies. , 1970, Applied optics.

[14]  A. Strahler,et al.  Geometric-Optical Modeling of a Conifer Forest Canopy , 1985, IEEE Transactions on Geoscience and Remote Sensing.

[15]  D. Jupp,et al.  Interpretation of vegetation structure in Landsat MSS imagery: a case study in disturbed semi-arid eucalypt woodlands. Part 2. Model-based analysis , 1986 .