M. A. Antunes, E. A. Walter-shea, and M. A. Mesearch, Test of an extended mathematical approach to calculate maize leaf area index and leaf angle distribution, Agricultural and Forest Meteorology, vol.108, issue.1, pp.45-53, 2001.
DOI : 10.1016/S0168-1923(01)00219-2

D. Baldocchi and S. Collineau, The physical nature of solar radiation in heterogeneous canopies: spatial and temporal attributes Exploitation of Environmental Heterogeneity by Plants: Ecophysiological Processes Above-and Belowground, pp.21-71, 1994.

J. C. Calvet, J. Noilhan, J. Roujean, P. Bessemoulin, M. Cabelguenne et al., An interactive vegetation SVAT model tested against data from six contrasting sites, Agricultural and Forest Meteorology, vol.92, issue.2, pp.73-95, 1998.
DOI : 10.1016/S0168-1923(98)00091-4

G. S. Campbell, Extinction coefficients for radiation in plant canopies calculated using an ellipsoidal inclination angle distribution, Agricultural and Forest Meteorology, vol.36, issue.4, pp.317-321, 1986.
DOI : 10.1016/0168-1923(86)90010-9

G. S. Campbell, Derivation of an angle density function for canopies with ellipsoidal leaf angle distributions, Agricultural and Forest Meteorology, vol.49, issue.3, pp.173-176, 1990.
DOI : 10.1016/0168-1923(90)90030-A

J. M. Chen, Optically-based methods for measuring seasonal variation of leaf area index in boreal conifer stands, Agricultural and Forest Meteorology, vol.80, issue.2-4, pp.135-163, 1996.
DOI : 10.1016/0168-1923(95)02291-0

J. M. Chen and T. A. Black, Measuring leaf area index of plant canopies with branch architecture, Agricultural and Forest Meteorology, vol.57, issue.1-3, pp.1-12, 1991.
DOI : 10.1016/0168-1923(91)90074-Z

J. M. Chen and T. A. Black, Defining leaf area index for non-flat leaves, Plant, Cell and Environment, vol.7, issue.4, pp.421-429, 1992.
DOI : 10.1016/0168-1923(91)90062-U

J. M. Chen and J. Cihlar, Plant canopy gap-size analysis theory for improving optical measurements of leaf-area index, Applied Optics, vol.34, issue.27, pp.6211-6222, 1995.
DOI : 10.1364/AO.34.006211

J. M. Chen and J. Cihlar, Quantifying the effect of canopy architecture on optical measurements of leaf area index using two gap size analysis methods, IEEE Transactions on Geoscience and Remote Sensing, vol.33, issue.3, pp.777-787, 1995.
DOI : 10.1109/36.387593

B. Combal, F. Baret, and M. Weiss, Improving canopy variables estimation from remote sensing data by exploiting ancillary information. Case study on sugar beet canopies, Agronomie, vol.22, issue.2, pp.205-215, 2002.
DOI : 10.1051/agro:2002008

M. Españ-a, F. Baret, F. Ariè-s, B. Andrieu, and M. Chelle, Radiative transfer sensitivity to the accuracy of canopy structure description. The case of a maize canopy, Agronomie, vol.19, issue.3-4, pp.3-4, 1999.
DOI : 10.1051/agro:19990305

G. W. Frazer, C. D. Canham, and K. P. Lertzman, Gap Light Analyzer (GLA), Version 2.0: Imaging software to extract canopy structure and gap light transmission indices from true-color fisheye photographs, users manual and program documentation, British Columbia and the Institute of Ecosystem Studies, 1999.

G. W. Frazer, R. A. Fournier, J. A. Trofymow, and R. J. Hall, A comparison of digital and fisheye photography for analysis, 2001.

G. W. Frazer, J. A. Trofymow, and K. P. Lertzman, Canopy openness and leaf area in chronosequences of coastal temperate rainforests, Canadian Journal of Forest Research, vol.30, issue.2, pp.239-256, 2001.
DOI : 10.1139/x99-201

S. T. Gower, C. J. Kucharik, and J. M. Norman, Direct and Indirect Estimation of Leaf Area Index, fAPAR, and Net Primary Production of Terrestrial Ecosystems, Remote Sensing of Environment, vol.70, issue.1, pp.29-51, 1999.
DOI : 10.1016/S0034-4257(99)00056-5

I. Jonckheere, . Fleck, K. Nackaerts, B. Muys, and P. Coppin, Assessment of automatic gap fraction estimation of forests from digital hemispherical photography, Agricultural and Forest Meteorology, vol.132, issue.1-2, pp.96-114, 2005.
DOI : 10.1016/j.agrformet.2005.06.003

I. Jonckheere, . Fleck, K. Nackaerts, B. Muys, P. Coppin et al., Review of methods for in situ leaf area index determination, Agricultural and Forest Meteorology, vol.121, issue.1-2, pp.19-35, 2004.
DOI : 10.1016/j.agrformet.2003.08.027

C. J. Kucharik, J. M. Norman, L. M. Murdock, and S. T. Gower, Characterizing canopy nonrandomness with a multiband vegetation imager (MVI), Journal of Geophysical Research: Atmospheres, vol.83, issue.1, pp.29455-29473, 1997.
DOI : 10.1029/97JD01175

R. Kussner and R. Mosandl, Comparison of direct and indirect estimation of leaf area index in mature Norway spruce stands of eastern Germany, Canadian Journal of Forest Research, vol.30, issue.3, pp.440-447, 2000.
DOI : 10.1139/x99-227

A. R. Lang and Y. Xiang, Estimation of leaf area index from transmition of direct sunlight in discontinuous canopies, 1986.

S. G. Leblanc, J. M. Chen, and M. Kwong, Tracing Radiation and Architecture of Canopies, TRAC MANUAL, Version 2.1. Natural Resources Canada, pp.1-25, 2002.

S. G. Leblanc, J. M. Chen, R. Fernandes, D. W. Deering, and A. Conley, Methodology comparison for canopy structure parameters extraction from digital hemispherical photography in boreal forests, Agricultural and Forest Meteorology, vol.129, issue.3-4, pp.187-207, 2005.
DOI : 10.1016/j.agrformet.2004.09.006

R. Lemeur and B. L. Blad, A critical review of light models for estimating the shortwave radiation regime of plant canopies, Agricultural Meteorology, vol.14, issue.1-2, pp.255-286, 1974.
DOI : 10.1016/0002-1571(74)90024-7

P. E. Levy and P. G. Jarvis, Direct and indirect measurements of LAI in millet and fallow vegetation in HAPEX-Sahel, Agricultural and Forest Meteorology, vol.97, issue.3, pp.199-212, 1999.
DOI : 10.1016/S0168-1923(98)00092-6

C. Macfarlane, M. Hoffman, D. Eamus, N. Kerp, S. Higginson et al., Estimation of leaf area index in eucalpyt forest using digital photography, Agric. For. Meteorol, vol.143, pp.3-4, 2007.

J. B. Miller, A formula for average foliage density, Australian Journal of Botany, vol.15, issue.1, pp.141-144, 1967.
DOI : 10.1071/BT9670141

M. Monsi and T. Saeki, U ¨ ber den Lichtfaktor in den Pflanzengesellschaften und seine Bedeutung fü r die Stoffproduktion, Jpn. J. Bot, vol.14, pp.22-52, 1953.

J. Morisette, F. Baret, J. L. Privette, R. B. Myneni, J. Nickeson et al., Validation of global moderate-resolution LAI products: a framework proposed within the CEOS land product validation subgroup, IEEE Transactions on Geoscience and Remote Sensing, vol.44, issue.7, pp.1804-1817, 2006.
DOI : 10.1109/TGRS.2006.872529

S. Muusche, R. Samson, L. Nachtergale, A. De-schrijver, R. Lemeur et al., A comparison of optical and direct methods for monitoring the seasonal dynamics of leaf area index in deciduous forest stands. Silva Fenn, pp.373-384, 2001.

H. H. Neumann, G. D. Den-hartog, and R. H. Shaw, Leaf area measurements based on hemispheric photographs and leaf-litter collection in a deciduous forest during autumn leaf-fall, Agricultural and Forest Meteorology, vol.45, issue.3-4, pp.325-345, 1989.
DOI : 10.1016/0168-1923(89)90052-X

T. Nilson, A theoretical analysis of the frequency of gaps in plant stands, Agricultural Meteorology, vol.8, pp.25-38, 1971.
DOI : 10.1016/0002-1571(71)90092-6

P. M. Rich, Characterizing plant canopies with hemispherical photographs, Remote Sensing Reviews, vol.114, issue.1, pp.13-29, 1990.
DOI : 10.1007/BF00384537

J. Ross, The Radiation Regime and Architecture of Plant Stands. The Hague, 1981.

J. P. Sellers, R. E. Dickinson, D. A. Randall, A. K. Betts, F. G. Dall et al., Modeling the Exchanges of Energy, Water, and Carbon Between Continents and the Atmosphere, Modeling the exchanges of energy, water, and carbon between continents and the atmosphere, pp.502-509, 1997.
DOI : 10.1126/science.275.5299.502

H. Spath, Cluster Dissection and Analysis: Theory, FORTRAN Programs, Examples, 1985.

J. M. Walter, CIMES. A Package of Programs for the Assessment of Canopy Geometry through Hemispherical Photographs. Manual, 1989.

Y. P. Wang and P. G. Jarvis, Mean leaf angles for the ellipsoidal inclination angle distribution, Agricultural and Forest Meteorology, vol.43, issue.3-4, pp.319-321, 1988.
DOI : 10.1016/0168-1923(88)90057-3

Y. P. Wang and R. Leuning, A two-leaf model for canopy conductance, photosynthesis and partitioning of available energy I:, Agricultural and Forest Meteorology, vol.91, issue.1-2, pp.89-111, 1998.
DOI : 10.1016/S0168-1923(98)00061-6

J. Warren-wilson, Estimation of foliage denseness and foliage angle by inclined point quadrats, Australian Journal of Botany, vol.11, issue.1, pp.95-105, 1963.
DOI : 10.1071/BT9630095

M. Weiss, F. Baret, G. J. Smith, I. Jonckheere, and P. Coppin, Review of methods for in situ leaf area index (LAI) determination, Agricultural and Forest Meteorology, vol.121, issue.1-2, pp.37-53, 2004.
DOI : 10.1016/j.agrformet.2003.08.001

J. M. Welles, Some indirect methods of estimating canopy structure, Remote Sensing Reviews, vol.2, issue.1, pp.31-43, 1990.
DOI : 10.1111/j.1469-8137.1960.tb06195.x

J. M. Welles and J. M. Norman, Instrument for Indirect Measurement of Canopy Architecture, Agronomy Journal, vol.83, issue.5, pp.818-825, 1991.
DOI : 10.2134/agronj1991.00021962008300050009x

Y. Zhang, J. M. Chen, and J. R. Miller, Determining digital hemispherical photograph exposure for leaf area index estimation, Agricultural and Forest Meteorology, vol.133, issue.1-4, pp.166-181, 2005.
DOI : 10.1016/j.agrformet.2005.09.009