[Anderson, M.C. 1964. Studies of the woodland light climate. I. The photographic computation of light condition. - Journal of Ecology, 52, 27-41.]Search in Google Scholar
[Atkins, W.R.G, Poole, H.H, Stanbury, F.A. 1937. The measurement of the intensity and the colour of the light in woods by means fo emission and rectifi er photoelectric cells. - Proceedings of the Royal Society of London, 121, 427-450.]Search in Google Scholar
[Beerling, D. 2012. The Emerald Planet. How plants changed Earth’s history. (Smaragdplaneet. Kuidas taimed on muutnud Maa ajalugu). Tallinn, Kirjastus Varrak. 352 pp. (Translation into Estonian).]Search in Google Scholar
[Cescatti, A. 2007. Indirect estimates of canopy gap fraction based on the linear conversion of hemispherical photographs - Methodology and comparison with standard thresholding techniques. - Agricultural and Forest Meteorology, 143(1-2), 1-12.]Search in Google Scholar
[CIE, 2004. ISO 15469:2004/CIE S 011:2003. Joint ISO/ CIE standard: spatial distribution of daylight - CIE standard general sky.]Search in Google Scholar
[Coffi n, D. 2013. Decoding raw digital photos in Linux. [WWW document]. - URL http://www.cybercom.net/~dcoffin/dcraw/ [Accessed 10 April 2014].]Search in Google Scholar
[Evans, G.C., Coombe, D.E. 1959. Hemispherical and woodland canopy photography and the light climate. - Journal of Ecology, 47, 123-144.]Search in Google Scholar
[Frazer, G.W., Canham, C.D., Lertzman, K.P. 1999.]Search in Google Scholar
[Gap Light Analyzer (GLA), Version 2.0: Imaging software to extract canopy structure and gap light transmission indices from true-colour fi sheye photographs, user’s manual and program documentation. Simon Fraser University, Burnaby, British Columbia; The Institute of Ecosystem Studies, Millbrook, New York.]Search in Google Scholar
[Hordo, M., Kiviste, A., Sims, A. 2006. The network of permanent sample plots for forest growth in Estonia. - Nagel, J. (ed.). Deutscher Verband Forstlicher Forschungsanstalten: DVFFA - Sektion Ertragskunde, Staufen, May 29-31, 2006, Germany, 115-121.]Search in Google Scholar
[Jonckheere, I., Fleck, S., Nackaerts, K., Muys, B., Coppin, P., Weiss, M., Baret, F. 2004. Review of methods for in situ leaf area index determination Part I. Theories, sensors and hemispherical photography. - Agricultural and Forest Meteorology, 121, 19-35.]Search in Google Scholar
[Jonckheere, I., Nackaerts, K., Muys, B., Coppin, P. 2005. Assessment of automatic grap fraction estimation of forests from digital hemispherical photography. - Agricultural and Forest Meteorology, 132, 96-114.]Search in Google Scholar
[Inoue, A., Yamamoto, K., Mizoue, N., Kawahara, Y. 2004. Effects of image quality, size and camera type on forest light environment estimates using digital hemispherical photography. - Agricultural and Forest Meteorology, 126(1-2), 89-97.]Search in Google Scholar
[Kittler, R. 1994. Some qualities of scattering functions defi ning sky radiance distributions. - Solar Energy, 53(6), 511-516.]Search in Google Scholar
[Kuusk, A., Nilson, T., Paas, M. 2002. Angular distribution of radiation beneath forest canopies using a CCD-radiometer. - Agricultural and Forest Meteorology, 110(4), 259-273.]Search in Google Scholar
[Lang, M., Kuusk, A., Mõttus, M., Rautiainen, M., Nilson, T. 2010. Canopy gap fraction estimation from digital hemispherical images using sky radiance models and a linear conversion method. - Agricultural and Forest Meteorology, 150(1), 20-29.]Search in Google Scholar
[Lclevy. 2013. Understanding what is stored in a Canon RAW .CR2 fi le, How and why (.CR2 fi les are produced by Canon EOS digital cameras since 2004). Version 0.72 (August 30th, 2013). [WWW document]. - URL http://lclevy.free.fr/cr2/index.html#wb [Accessed 10 April 2014].]Search in Google Scholar
[Lebourgeois, V., Bégué, A., Labbé, S., Mallavan, B., Prévot, L., Roux, B. 2008. Can Commercial Digital Cameras Be Used as Multispectral Sensors? A Crop Monitoring Test. - Sensors, 8, 7300-7322.10.3390/s8117300378744627873930]Search in Google Scholar
[Leblanc, S.G., Chen, J.M., Fernandes, R., Deering, D.W., Conley, A. 2005. Methodology comparison for canopy structure parameters extraction from digital hemispherical photography in boreal forests. - Agricultural and Forest Meteorology, 129(3-4) 187-207.]Search in Google Scholar
[Leblanc, S.G. 2008. DHP-TRACWin Manual. Natural Recources Canada, Canada Centre for Remote Sensing. 29 pp.10.4095/327594]Search in Google Scholar
[Lõhmus, E. 2004. Eesti metsakasvukohatüübid. (Forest site types in Estonia). Tartu, Eesti Loodusfoto. 80 pp. (In Estonian).]Search in Google Scholar
[Macfarlane, C., Michael Coote, M., White, D.A., Adams, M.A. 2000. Photographic exposure affects indirect estimation of leaf area in plantations of Eucalyptus globulus Labill. - Agricultural and Forest Meteorology, 100(2-3), 155-168.]Search in Google Scholar
[Macfarlane, C., Hoffman, M., Eamus, D., Kerp, N., Higginson, S., McMurtrie, R., Adams, M. 2007a. Estimation of leaf area index in eucalypt forest using digital photography. - Agricultural and Forest Meteorology, 143(3-4), 176-188.]Search in Google Scholar
[Macfarlane, C., Grigg, A., Evangelista, C. 2007b. Estimating forest leaf area using cover and fullframe fi sheye photography: Thinking inside the circle. - Agricultural and Forest Meteorology, 146 (1-2), 1-12.]Search in Google Scholar
[Manninen, T., Korhonen, L., Voipio, P., Lahtinen, P., Stenberg, P. 2009. Leaf area index (LAI) estimation of boreal forest using wide optics airborne winter photos. - Remote Sensing, 1, 1380-1394.]Search in Google Scholar
[Niinemets, Ü., Ellsworth, D.S., Lukjanova, A., Tobias, M. 2001. Site fertility and the morphological and photosynthetic acclimation of Pinus sylvestris needles to light. - Tree Physiology, 21, 1231-1244.]Search in Google Scholar
[Nilson, T. 1971. A theoretical analysis of the frequency of gaps in plant stands. - Agricultural and Forest Meteorology, 8, 25-28.]Search in Google Scholar
[Nilson, T., Kuusk, A. 2004. Improved algorithm for estimating canopy indices from gap fraction data in forest canopies. - Agricultural and Forest Meteorology, 124(3-4), 157-169.]Search in Google Scholar
[Nobis, M., Hunziker, U. 2005. Automatic thresholding for hemispherical canopy-photographs based on edge detection. - Agricultural and Forest Meteorology, 128, 243-250.]Search in Google Scholar
[Pisek, J., Lang, M., Nilson, T., Korhonen, L., Karu, H. 2011. Comparison of methods for measuring gap size distribution and canopy nonrandomness at Järvselja RAMI (RAdiation transfer Model Intercomparison) test sites. - Agricultural and Forest Meteorology, 151(3), 365-377.]Search in Google Scholar
[Rich, P.M. 1990. Characterizing plant canopies with hemispherical photographs. - Remote Sensing Reviews, 5, 13-29.]Search in Google Scholar
[Ryu, Y., Sonnentag, O., Nilson, T., Vargas, R., Kobayashi, H., Wenk, R., Baldocchi, D.D. 2010. How to quantify tree leaf area index in an open savanna ecosystem: A multi-instrument and multi-model approach. - Agricultural and Forest Meteorology, 150(1), 63-76.]Search in Google Scholar
[Song, G.-Z. M., Doley, D., Yates, D., Chao, K.-J., Hsieh, C.-F. 2014. Improving accuracy of canopy hemispherical photography by a constant threshold value derived from an unobscured overcast sky. - Canadian Journ al of Forest Research, 44, 17-27.]Search in Google Scholar
[Schleppi, P., Conedera, M., Sedivy, I., Thimonier, A. 2007. Correcting non-linearity and slope effects in the estimation of the leaf area index of forests from hemispherical photographs. - Agricultural and Forest Meteorology, 144, 236-242.]Search in Google Scholar
[Tooming, H. 1977. Солнечная радиация и форми- рование урожая. (Solar radiation and crop yield production). Leningrad, Gidrometeoizdat. 200 pp. (In Russian).]Search in Google Scholar
[Walter, J.-M. 2009. CIMES-FISHEYE - hemispherical photography of forest canopies. [WWW document]. - URL http://jmnw.free.fr [Accessed 10 April 2014]. Université de Strasbourg, Faculté des Sciences de la Vie, Institut de Botanique, 28 Rue Goethe, 67083 Strasbourg Cedex France.]Search in Google Scholar
[Watson, D.J. 1947. Comparative physiological studies in the growth of fi eld crops. I. Variation in net assimilation rate and leaf area between species and varieties, and within and between years. - Annals of Botany, 11, 41-76.]Search in Google Scholar
[Weiss, M. 2013. Welcome to the CAN-EYE web site. [WWW document]. - URL https://www4.paca.inra.fr/can-eye [Accessed 10 April 2014].]Search in Google Scholar
[Welles, J.M., Norman, J.M. 1991. Instrument for indirect measurement of canopy architecture. - Agronomy Journal, 83, 818-825.]Search in Google Scholar
[Wilson, J.W. 1960. Inclined point quadrats. - New Phytologist, 59, 1-7. ]Search in Google Scholar