Estimating leaf inclination and G-function from leveled digital camera photography in broadleaf canopies
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The effectiveness of using leveled digital camera for measuring leaf inclination angles was investigated in this study as an inexpensive and convenient alternative to existing approaches. The new method is validated with manual leaf angle measurements for various broadleaf tree species common to hemi-boreal region of Estonia and the tropical forests of Hawai’i Islands. The acquired leaf angle distributions suggest that planophile case might be more appropriate than the commonly assumed spherical as the general approximation of leaf orientation while modeling the radiation transmission through the canopies of (hemi)-boreal broadleaf stands. However, direct leaf inclination measurements should be obtained whenever possible, as there will always exist a large variety of leaf orientation, both among different species and in the space–time domain within a single species. The camera method tested in this study provides a new robust and affordable tool to obtain this information.
KeywordsLeaf inclination angle G-function Gap fraction Digital photography
This study was supported by the funding from FP7-REGPOT, No. 204727 EstSpacE. We would like to thank Joel Kuusk at Tartu Observatory for the clinometer; Dr. Mait Lang kindly provided his Canon EOS 5D camera. We thank Dr. Tiit Nilson for fruitful discussions. Comments by two anonymous reviewers helped to improve the manuscript.
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