Preliminary Studies in Photographic Determination of Tree Shade Capacities

in HortScience
Authors:
Timothy J. GardnerDepartment of Horticulture, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691

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T. Davis SydnorDepartment of Horticulture, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691

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Abstract

Photographs of five fully foliaged shade tree canopies (Acer. rubrum, Gleditsia triacanthos inermis, Gymnocladus dioicus, Pyrus calleryana, and Zelkova serrata) were taken using four film types, 50- and 28-mm lenses, and a range of three f-stops. Photographs of four leafless shade tree canopies (Gleditsia, Gymnocladus, Pyrus, and Zelkova) were taken using three film types and two lenses, at two f-stops. Film densities were determined with a light source and quantum sensor system for negatives of fully foliaged and leafless canopies and correlated with mean percentage of shade measured with a pyranometer. Pan-X film, at the correct f-stop setting, gave the highest correlation to mean percentage of the fully foliaged canopies. The 50-mm lens gave a higher correlation than the 28-mm lenses. Plus-X film, at an f-stop one above the proper setting, gave the highest correlation to mean percentage of shade of the leafless canopy. Plus-X film produced the most consistent results when photographs of the leafless canopy were taken during different days and times of the day. Using a densitometer to measure film density of the negatives gave high correlations to mean percentage of shade of the leafless canopy.

Contributor Notes

Director, Franklin Park Conservatory and Garden Center, 1777 E. Broad St., Columbus, OH 43203.

Associate Professor of Horticulture, 2001 Fyffe Court, Columbus, OH 43210.

Received for publication 9 Apr. 1984. Salaries and research support provided by state and federal funds appropriated to the Ohio Agricultural Research and Development Center, The Ohio State Univ. Journal Article no. 39-84. Taken from a thesis submitted by T.J.G. in partial fulfillment of the MS requirements of The Ohio State Univ. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.

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