Studying spatial patterns in the forest of Mabura Hill in Guyana, Hans ter Steege, former Tropenbos-Guyana Team-Leader, developed a methodology to measure light conditions using hemispherical photographs.
Light conditions play a crucial role in forest ecology but light measurements are either very expensive or time consuming. In an attempt to tackle these problems, ter Steege designed the computer programme HEMIPHOT that enables the computerised interpretation of light conditions from hemispherical photographs.
The HEMIPHOT programme was developed to provide a user-friendly menu-driven programme with standard input files, and which has ample applicability for hemispherical photographs.
The publications describes how photographs are taken, the scanning of the images to make data sets which can be processed by computer, and how the data are analysed. HEMIPHOT calculates vegetation cover, the direct and diffuse light on both horizontal and inclined surfaces, the leaf area index, and the mean leaf angle and gap size. The publication is a valuable tool in assessing light conditions in tropical rain forests.
Also a Windows version has been developed, called WINPHOT, and published as Tropenbos-Guyana report.