Light Intensity Measurements in Rain Forest Near Santarem, Brazil

Publisher Website
Google Scholar
Abstract
On August 7, 1954, a series of photometer readings were taken near Monte Alegre, Para, Brazil, in evergreen rain forest at the beginning of the dry season. Observations were made at different heights in the forest, all up 1 tree, from dawn to dusk during 1 day. Despite limitations in the method used, the observations showed that: (a) the ground level series corresponded closely with those obtained by more complex methods by Evans in Nigeria; (b) the density of the second story was the predominant controller both of light intensity and of the fraction of the day during which sunflecks were present within the forest canopy; (c) the shading effect of the emergent canopy is thrown over a considerable area of the neighboring forest as the sun passes round, thus leaving few parts of the second story unshaded, at least during 1 part of the day. The method shows that though the worker in the tropics may have only a simple apparatus, unsuited to this type of work, the results can still be worthwhile.