Measuring Vegetation Changes on Fixed Quadrats by Vertical Ground Stereophotography

Abstract

A photographic technique for recording changes in vegetation on small fixed quadrats has been modified and improved. Two 35 mm cameras fired simultaneously are used instead of one to take stereophotographs. Transparencies are viewed directly by transmitted light under a zoom stereoscope and plant cover measured by point counts made on the photographs with the aid of a counter connected to an electrically operated stage. Assessment of species composition and herbage weight is also possible from the photographs which themselves form a permanent record of vegetation on the quadrats.