Estimating Morphological Parameters of Tamarix by Digital Hemispherical Image in the Lower Reaches of Heihe River, Northwest China

Tamarix is one kind of shrub which is widespread species in sand and saline land in arid and semi-arid regions. Tamarix has been paid more attentions for its unique physiological and ecological features, and important socioeconomic effects. In order to study the biomass and growth status of Tamarix, we need to measure the morphological parameters (e.g. height, perimeter of canopy). However, there has been a lack of effective methods for quantitative estimation of the parameters. It is usual to measure the morphological parameters of Tamarix using tapes and other ancillary tools. But the traditional methods are low in efficiency and accuracy, and acquire less parameters. The hemispherical image method has thus been used [1]. The method is widely accepted with the development of the digital camera and a large number of image processing softwares. The photogrammetry can easily obtain the surface features of shrub. And instruments are convenient to operate in field survey. Therefore we used the photogrammetry to obtain the morphological parameters of Tamarix. The aim of this study is to establish a convenient, fast and high accuracy method for estimating morphological parameters of Tamarix with digital hemispherical images.