[GIS-based measurement of Haloxylon ammodendron tree ring]

Tree ring data is of significance for reconstructing climate and predicting environmental dynamics. In order to accurately measure spacing and other parameters of Haloxylon ammodendron tree ring, we first assigned coordinate system to the scanned H. ammodendron disc PS images based on GIS, and then completed the H. ammodendron tree ring spacing measurement by using ENVI image classification software and GIS measuring tool. The measurement accuracy was proved by WinDENDRO tree ring analysis system. The results showed that there was no significant difference between those two methods (P=0.63), and that the difference of paired mean value was 0.87 μm, indicating that the measured results were accurate and reliable. The constructed method in this study could be used to measure the spacing of H. ammodendron tree ring, which lay the foundation for the automatic measurement of tree ring parameters such as area and perimeter. Our method could replace the current professional tree ring analysis system for some ring parameter measurement. The study would contribute to the dendroclimatology analysis and the investigation on age structure of H. ammodendron population.