The application of digital photographic method in the forest has shown great potential for improving the accuracy and efficiency. Image acquired with acommercially available digital camera were used to make measurements on 10 Platanus orientalis stems. Laser spot was used as scale instead of pole. The laser spot was extracted from the background by the 2-D Otsu algorithm. Error studies showed that the laser spot should be set at 1.3m high to improve the measurement accuracy. The accuracy of this method for measuring diameters at breast height was tested by comparing the results with those obtained from caliper. The comparison showed that the photographic method provided a good assessment of standing tree diameters at breast height and the maximum error was 1.22%.