New method of dendro-chronology based on R2V and AutoCAD and its application in the mountainous area of northern Hebei province

Taking advantage of the vectorization function of Able Software R2V and measuring function of AutoCAD respectively, a new method to measure tree-ring is put forward, which has been used to measure the tree-ring diameter width of the elm(Ulmus pumila)distributed extensively in the mountainous area of northern Hebei province, and to try the reconstruction of past climates series. The conclusion demonstrates that average temperature and the total precipitation from May to September have positive correlation to the tree-ring indexes and the correlation coefficient are 0.597(α<0.05) and 0.695(α<0.05) respectively. According to these datum, a transformation equation of average air temperature and the total precipitation from May to September was build up. Finally, the average air temperatures and total precipitation from May to September of the 16 years (from 1940 to 1955) in the mountainous area of northern Hebei have been reconstructed.