Phenological changes of populus simonii and its relationship with meteorological conditions in the Eastern Inner Mongolia

The climate changes during recent 20 -30 a in main animal husbandry stations of Eastern Inner Mongolia and the phenological changes of populus simonii were discussed by the mathematical statistics method. The relationships between the phenological changes of populus simonii and the meteorological conditions were analyzed. The results indicate that the first day (0℃) is ahead, and the last day (0℃) is lagged. The accumulated temperature (0℃) increases obviously. Flower buds opening phase, leave unfolding primary and prevailing phases, and blossoming primary phase in the first half year are ahead, while leave coloring phase, leave falling ending phase and blossoming prevailing phase are put off. Natural phenology of populus simonii is different in different regions of Eastern Inner Mongolia. The phenological phase of populus simonii in the first half year has a negative correlation with air temperature, while that in the second half year has a positive correlation with air temperature. Phenological phase changes of populus simonii are of strong response to air temperature change, and their relationships may be nonlinear. The effects of sunshine and precipitation on phenology phase changes are different because of the difference of the geographical location and the growing phases. Phenological phase changes of populus simonii have not obvious response to precipitation and sunshine.