Abstract:

The purpose of the study is to reveal the change trend of woody plants’ phenophase and its response to climate change in the forest-pasture ecotone, and provide meteorological reference for guiding the ecological restoration projects of sand fixation and wind prevention. The phenophase observation data of three kinds of woody plants, Ulmus pumila, Populus simonii Carr and Syringa oblate, and simultaneous meteorological data from Ewenki meteorological experimental station in Inner Mongolia from 1994 to 2019 were used to analyze the influence of climate change on the phenophase of woody plants in the forest-pasture ecotone at the western foot of the Great Khingan Mountains by linear tendency estimation, Pearson correlation coefficient, scatter diagram and other methods. The results showed that in the 26 years, the temperature increased significantly in the plant growing season in this region, and the change trend of precipitation was not obvious. The flowering period of Ulmus pumila, Populus simonii Carr and Syringa oblate was earlier, and the late abscission period was postponed by 9.6, 7.5, and 8.5 d every 10 years, respectively. The growing season was prolonged significantly, and the average growing season was 160-164 d. The air temperature was the key meteorological factor affecting the flowering period in spring and the late abscission period in autumn. The advanced flowering period of the three woody plants had a significantly negative correlation with the rise of temperature in spring, and the postponing of the late abscission period was significantly and positively correlated with the rise of temperature. In conclusion, under the background of climate warming, the earlier flowering period and the delayed late abscission period of the three woody plants have been observed, and the growth period is extended. The postponing days of the late abscission period are more than the earlier days of the flowering period, indicating that climate change has a more obvious impact on the late abscission period of woody plants, and the late abscission period has a greater contribution to the extension of the growing season. The phenophase change of woody plants is mainly influenced by temperature and has little correlation with precipitation in the forest-pasture ecotone at the western foot of the Great Khingan Mountains.

Key words: the western foot of the Great Khingan Mountains, climate change, woody plants, phenophase, correlation analysis