Abstract:

In order to reveal the response of four broad-leaved arbors to climate change, we studied relationships between interannual variations of air temperature and various phenophases (i.e., seasonal biological events) of broad-leaved arbors species (Betula platyphylla, Juglans mandshurica, Ulmus pumila and Morus alba) in the Harbin, based on meteorological data from 1951-2008 and phenological data from 1963-2008. Results showed that the air temperature in Harbin had an increasing trend from 1951 to 2008, especially after 1978. The increase of the annual minimum temperature was greater than that of the annual maximum temperature and annual mean temperature. Annual precipitation slightly increased, but not significantly. In the period of 1963-2008, bud burst, beginning of leaf expansion and first flowering of the 4 species all shifted to 5.7 d, 10.2 d and 7.9 d earlier, respectively, and end of leaf-falling was delayed for 7.5 d. The pattern of phenological change was consistent with that of air temperature change. The phenophases earlier or later was mainly subjected to air temperature, especially the mean temperature of the same month and previous month when phenophase began. The phenophase had little correlation with the precipitation. When the mean temperature in March rose up by 1 ℃, Betula platyphylla, Juglans mandshurica, Ulmus pumila and Morus alba buds burst were advanced by 2.2 d, 2.1 d, 0.8 d and 2.3 d, respectively, beginning of their leaf expansion was advanced by 2.2 d, 2.4 d, 2.1 d and 1.7 d, respectively, and the first flowering was advanced by 2.2 d, 0.8 d, 2.2 d and 1.2 d, respectively.

Key words: broad-leaved arbor, climate change, plant phenology, Harbin