Characteristics of Spring Phenological Changes in China over the Past 50 Years

Table 1

Species selected and corresponding observation sites in the study. Site numbers correspond to site numbers shown in Figure 1.

Species	Numbers of sites	Distribution sites (site number)
Fraxinus chinensis	3	9, 15, 28
Ailanthus altissima	7	8, 9, 12, 14, 15, 17, 21
Melia azedarach	16	14, 15, 17, 18, 23, 24, 24, 25, 26, 29, 30, 31, 33
Paulownia tomentosa	15	9, 10, 13, 15, 18, 19, 20, 21, 24, 25, 26, 28, 29, 30, 32
Ulmus pumila	18	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 28