| Abstract: | To understand how coexisting temperate tree species react to nitrogen (N) addition, seedlings of two coexisting species, Phellodendron amurense Rupr. and Fraxinus mandshurica Rupr. were transplanted to a controlled environment. Seedlings were then planted in two competition scenarios, control and mixed, and then subjected to four N addition treatments. The seedling growth parameters and competition effect were monitored and analyzed. The height and stem-base diameter showed a positive response to the N addition in all competition scenarios except for mixed P. amurense, which responded negatively. Chlorophyll content of the seedlings showed a positive relationship to N addition while the chlorophyll a/b showed a complex trend. The addition of N showed a positive relationship to the competition effect of diameter growth in both species and height growth in P. amurense. These results indicate that F. mandshurica may be more sensitive to N addition and could benefit more from N addition than P. amurense. With an increasing N input from the atmosphere, forests may be more suitable for F. mandshurica reducing the abundance of P. amurense. |
