Responses of mean N concentrations in green ([N]_g) and senescing leaves ([N]_s) to N addition for seven dominant species in the <i>Vitex negundo</i> (left, a and b) and <i>Spirea trilobata</i> (right, c and d) communities.

<p>Error bars indicate standard deviation (n = 6). Different letters on the error bar indicate significant differences among treatments for each species based on one-way ANOVA.