Fig. 3From: Nitrogen addition to the canopy of Castanopsis chinensis (Sprengel) Hance promoted xylem formation in a subtropical forest in ChinaEffects of canopy N addition on averaged growth rate of C. chinensis during the early and late growth season in CK and CN in 2015 (left panel) and 2016 (right panel). The black bar and the gray bar represent averaged growth rate. CK and CN represent control and N-treated trees. *** indicates significance at P < 0.001Back to article page