Fig. 3 Fractional annual losses of C and N (annual input of senesced needle litter/forest floor mass) in forest floors of control (closed circles, solid regression line) and fertilized stands (open circles, dashed regression line) along the gradient in soil N capital: (a) C loss and (b) N loss. In (a) the value for the fertilized plots at the site with the lowest N capital is the same as that for the control plot