Fig. 1. (a) Lead content, (b) concentration of Pb per unit organic matter, and (c) organic matter content of the forest floor as a function of stand age in three stands at the HBEF, six stands at the BEF, and seven stands elsewhere in the WMNF. At HBEF, W6 was sampled seven times, W1 was sampled three times, and W5 was sampled once. Lead content of W6 = 1.78 g m^–2 to 0.0118 g m^–2 yr^–1 x age (yr).