Rapid urbanization, unregulated industrialization, growing transport intensity and agricultural activities have created a problem of heavy metal (HM) contamination worldwide. HMs are long-term contaminants with the ability to accumulate in soil and plants and have no natural way to be removed. Forests near local contamination sources have been subjected to HMs concentration measurements. Trees are HMs bioindicators capable to record HM concentrations in the environment in the past. In this paper, concentrations of HMs determined in wood trees were compared with phytotoxic, excessive, deficiency and naturally found HM concentrations in plants. Results of our investigation showed that HM concentrations in trees that grew in potentially contaminated areas did not exceed phytotoxic and excessive values of HMs found in plants. Concentrations of HMs in a wood of pines varied: Ni – 0.1–3.50 mg·kg^–1; Cr – 0.1–1.50 mg·kg^–1; Cu – 0.25–3.00 mg·kg^–1; Mn – 10–160 mg·kg^–1; Zn – 2–75 mg·kg^–1, Pb – 0.05–2.80 mg·kg^–1 and those for birch ranged: Ni – 0.90–3.20 mg·kg^–1; Cr – 0.90–2.50 mg·kg^–1; Mn – 40–130 mg·kg^–1; Pb – 1.0–3.50 mg·kg^–1. The higher transfer of HMs to wood was associated with higher concentrations of HMs in tree environment (soil and nearby water bodies) and the function of some HMs as elements necessary for tree physiological processes. The values of HM transfer factors for trees were: Ni – 0.001–0.55; Cu – 0.04–0.45; Zn – 0.03–0.6; Mn – 0.001–0.75; Pb – 0.002–0.085; Cr – 0.005–0.11.

Keywords: annual rings, birch, heavy metals, military grounds, pine