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Regional data on Pb concentrations in wood biomass have been obtained on the
base of special wood sampling in background area. As can see from Table 2, Pb
concentrations in stem wood are lower for all tree types in comparison with the
values obtained for branches and bark. The differences equal 4-6 times. As can be
mentioned in (Remezov et al., 1959), concentrations of the element in different tree
parts are maintained during all vegetation period if environmental conditions are
not changed. So, the same data can be used for estimations of metal removing with
biomass for trees of either age.
Table 2. Data on Pb accumulation in wood biomass of the main tree types in the
central Russia (based on: Zolotareva et al., 1983; Priputina et al., 2003)
Tree Type Compartments Samples number Pb, mg/kg
stem 16 0.51
Spruce
branches 14 3.00
bark 6 2.00
stem 11 0.38
Pine
branches 10 1.75
bark 7 1.70
stem 10 0.43
Oak
branches 10 2.70
bark 4 5.00
stem 10 0.68
Birch
branches 15 2.54
bark 10 1.45
As known, there are differences in the rates of annual biomass growth for the
trees of different ages (as well as tree compartments) that can be taken into
consideration in regional estimations (Fig.1). The results of wood productivity
simulations (based on EFIMOD) show that average rates of annual biomass growth
at age of 50-80(100) years are higher in 1.5-2 times in comparison with average
data calculated for 10-100(150) years period. Taking into account the differences
of Pb concentrations in the wood of stem/braches the fluxes of metal removal with
biomass uptake have been calculated for pure stands of the main tree types: Spruce,
Pine, Oak, Birch (Tab.3).
Data presented in this paper had been used for preliminary calculating and
mapping of critical loads of Pb for forest ecosystems in the basin of the Upper Oka.
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