[Spatial Distribution Features of the Root Biomass of Some Tree Species (Picea abies, Pinus sylvestris, Betula sp.)].

The effect of intra- and interspecific competition on the spatial distribution of the biomass and mortmass of woody plant roots in mixed tree stands has been studied. It has been found that the mass of roots in the samples from tree pairs of different species is higher than in the samples from monospecific pairs. Species-specific differences in the vertical distribution of roots and the effect of intra- and interspecific competition on the spatial structure of biomass have been shown. It has been noted that the proportion of dead roots increases almost linearly with depth.

[Global climate change and carbon balance in forest ecosystems of boreal zones: imitating modeling as a forecast tool].

The individually oriented system of the EFIMOD models simulating carbon and nitrogen flows in forest ecosystems has been used for forecasting the response of forest ecosystems to various forest exploitation regimes with climate change. As input data the forest management materials for the Manturovskii forestry of the Kostroma region were used. It has been shown that increase of mid-annual temperatures and rainfall influence the redistribution of carbon and nitrogen supply in organic form: supply increase of these elements in phytomass simultaneously with depletion of them in soil occurred. The most carbon and nitrogen accumulation in forest ecosystems occurs in the scenario without felling. In addition, in this scenario only the ecosystems of the modeling territory function as a carbon drain; in the other two scenarios (with selective and total felling) they function as a source of carbon. Climate changes greatly influence the decomposition rate of organic matter in soil, which leads to increased emission of carbonic acid. The second consequence of the increase in the destruction rate is nitrogen increase in the soil in a form available for plants that entails production increase of plantations.

Real Atmosphere Laboratory Measurements of the 118-GHz Oxygen Line: Shape, Shift, and Broadening of the Line.

For the first time the 118-GHz line of the oxygen molecule was investigated in the laboratory under a real atmosphere. The experiment was carried out by modern resonator spectroscopy methods on the laboratory air at atmospheric pressure. The shape of the line under the real atmosphere was found to fit the Van Vleck-Weisskopf profile within experimental accuracy. The air broadening parameter value was defined as 2.14+/-0.07 MHz/Torr. The observed atmosphere oxygen line central frequency was found to be shifted down at about 150 MHz from the line center measured at low pressures, which gives a value of -0.19+/-0.08 MHz/Torr for the air shift parameter. A comparison with previous investigations is presented and reprocessing of some experimental results of other authors was carried out. Results of reprocessing agree with the findings of the present paper. Copyright 2001 Academic Press.