Forestry machine traffic causes a number of changes that are not immediately reflected in morphological changes of surface soil. These changes are physical and chemical in nature. The change in subsurface soil CO₂ concentration was one of the parameters of interest. The critical CO₂ concentration is thought to fluctuate around 0.6%. The primary objective of this paper was to determine the impact of forestry machine traffic on subsurface soil CO₂ concentration. We measured CO₂ concentration in the areas undisturbed by machinery and in the ruts in skid trails in eight forest stands. The measurements were performed using a Vaisala MI 70 meter. The results confirmed significant differences in gas concentrations between the individual measurement sites. In the ruts of the skid trails, CO₂ concentrations fluctuated in a range of 0.5 to 2.81% and significantly exceeded the critical concentration. Moisture content and bulk density had a significant impact on the change in gas concentration beneath the surface, which was confirmed by multivariate analysis of variance that revealed that the values of the coefficient of correlation fluctuated in a range of 0.39 to 0.74.

This paper was focused on determining whether gravimetric sampling and impedance method of measuring soil moisture content provided different results and if they did, what was the size of the differences between particular methods on rendzinas and cambisols. The means of moisture content should be equal when using both methods on similar spots. During the research, an Eijkelkamp Penetrologger penetrometer equipped with impedance probes and gravimetric sampling cylinders from Eijkelkamp were used. The samples were taken from the undisturbed stand, ruts, and the centre of the skid trail. The impedance probes were inserted six centimetres deep into the soil. Soil samples were taken from similar depth in order to calculate the moisture content through the gravimetric method. 138 measurements were carried out for each method. The minimal difference of moisture contents measured by individual methods was 0.01%, maximal difference was 22.06%, and on average it was 7.42%. Oneway ANOVA was used for first stage analysis of the statistical sample. It proved that the differences between measurements were statistically significant in two out of three considered stands. Tukey’s HSD test was used to identify which data groups contributed to refuting the aforementioned hypothesis. The test showed that in one stand all relevant pairs of data were significantly different, while in the other stand only data pairs from the ruts were significantly different. The calibration method provided by the producers did not refine the accuracy of the impedance probes sufficiently and different calibration procedures have to be used.

The paper was aimed on reforming on damage to soil caused by passage of universal wheeled tractors and forest wheeled tractors. We focused mainly on determining the changes in CO₂ content in soil after its compaction in comparison with unimpaired soil from the stand. We carried out the measurements in municipal forests of Stará Turá, in four stands, where a regeneration felling was done. We acquired data on the depth of ruts through the method of transversal profiles took samples of soil from the ruts and unimpaired stand to determine the bulk density and moisture content. We determined the content of CO₂ in stand and ruts with a Vaisala MI70 device. We selected the stands so that they would be uniform in age, terrain incline, terrain, and soil type. All of the stands had a low bearing sub – soils – flysch sandstone. This affected the rut depth after both machines passage. Rut depth indicated severe damage to the stand soil. We also observed severe differences in CO₂ content of the compacted soil. Measurements in all of the stands showed a significant increase in CO₂ content after its compression. Unimpaired soil reaches volume of 0.3% and rut soil reaches 1.8%. The compressed soils contained 6x the CO₂ of uncompressed soils. The results of statistical analysis show, that moisture content affects the CO₂ content more than bulk density. Coeficients of correlation between CO₂ and moisture content were r = 0.68 and 0.52 and between CO₂ and balk density were r = 0.26 and 0.36. Increase in moisture content causes CO₂ accumulation. Combined effects of these two characteristics are significant and show very strong correlation. There was for example r = 0.83 and independent characteristics influenced dependent on 69%. From the outcomes the measurements we can state, that the passage of mechanisms causes significant changes in the stand soil.