<p><em>Aim of study: </em>The primary objective of this paper was to compare the effects of different types of forestry machine chassis on the compaction of the top layers of soil and to define the soil moisture content level, at which machine traffic results in maximum compaction.</p><p><em>Area of study:</em> Measurements were conducted in eight forest stands located in Slovakia and the Czech Republic. The soil types in the stands subjected to the study were luvisols, stagnosols, cambisols, and rendzinas.</p><p><em>Material and Methods:</em> The measurements were focused on tracked and wheeled (equipped with low pressure tyres) cut-to-length machines, and skidders equipped with wide and standard tyres. The bulk density of soil was determined from soil samples extracted from the ruts, the centre of the skid trail, and the undisturbed stand. To determine soil moisture content, at which the soil is the most susceptible to compaction, the Proctor standard test was employed.</p><p><em>Main results:</em> The moisture content for maximal compaction fluctuated from 12% to 34.06%. Wheeled machines compacted the soil to 1.24 – 1.36 g.cm^-3 (30.3 – 35.4 % compaction) in dried state. Bulk density of soil in stands where tracked machine operated was lower, ranging from 1.02 to 1.06 g.cm^-3 (25.3 % compaction).</p><p><em>Research highlights:</em> All wheeled machines caused the same amount of soil compaction in the ruts, despite differences in tyres, machine weight, etc. Maximum compaction caused by forestry machines occurred at minimal moisture contents, easily achievable in European climatic conditions.  </p><p><strong>Keywords:</strong> soil compaction; bulk density; soil moisture content limits; cut-to-length machines; skidders.</p>

No abstract

No abstract

No abstract

Forest harvesting causes a lot of damage, which results in damage of the remaining stand. These damages have different character. Their origin, range, and type is affected by the type of machinery, harvesting technology and the machine operator. This paper was focused on the negative impact of three types of forest harvesting technologies to the remaining stand. We considered wheeled skidder technology, and CTL technology with wheeled and tracked chassis. The harvest in stands varied between 21 and 52%, with an average concentration of felling 13.7–95.4 m3 per one skid trail. We observed that the damage rate in stands processed by CTL technology was between 7.3 and 8.03%. Skidder technologies caused damage between 17.8% and 44.6%. The average size of wound caused by CTL technologies was between 167 and 322 cm2. Skidder caused damages with area between 395 and 506 cm2. We also observed differences between damages caused by various types of chassis. CTL technology with tracked chassis caused more damages of timber and tree root system. We used multivariate regression and correlation analyses to evaluate the effect of stand density and intensity of harvest on the intensity of damage. The analyses did not confirm significant impact of these two characteristics on intensity of damage, with coefficients of correlation of 0.22 (stand density) and 0.53 (intensity of harvest).