Soil surface is directly affected by heavy traffic of machinery during harvesting operations. Machine traffic often causes damage to forest soil which is visible on the surface (ruts) and invisible changes in, for example, bulk density, penetration resistance, etc. Close-range photogrammetry is the state-of-the-art method used for recording and evaluation of visible changes. This study aims to analyze soil surface changes caused by traffic of three types of wheeled skidders without a load on Cambisol soil in Central Slovakia. We use the Structure-from-Motion (SfM) close-range photogrammetry to record and evaluate depths of ruts and their volumes after 40 passes of individual skidders. We compared Root Mean Square Errors (RMSEs) of dense point clouds created from various numbers of images taken for individual plots. Rut volume changes calculated by the SfM method and from the manual measurements were compared for one skidder. The final values of RMSE did not exceed 10 mm except for the plot with the lowest number of photos. The final rut depths varied between 0.026 and 0.050 m, and their final volume fluctuated from 0.021 to 0.089 m³. The skidder type and the terrain slope had significant impacts on magnitudes of soil changes. The results of the manual and SfM methods assessing soil changes were correlated. Based on the presented results we can conclude that the SfM method can be applied to detect soil surface changes after traffic of forestry machinery.

Deadwood is an important component of forests that fulfils many ecosystem functions. The occurrence, amount and spatial distribution of deadwood in forest ecosystems depend on tree species composition, historical development and past management. In this presented study, we assessed the total amount of deadwood, including fine and coarse woody debris at five areas of predominantly broadleaved forests within the University Forest Enterprise of the Technical University in Zvolen, Slovakia that had been disturbed by windstorm Žofia in 2014. Windthrown wood was salvaged between May 2014 and October 2015. In the year 2018, we performed an inventory of deadwood that remained on-site after salvage logging. The mean volume of deadwood recorded at sample plots fluctuated between 35.96 m³/ha and 176.06 m³/ha and mean deadwood coverage values at individual disturbed areas ranged from 7.27 to 17.91%. In the work, we derived several models for the estimation of deadwood volume based on deadwood coverage and/or diameter, which showed that these characteristics are good proxies of deadwood volume. The tests, involving close-range photogrammetry methods for deadwood quantification, revealed that the number of pieces and the coverage of deadwood recorded in photos was significantly lower than the values derived from field measurements.

Forest roads are necessary to provide access to forests and are also used by users other than forest owners and the timber industry. Their usage for recreation and hiking has been increasing in the last years. From 1/2020 to 12/2020, we performed research on traffic loads and the use of forest roads at an area of the University Forest Enterprise of Technical University in Zvolen. For this purpose, we selected two localities, namely Včelien = A locality and Štagiar = B locality. We monitored transport intensity at selected localities with images obtained from two identical Trail Spromise S308 cameras. We examined the impact of lockdown periods during the COVID-19 pandemics on forest recreation in the year 2020 with the Kruskal–Wallis ANOVA. Multiple comparisons of p values showed there were no differences in the recreational usage of forest roads between the lockdown periods and periods without restrictions. We found that recreation activities peaked in summer and spring. Recreation and transport at selected localities did not have a negative impact on animal occurrence, as the regression and correlation analysis revealed only a low negative relationship with r = 0.029. When considering the number of passages, roads were used for recreation and other non-forestry purposes at approximately 36%. From the perspective of the weight load, recreation accounted for about 10%.

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic