Forest roads play an important role in providing access to forest resources. However, they can significantly impact the adjacent soil and vegetation. This study aimed to evaluate the effects of road geometry (RG) on the chemical and biochemical properties of adjacent soils to assist in environmentally friendly forest road planning in mountainous areas. Litter layer, canopy cover, soil organic carbon (SOC) stock, total nitrogen (TN), the activity of dehydrogenase (DHA), and urease (UA) enzymes at a 0–20 cm soil depth were measured by sampling at various distances from the road edge to 100 m into the forest interior. The measurements were done for three road geometries (RG), namely straight, curved, and bent roads, to ensure data heterogeneity and to reflect the main geometric features of the forest roads. Analysis of variance (ANOVA) showed that the effects of RG on the measured variables were statistically significant. Spearman’s correlation test clearly showed a strong positive correlation between environmental conditions, SOC, TN, DHA, and UA for given RGs. Based on piecewise linear regression analysis, the down slope direction of the straight and the inside direction of bent roads accounted for the lowest and highest ranges of ecological effects, respectively. The results of this study contribute to our understanding of the environmental effects brought about by road geometry, which can be important for forest road managers when applying the best management practices.

GPS receivers are frequently used for engineering activities in forests; however, a number of factors, including natural barriers (mountain and tree canopy) in the forested areas, affect their accuracy. The aim of this study was to evaluate the accuracy and precision of a consumer-grade GPS (Colorado 300) receiver in road mapping. For this purpose, a length of 12.2 km of main forest road was selected in the Hyrcanian forest, northern Iran, and a ground truth map was extracted from the National Cartographic Center maps. The forest road was mapped in four seasons for three days to evaluate the seasons’ effects on the location accuracy and five- and ten-meter buffers were used for the same purpose. The results of two-way ANOVA showed that there were significant differences in the precision and accuracy of the GPS receiver due to the season. The best and worst mean accuracy and precision were in spring (24.45 m and 24.97 m) and autumn (56.10 m and 53.65 m), respectively. The findings showed a positive effect of averaging (5-61% improvement in relation to season) on the position accuracy. Also, ANOVA did not show any significant differences between the overlay lengths due to season in both the five-and ten-meter buffers. It can be concluded that consumer-grade GPS receivers could meet forestry needs. The averaged accuracies in spring are acceptable for many forestry applications and satisfy the mapping requirements.