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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.

Forest management aims to preserve integrity and ecosystem resilience. Conservation and species invasion patterns must be determined in managed landscapes. The objectives of this study were to identify proxies that allowed plant species invasion (natives and exotics) and define thresholds of human impacts to improve management. We also wanted to identify indicator species for different impacts and environments. A total of 165 plots were measured in Nothofagus antarctica forests and associated open lands (dry and wet grasslands) in Tierra del Fuego (Argentina). We found differences in the studied variables across the landscape and among different uses and impacts. Human impacts influence land types, emphasizing the importance of managing intensities. Indicator plant species allowed for the identification of potential ecological thresholds related to human impacts and the establishment of species linked to ecological and economic degradation, e.g., Bolax gummifera and Azorella trifurcata (cushion plants) were associated with high grazing pressure in grasslands and fires in forested areas, while Rumex acetosella and Achillea millefolium (erect herbs), typically associated with forested areas, were related to high harvesting pressures and fire impacts. These findings contribute to our understanding of the long-term effects of some human impacts (e.g., harvesting and ranching) and allow us to define variables of monitoring and indicator species for each impact type.