Changes in Soil’s Chemical and Biochemical Properties Induced by Road Geometry in the Hyrcanian Temperate Forests

Abstract

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.

Effects of forest roads on vegetation biodiversity and soil characteristics in Hyrcanian forests

“…Cutting trees along the road reduces the incoming litter, which definitely affects the amount of organic matter in the soil. A significant increase in SOC and TN values at distances further from the road edge in the study of Rahbarisisakht et al (2021) was also observed. Soil nutrients, including available P and K, Ca and Mg, are typically reduced in roadside soils due to soil compaction.…”

“…Based on the review of studies by other researchers, the maximum effective distance of the road on the environment in various studies is often up to 100 m in the forest (Avon et al 2010, Berenji Tehrani et al 2015, Deljouei et al 2018, Picchio et al 2018, Rahbarisisakht et al 2021). A 120 m buffer was created on the side of the excavation shoulder for inventory and collection of vegetation and soil data.…”

“…Roads have made access to natural ecosystems possible for harvesting, recreation, studying and other purposes (Neher et al 2013, Picchio et al 2018, Ghanbari Motlagh et al 2020). In the science of forest management, forest roads are needed for various activities such as wildlife conservation, tourism, reforestation, forestry and harvesting, fighting against pests and diseases, and fighting fires (Delgado et al 2007, Haider et al 2018, Rahbarisisakht et al 2021, Lisboa et al 2022). Although the positive effects of forest roads are undeniable, it should not be ignored that roads cause the destruction of forest, which will have certain consequences (Deljouei et al 2018, Picchio et al 2018, Lotfalian et al 2012).…”

“…Meanwhile, reducing damage to the remaining forest stand and soil is one of the goals of forest management (Lotfalian et al 2012, Deljouei et al 2018, Zamani et al 2019). Basically, forest vegetation is sensitive to the physical characteristics of the soil (Zhou et al 2020, Rahbarisisakht et al 2021). Soil can be a factor in increasing the abundance of herbaceous cover on the side of the road and can affect the growth, composition and diversity of plant species (Neher et al 2013, Boston 2016, Fallahchai et al 2018, Picchio et al 2018).…”

Seasonal Variation of GPS Accuracy and Precision in Forest Road Mapping

“…Among other forestry infrastructure, forest roads are necessary for providing economical access to forest resources and services, representing an important component in forest management [7], [9], [30]. In order to facilitate the operations in areas managed for timber production, a well-developed network of roads is essential [2].…”