The Impact of Road Investments on the Forest Environment - Case Study: The Impact of Asphalt Roads on the Health Condition and Growth of Trees

The study was conducted within the framework of the R&D project entitled “Environmental aspects of reconstruction and construction of forest roads using selected asphalt binders”. The aim of this study was to determine the impact of an asphalt road segment located in the Przymuszewo Forest District, the Regional Directorate of the State Forests in Toruń, Poland (53°57′24.14″ N, 17°34′38.30″ E), on growth increments and health condition of trees in a 60-year-old pine stand. The first stage of the investigation required laboratory analyses and field observations to assess the impact of mineral filler and asphalt mixtures on roadside habitats. Chemical analyses were performed on samples of wood and soil collected from transects located at three distances from the asphalt road, as well as dendrological and dendrometric analyses in circular sample plots of 0.02 ha in analogous transects parallel to the selected asphalt pavement. Analyses of soils and wood showed no negative environmental impact associated with the road. Contents of all the assayed elements in wood were lower compared to their contents in soil, which indicates their markedly reduced phytoextraction. Statistical analyses showed that the asphalt road has an effect on the adjacent forest mass, but that this effect is statistically insignificant with respect to the mean annual increments diameter at breast height and the defoliation of trees growing at various distances from the road.