Although skid roads are more and more commonly used in Poland, they are still quite often criticised due to a certain loss of wood volume and the impact on edge trees. In this context, the results of the research described in this article can be used as a substantive contribution to discussions about strip roads. Research was carried out in a 42-year-old pine tree stand (Pinus sylvestris L.) in the Notecka Forest, where thinning had been performed and 2.5 and 3.5 m wide strip roads had been cut 10 years before. The analysis comprised two five-year periods recording diameter growth and pith eccentricity in trees growing at the distance zones of 0–1 m (adjacent trees), 2–4 m and 8–10 m (the control) away from the strip roads. The differences in growth and eccentricity between the different distance zones as well as the frequency of pith eccentricity in the N-W, S-W, N-E and S-E directions were assessed, related to the distance from the strip road and the measurement height. The measurements of the analysed traits were conducted on wood discs cut from the centres of two-metre-long sections on sample trees (12 trees in each distance zone). The trees growing directly beside the strip roads were statistically significantly thicker than those growing 8–10 m away, and in the case of the trees beside the narrower strip roads, in the second 5-year period, they were also thicker than the trees from the 2–4 m distance zone. The effect of the wider strip roads in the first growth period was also significant for the trees growing 3 m away from the strip road (their growth in this period was significantly greater than that of trees in the control zone). The research into tree-pith eccentricity showed no differences due to relative distance from the strip road. Furthermore, no statistically significant relationship between the distance of trees from the strip road, measurement height and frequency of tree-pith eccentricity to the N-W and S-W were found.

Crowns of trees neighboring a strip road are exposed to greater amounts of sunlight, which may result in the so-called edge effect, leading to enhanced tree growth. The aim of this study was to assess the edge effect after twenty years since the clearing of strip roads in terms of diameters at breast height (DBH) and tree height, as well as crown base height and crown length. Based on the results of earlier measurements temporal changes in tree diameters at strip roads were also evaluated. Analyses were conducted in a pine stand, where strip roads of 3.5 m wide strip roads) and 2.5 m narrow strip roads) were cleared at the stand age of 31 years. After eight years the width of the narrow strip roads was increased to 3.5 m. Measurements were taken on trees growing directly at strip roads (edge trees) and those approx. 4.5 m from the road axis, as well as in middle of the distance between neighboring strip roads (as a reference). Trees growing at strip roads edge had statistically significantly larger diameters at breast height than trees growing farther from strip roads. These differences in tree height were slight and statistically non-significant, whereas crowns of trees growing at the strip road edges had lower bases and were longer compared to crowns of other trees. Analysis of DBH data recorded during 20-year measurements showed a gradual reduction in the effect of strip roads on diameters of trees growing at strip road edges.