Acta Scientiarum Polonorum
Silvarum Colendarum Ratio et Industria Lignaria

Introduction. The paper presents an assessment of threat associated with the roadside trees growing in the gauge of provincial road no. 387, in the section running through the Table Mountains National Park (TMNP).

Material and methods. The study was conducted on a section of the road with a total length of 17.7 km, from Radków (chainage 14+800) to Kudowa-Zdrój (chainage 32+500). In a field inventory the roadside trees were assessed in terms of such symptoms of poor tree health condition as the presence of dying and dead branches in the tree crown, which could result in their breaking off, rotten fragments in the trunk structure and symptoms of root system decomposition. A five-point assessment scale was used to diagnose the degree of threat posed by inventoried roadside trees. Official documentation related to the assessment of the condition of roadside trees and the threat they posed in previous years (from 2018 to 2022) was also analyzed. For this task, the applications for permits for tree felling provided by the road manager – the Lower Silesian Road and Rail Service in Wrocław were used.

Results. The number of problematic trees inventoried in 2022 in the examined section of road no. 387 amounted to 91, which constituted approx. 12% of all trees (750) growing in the right-of-way, including mainly Norway maple, sycamore maple and common ash. Nearly half of those showing symptoms that could generate problems for road users received ratings of 3, 4 or 5, indicating the most significant threat which qualified them for removal (a total of 47, including 29 dead trees). The documentation of the Lower Silesian Road and Rail Service in Wrocław showed that among the hazardous trees proposed for removal in the period 2018–2022 in the total number of 170 trees two species dominated: Norway maple (55%) and common ash (42%). 

Conclusions. The leading causes of the threat were branches and boughs located directly above the road crown and dead trees. In most cases, tree death was related to mechanical damage to the trunks caused by cars, which results directly from periodically intensive car and tourist traffic. Dead and dying trees should be cut down. New plantings in the right-of-way may be considered together with the design of engineering elements for their protection (e.g. appropriate protective barriers) or the implementation of an individual project reconciling the plantings with the option of parking cars. The possibility of moving newly planted trees away from the edge of the roadway, preferably behind the outer slope of the roadside ditch, should be considered. Protecting the area within the road zone in the TMNP is facilitated by expanding public transport for tourist purposes and limiting car traffic.