Non-traditional alley tree species for urban conditions

Changing environmental conditions and various sources of stress have negative impacts on the growth, survival, and functionality of urban trees. Growing attention is being paid to the selection of tree species that are resilient and adaptable to urban conditions. The presented research investigates Pyrus pyraster (L.) Burgsd. and Sorbus domestica L. These taxa are not classified as traditional alley tree species. However, in the extreme environments of urban settlements with a high risk of soil drought, their plasticity and adaptive potential can be exploited. Long-lived and wind-pollinated tree species are generally presumed to have broad phenotypic plasticity. According to the results of our previous research, these species are tolerant to drought and high temperatures that are considered to be significant stressors for woody plants in urban settlements. The aims of this study were to present the growth forms of the studied species, as well as the possibilities for on-site maintenance of urban trees. In 2017, young plants of generative origin (96 from each taxon) were planted in the experimental area. In 2019, the height, form, and overall survival of these young trees were evaluated. Different tree forms were presented for both species, and different approaches for maintenance and regulation of their growth were investigated. In the coming years, research on tree growth models and the influence of pruning applied to correct young tree defects will be carried out. We expect that wider utilization of these species and their active management will support biodiversity in urban ecosystems.