Populus × euramericana is a species characterized by fast growth and simple vegetative propagation and is often planted in the parks of Novi Sad. During 2017, dieback of P. x euroamericana was observed in the Železnički Park in Novi Sad. The dieback continued in the following years, the leaning of the trees was noticed as well as mushrooms of the poplar rot fungus Cyclocybe aegerita growing in clusters at tree bases. Thus in October 2022, the static stability and internal structure of P. × euramericana wood was checked using semi-destructive micro-drilling method and IML PD 400 resistograph and the different stages of the structural erosion of the wood were observed. Ophiostomatoid fungi, fusarioid fungi and C. aegerita were isolated from symptomatic wood samples. Molecular phylogenetic analyzes confirmed that the fruiting bodies at tree bases belong to the species C. aegerita. Frequent climate extremes along with other stressful factors in urban areas make poplar trees sensitive to windstorms, windbreaks, and attack of opportunistic pathogens. Therefore, it is essential to conduct intensive monitoring of health and stability of poplar trees in urban areas and this should be done using resistance measurement devices for the detection of wood decay like resistograph. This instrument provides insight into the tree structure and the possibility of timely reaction to make city parks a safe and pleasant place for people to rest and relax.