An assessment of decay among urban Tilia, Betula, and Acer trees felled as hazardous

Tree species and external signs of decay influence the felling criteria in risk assessments. Following felling in Helsinki, Finland, 133 urban trees were investigated in detail (54 trees of Tilia spp., 48 Betula spp., and 31 Acer spp.). The objective was to find out whether a local management practice could be developed to improve tree care and protection of old urban trees. There was considerable variation between the felling decisions for trees with diverse defects. In addition, a contradiction was found in the criteria for felling decisions between trees with various symptoms, especially between trees with cavities and trees with advanced stages of decay. This contradiction mostly affected Tilia spp.