Grading of Parameters for Urban Tree Inventories by City Officials, Arborists, and Academics Using the Delphi Method

Abstract

Tree inventories are expensive to conduct and update, so every inventory carried out must be maximized. However, increasing the number of constituent parameters increases the cost of performing and updating the inventory, illustrating the need for careful parameter selection. This paper reports the results of a systematic expert rating of tree inventories aiming to quantify the relative importance of each parameter. Using the Delphi method, panels comprising city officials, arborists and academics rated a total of 148 parameters. In order of total mean score, the top ranking parameters, which can serve as a guide for decision-making at practical level and for standardization of tree inventories, were: Scientific name of the tree species and genera, Vitality, Coordinates, Hazard class and Identification number.The study also examined whether the different responsibilities and usage of urban tree databases among organizations and people engaged in urban tree inventories affected their prioritization. The results revealed noticeable dissimilarities in the ranking of parameters between the panels, underlining the need for collaboration between the research community and those commissioning, administrating and conducting inventories. Only by applying such a transdisciplinary approach to parameter selection can urban tree inventories be strengthened and made more relevant.

Urban Forest Indicators for Planning and Designing Future Forests

“…The method provides structured feedback to participants after each round in order to facilitate an anonymous dialogue about the subject matter. It has been used once before to solicit expert feedback on parameters for urban forest inventories [24].…”

“…Indicators were developed from relevant literature that represented a wide range of economic, environmental and social issues [21][22][23][24][25][26]. The indicators included both quantitative and qualitative issues (see Appendix Table A1).…”

“…Criteria and indicators are a commonly used tool in the profession of forestry [17][18][19] and urban design [20]. There have been a few studies looking at indicator sets for urban forestry [21][22][23][24][25][26]. None of the existing indicator sets captured the full range of urban forest benefits required for this study.…”

“…There have been a few recent attempts to create indicator sets for urban forest resources [22][23][24]. Current indicator sets proposed for urban forestry have shortcomings.…”

“…If municipalities aren't using the indicators, this could show they aren't measuring the issues urban foresters are most interested in. While most cities have a set of management parameters, a study by Östberg et al [24] found few parameters that were used by multiple cities. This lack of standardization between cities makes comparison of performance between cities difficult.…”