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Rating of parameters used to assess tree vitality by urban foresters and ecologists in Sweden, using the Delphi method

Östberg, Johan and Sandberg, Karin and Wiström, Björn (2021). Rating of parameters used to assess tree vitality by urban foresters and ecologists in Sweden, using the Delphi method. Urban Forestry & Urban Greening. 62 , 127134
[Research article]

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Management of urban trees is key to sustaining and increasing essential ecosystem services, and most management decisions are made based on urban tree inventories. Vitality is one of the key parameters when conducting tree inventories. However, consensus on how vitality should be assessed is lacking, and there is limited understanding of how visual vitality assessments are affected by aspects of different professional background, growing sites and tree age. In a Delphi study with 19 participants completing the whole study, we asked urban foresters and ecologists to assess the vitality of 21 trees in urban and rural settings and to rate how important 40 different parameters were for their assessment of each tree’s vitality. The data obtained were analysed using Cronbach’s alpha, unconstrained ordination, hierarchal clustering and indicator values. In testing for differences, mixed general linear models and constrained ordination were used. Professionals participating in the study showed good overall agreement in ranking trees as more or less vital, but with large differences in what was considered a fully vital tree. When performing vitality assessments, the parameters used differed between old and young trees, and between urban and rural sites. There was also a systematic difference between urban foresters and ecologists in performing tree vitality assessments, with ecologists consistently rating tree vitality higher and using fewer parameters. Parameters used for assessing vitality comprised aspects relating to sign of decay, external damage, loss/death of biomass, growth performance and site conditions. Vitality should thus be regarded as a complex parameter that needs calibration-based assessment approaches and the person performing the assessment should always be included as an additional variable. Overall, this study clearly showed the need to establish consensus on how tree vitality should be assessed and rated.

Authors/Creators:Östberg, Johan and Sandberg, Karin and Wiström, Björn
Title:Rating of parameters used to assess tree vitality by urban foresters and ecologists in Sweden, using the Delphi method
Series Name/Journal:Urban Forestry & Urban Greening
Year of publishing :2021
Article number:127134
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Published version
Copyright:Creative Commons: Attribution 4.0
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Ecology
Keywords:tree management, urban tree inventory, urban forestry
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Type of IDID
ID Code:24540
Faculty:LTV - Fakulteten för landskapsarkitektur, trädgårds- och växtproduktionsvetenskap
Department:(LTJ, LTV) > Department of Landscape Architecture, Planning and Management
Deposited By: SLUpub Connector
Deposited On:14 Jun 2021 14:43
Metadata Last Modified:16 May 2022 20:33

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