Recent research has indicated an increase in the likelihood and impact of tree failure. The potential for trees to fail relates to various biomechanical and physical factors. Strikingly, there seems to be an absence of tree risk assessment methods supported by observations, despite an increasing availability of variables and parameters measured by scientists, arborists and practitioners. Current urban tree risk assessments vary due to differences in experience, training, and personal opinions of assessors. This stresses the need for a more objective method to assess the hazardousness of urban trees. The aim of this study is to provide an overview of factors that influence tree failure including stem failure, root failure and branch failure. A systematic literature review according to the PRISMA guidelines has been performed in databases, supported by backward referencing: 161 articles were reviewed revealing 142 different factors which influenced tree failure. A meta-analysis of effect sizes and p-values was executed on those factors which were associated directly with any type of tree failure. Bayes Factor was calculated to assess the likelihood that the selected factors appear in case of tree failure. Publication bias was analysed visually by funnel plots and results by regression tests. The results provide evidence that the factors Height and Stem weight positively relate to stem failure, followed by Age, DBH, DBH squared times H, and Cubed DBH (DBH3) and Tree weight. Stem weight and Tree weight were found to relate positively to root failure. For branch failure no relating factors were found. We recommend that arborists collect further data on these factors. From this review it can further be concluded that there is no commonly shared understanding, model or function available that considers all factors which can explain the different types of tree failure. This complicates risk estimations that include the failure potential of urban trees.
MULTIFILE
The environment of the(Dutch) building industry is increasingly turbulent. There are many cges for the building industry. Innovative tendering, better marketing, openness and transparency are examples of this. A strong reduction in failure costs (estimated at between 10 and 25% of the total costs) and an increase in quality are also necessary. Lastly, the declining inflow of young people has to be mentioned. The image of the building industry is not particularly good and students prefer to choose other industries. The building industry therefore has to change and, so far, everyone agrees. Evidently both the building industry and its environment are very keen to change; the sincere will is there, and money and energy are available, but it seems that efforts are not proceeding in a very planned or coordinated manner at present. And this is causing fragmentation and, therefore, sub optimisation. How does sectoral change proceed and how is this process to be managed? That is the central question in this paper.
DOCUMENT
Our current smart society, where problems and frictions are smoothed out with smart, often invisible technology like AI and smart sensors, calls for designers who unravel and open the smart fabric. Societies are not malleable, and moreover, a smooth society without rough edges is neither desirable nor livable. In this paper we argue for designing friction to enhance a more nuanced debate of smart cities in which conflicting values are better expressed. Based on our experiences with the Moral Design Game, an adversarial design activity, we came to understand the value of creating tangible vessels to highlight conflict and dipartite feelings surrounding smart cities.
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