Table of Contents Brian Kane and H. Dennis Ryan Residual Strength of Carabiners Used by Tree Climbers ................................................................ 75 Abstract. Tree climbers increasingly use carabiners and apply them in situations for which they are not designed. Because failure of carabiners can result in serious injury or death, the following study tested how well carabiners endure the stress to which climbers subject them. This study distributed carabiners of four types (all manufactured by Petzl) to climbers in Massachusetts and New York, USA, and collected them a year later. Then, carabiners were broken in a universal testing machine and measured the maximum load, Key Words. Carabiner; Strength; Tree Climbing. Giovanni Sanesi, Emilio Padoa-Schioppa, Leonardo Lorusso Luciana Bottoni, and Raffaele Lafortezza Avian Ecological Diversity as an Indicator of Urban Forest Functionality. Results from Two Case Studies in Northern and Southern Italy ................................................................................. 80 Abstract. Greenspaces and forest greenspaces having different trees contribute to a number of environmental structural attributes (e.g., vegetation type, functions in urban environments, such as the survival of urban-dwelling species (e.g., bird species). This paper analyzes the relationship between greenspace characteristics (structural and spatial attributes) and the diversity of avian ecology species. This provides research findings coming from two studies conducted in Italy. Using point-count method, a quantification was done of the abundance and diversity of bird species in a number of tree height) specimens and species observed in and spatial characteristics the two studies. A positive correlation appeared also between distance to the city centre and richness and abundance of bird species. Finally, we discuss some of the main implications for enhancing the functional attributes of greenspaces by using avian ecological indicators to inform ecologically sound urban planning and design. Key Words. Urban Environments; Point-Counts; Urban Biodiversity; Forest Birds; Italy; Ecological Indicators; Urban Greenspaces. Cristina Nali and Giacomo Lorenzini Residents’ Perception of Tree Diseases in the Urban Environment ................................................ 87 Abstract. Urban greenspaces are essential for the health and well-being of citizens and the presence of trees is a key element for the improvement of urban environments. But trees may become a factor of risk for the citizen when they are diseased, declin- ing or dead. Common people are usually unaware of the intimate causes of plant diseases. Based on a balanced sample of 944 detailed interviews carried out in a structured format by university students, a survey was performed to monitor the perception of citizens of evergreen ornamental plants (Quercus ilex) killed by a root disease. Most of the interviewed were customary or moder- ate frequenters of the venue. Most of the respondents were able to recognize the differences between the dead tree and other con- specific normal individuals, and 86.2% were aware of the risks connected with the collapse of unhealthy trees. Differences amongst genders, age groups, educational levels, and occupation were observed concerning the supposed cause of the death (due to a fungal rot disease). Environmental pollution was indicated as the culprit mainly by young people. Surprisingly, 42.9% of respondents were unable (or unavailable) to give suggestions to administrators concerning the management of public greenery. Key Words. Environmental Psychology; Declining Trees; Group Interviews; Greenspaces. Christopher J. Luley, David J. Nowak, and Eric J. Greenfield Frequency and Severity of Trunk Decay in Street Tree Maples in Four New York Cities ................. 94 Abstract. A proportional random selection of street tree Norway, silver, and sugar maples, and other species among four diameter classes were surveyed in the U.S.’ New York cities of Albany, Buffalo, Rochester, and Syracuse for decay incidence and severity. Decay was determined by drilling sampled trees with a Resistograph and calculating the ratio of sound wood to radius. Overall, 58.3% of the sampled trees had some amount of decay and incidence was highest in sugar maples and in the largest size class trees. However, decay incidence was high (53.2%) even in the smallest diameter tree size class (30.5–45.7cm (12–18 in). Decay severity was greatest in silver maple and in the largest diameter trees, although only 3.2% of shows that decay is common in street trees but is seldom severe. It also suggests the trees sampled had serious decay. The study that decay becomes established early in the life of street trees but is most severe in larger diameter trees and in trees that compartmentalize decay poorly such as silver maple. The frequency and severity of decay in the cities studied indicates that they need to continue to identify and manage trees with decay. Key Words. Decay; Resistograph; Street trees; Maples; Hazard trees; Carbon loss (e.g., location, connectivity). Results showed positive correlations between greenspaces with a more diverse and mature forest vegetation and the number of as well as surface roughness. No carabiners broke below their rated strength; and used carabiners were, with one exception, as strong as new carabiners. Surface roughness was a weak, but significant, predictor of strength. Findings are discussed in light of climber safety and the importance of conducting long-term studies. ©2009 | International Society of Arboriculture | ISSN:1935-5297
March 2009
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