ARBORICULTURE ARBORICULTU & CONTENTS URBAN FORESTRY Volume 42, Issue 6, November 2016 Formerly the Journal of Arboriculture, 1975 – 2005 (Volumes 1 – 31) ® www.isa-arbor.com Andrew K. Koeser, Jess Vogt, Richard J. Hauer, Robert J. Northrop, and Ward Peterson The Cost of Not Maintaining Trees: Findings and Recommendations from an International Symposium and Summit ............................................................................................................377 Abstract. Urban trees are both an asset and a cost to municipalities. Past research has focused largely on the asset—quantify- ing and valuing the social, economic, and environmental benefits provided by trees in urban areas. Relatively fewer studies have focused on defining the appropriate level of tree care (costs or inputs) for efficiently maintaining tree health and structural integ- rity, and potential resulting liabilities. On 18–20 March 2015, the International Society of Arboriculture assembled a panel of research and industry experts for a research symposium and summit titled, The Costs of Not Maintaining Trees. In the weeks lead- ing up to the summit, the Delphi technique was initiated to help build consensus on key research questions related to the eco- nomics of trees and their care. After three iterations of questions and discussion, the panel identified 14 research topics that were deemed “very important” or “important” by at least 12 of the 14 expert panelists (80% being a commonly used threshold for con- sensus). Results of this work are intended to help focus future research and funding efforts in arboriculture and urban forestry. Key Words. Arboricultural Practices; Delphi Technique; Management Challenges; Net Benefits; Optimization; Research Summit; Stakeholder Engagement; Symposia, Urban Forest Management; Urban Tree Benefits. ® Sara R. Tanis and Deborah G. McCullough Evaluation of Xylem Discoloration in Ash Trees Associated with Macroinjections of a Systemic Insecticide..................................................................................................................389 Abstract. Emerald ash borer (EAB) (Agrilus planipennis), first identified near Detroit, Michigan, U.S., in 2002, has killed mil- lions of ash trees (Fraxinus spp.) in 28 states and two Canadian provinces to date. Trunk injections of insecticide products contain- ing emamectin benzoate (EB) (e.g., TREE-äge®) are oſten used to protect ash trees in landscapes from EAB, but wounds and poten- tial injury resulting from injections are a concern. Researchers examined 507 injection sites on 61 trees and recorded evidence of secondary wounding (e.g., external bark cracks, internal xylem necrosis and pathogen infection). Researchers assessed 233 injection sites on 22 green ash and 24 white ash trees macro-injected with a low or a medium-high rate of EB in 2008 only, or in both 2008 and 2009. Only 12 of 233 injection sites (5%) were associated with external bark cracks and there was no evidence of pathogen infection. On 39 of the 46 trees (85%), new xylem was growing over injec- tion sites. Researchers assessed 274 injection sites on 15 green ash trees injected annually with EB from 2008 to 2013 or injected in 2008 and again in 2011. Bark cracks were associated with four injection sites on three trees, but no evidence of injury was found on the other 12 trees. All 15 trees had new xylem laid over injection sites. Confocal laser scanning and polarizing digital microscopy were used to assess the integrity of discolored xylem tissue removed from the immediate area surrounding 140 injection sites on 61 trees. Researchers found no evidence of decay associated with discoloration. Key Words. Agrilus planipennis; Bark Cracks; Emamectin Benzoate; Fraxinus americana; Fraxinus pennsylvanica; Green Ash; Insecticide; Mac- roinjection; Trunk Injection; White Ash. Razieh Shojanoori and Helmi Z. M. Shafri Review on the Use of Remote Sensing for Urban Forest Monitoring ..........................................400 Abstract. Urban forests are vital in urban areas because they clean the air, absorb water, and protect the environment from intense heat. Destruction of the urban forest by increased urbanization is a considerable threat to the ecosystem. Hence, urban planners must obtain and manage information about urban forests, but the complexity of urban areas has made these tasks difficult. With developments in remote-sensing technologies, the moni- toring and detection of urban forests can be achieved without performing any field measurements. In this study, different remote-sensing imageries and various methods are evaluated to obtain urban forest information. This review demonstrates that very high resolution (VHR) satellite imagery, such as from WorldView-2, is the most efficient data that can be used to obtain urban forest information. The use of the combination of LiDAR data with VHR imagery increases the accuracy of information, particularly about tree crown delineation. Traditional pixel-based classification methods are not effectively applicable to obtain urban tree information because of significant spectral variability in urban areas. An object-based classification technique, which uses spatial, textural, and color information, can be a potential method to detect urban forest and tree species discrimination. The new VHR imaging method, which uses the object-based technique, is recommended to overcome limitations of collecting urban forest information. Key Words. LiDAR; Object-Based Classification; Pixel-Based Classification; Satellite Imagery; Tree Crown Delineation; Tree Species Detection. ©2016 | International Society of Arboriculture | ISSN:1935-5297
November 2016
| Title Name |
Pages |
Delete |
Url |
| Empty |
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success. You will be contacted by Washington Gas with follow-up information regarding your request.
This process might take longer please wait
