ARBORICULTURE ARBORICULTU & CONTENTS Wood Decay. Kristin S. Peterson and Thomas J. Straka Specialized Discounted Cash Flow Analysis Formulas for Valuation of Benefits and Costs of Urban Trees and Forests ........................................................................................................... 200 Abstract. Urban trees and forests have distinct benefits and costs that can be evaluated financially. While there are appraisal meth- ods commonly used to value individual trees and urban forests, one method that is difficult to use in practice is a discounted cash flow (DCF) analysis. This is the appraisal method that best accounts for the time value of money and allows for a temporal comparison of benefits and costs. Current timber appraisal methods are discussed for urban situations and DCF analysis is pre- sented as a viable supplemental appraisal method for valuation of the urban trees. Simple models are presented that allow for the solu- tion of DCF-type urban forestry valuations using conventional soſtware valuation packages. Examples are provided of typical urban tree benefit and cost scenarios, with DCF calculations of present value (PV) and net present value using the specialized DCF formulas. Key Words. Appraisal; Discount Rate; Discounted Cash Flow Analysis; Financial; Net Present Value; Present Value; Urban Forestry; Valuation. Nicholas A. Martin, Arthur H. Chappelka, Gary J. Keever, and Edward F. Loewenstein A 100% Tree Inventory Using i-Tree Eco Protocol: A Case Study at Auburn University, Alabama, U.S. ............................................................................................................................... 207 Abstract. The Auburn University campus in Auburn, Alabama, U.S., was used as the site for a case study on the applicability of i-Tree Eco using a 100% tree inventory. The 2009-2010 inventory of the managed areas of campus encompassed 238 ha. Information col- lected from each tree included diameter at breast height (DBH), tree height, crown width, percent dieback, and a tree condition rating. The complete inventory included 7,345 trees with Lagerstroemia spp. (crapemyrtle), Quercus phellos (willow oak), and Pinus taeda (lob- lolly pine) being the most numerous species on campus. Average DBH and total height of all trees were 16.4 cm and 8.5 m, respec- tively, with an estimated canopy cover of approximately 16%. Two tree condition ratings were recorded for each tree and results indicated that percent dieback alone is not a sufficient measure to evaluate tree condition. In this case study, i-Tree Eco procedures were found to be an effective and efficient tool, and provided valuable information regarding Auburn University’s urban forest structure and function. Key Words. i-Tree Eco; Tree Inventory; UFORE Model; Urban Forest Sampling, Urban Forestry. URBAN FORESTRY Volume 37, Issue 5, September 2011 Formerly the Journal of Arboriculture, 1975 – 2005 (Volumes 1 – 31) www.isa-arbor.com Anthony N. Mucciardi, Christoper J. Luley, and Kevin H. Gormally Preliminary Evidence for Using Statistical Classification of Vibration Waveforms as an Initial Decay Detection Tool ................................................................................................ 191 Abstract. Arborists commonly use sounding during an initial evaluation of urban trees to determine the presence of advanced decay and hol- lows. Striking the trunk with a mallet produces stress waves that propagate through the wood and, in turn, generate characteristic audible sounds. Successful application of this procedure, however, requires subjective evaluation of the sonic variations that result from differ- ent wood species and densities, and various ambient noise conditions. Therefore, a statistical classification approach was developed for auto- matically identifying decay from stress waves captured using an accelerometer probe that is less subjective and more reproducible than an operator-in-the-loop approach. The classification algorithms were designed to detect the presence of decay from aberrant characteristics of the vibration waveform and do not rely on sonic velocity changes commonly used in most sonic testing for decay. The approach was tested in a preliminary study on 36 segmented trunk samples representing a wide range of typical urban tree species and decay types. The clas- sifier successfully identified the decay status of 83% of the samples independent of species and trunk diameter. The results of this fea- sibility study cannot be transferred to real world tree inspection without additional testing on standing trees, but do demonstrate the poten- tial of using accelerometers supplemented with a statistical classifier to support an initial assessment of decay in urban trees by an arborist. Key Words. Accelerometer; Decay Detection; Feature Extraction; Pattern Classification; Sounding; Stress Waves; Urban Trees; Vibration Waves ©2011 | International Society of Arboriculture | ISSN:1935-5297
September 2011
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