IntroductionCOSTSAverage Annual Water and Irrigation Costs (W). Once planted, 15-gal trees typically require 100-200 gal (0.4-0.8 m3) per year during the establishment period. It is assumed that water was purchased at a price of $1.76 Ccf (Portland Water District 2001).Andrew Nguyen Benefit-Cost Analysis of Urban Landscaping Trees 05-09-05- p. 1 -A Benefit-Cost Analysis of Ten Urban Landscaping Trees in Berkeley, CAAndrew NguyenAbstract: A cost-benefit analysis was conducted for ten trees found in the City of BerkeleyInventory on urban forestry. Using models from previous analyses and studies, this studyquantified the ecological benefits of energy conservation potential, atmospheric CO2 reductions,air quality impacts and rainwater runoff in economic and monetary terms for each of the tenspecies of trees: London Plane Sycamore (Platanus acerifolia), Purple Leaf Plum (Prunuscerasifera), Liquidambar (Liquidambar styraciflua), Camphor (Cinnamomum camphora),Chinese Elm (Ulmus parvifolia), Oriental Cherry (Prunus serrulata), Victorian Box Pittosporum(Pittosporum undulatum), Shamel Ash (Fraxinus uhdei), English Elm (Ulmus procera), ModestoAsh (Fraxinus velutina glabra). These benefit values were then weighed against the direct costsof tree purchase, pruning, debris removal, tree removal and watering. From the benefit-costdifference, Camphor had the highest benefits across the board in terms of energy savings, carbonsequestration, and pollutant cycling and rainfall reductions, and hence should be used as apreferential tree for urban landscaping.Andrew Nguyen Benefit-Cost Analysis of Urban Landscaping Trees 05-09-05- p. 2 -IntroductionUrban forests are public investments that pay society back, enhancing the look, feel andvisual identity of communities, as well as improving environmental conditions through energyconservation, air pollution filtration, and stormwater runoff reduction. Good landscapingdecisions balance aesthetics and community values with economic factors such as the cost ofimplantation, maintenance and removal (Clark et al. 1997). The types of tree species and theirplanting locations in urban landscape are based on a number of factors, including species age anddiversity, growth requirements, site conditions, practicality, aesthetic appropriateness, and thehistoric and cultural context of the surrounding areas (Gilman 1997).Municipal urban forestry programs have sought to maintain, sustain, and enhance thecommunity’s forests through strategic landscape planning. Over the past 30 years, the City ofBerkeley’s Parks, Recreation, and Waterfront Department, for example, has actively planted over30,000 trees, 5,000 of which are located in parks and along local streets and roads (City ofBerkeley 2004). Under the Releaf Program of the city's Tree Policy and Tree Master Plan,Berkeley continues to plant over 800 trees a year on the streets, parks and public areas of the city(City of Berkeley 2004). However, Berkeley's municipal urban forestry programs may face newpressures in the near future due to financial constraints. As the State of California continues todeal with its budget woes, statewide funding for municipal redevelopment and public works mustbe constrained. Allocating resources for urban forestry tend to be lower priority when cities andcounties prioritize funding amongst competing needs. In this context, urban landscaping requiresmore cost-effective and efficient solutions to make wise use of limited funding.The purpose of this study is to provide a quantitative and qualitative comparison oflandscaping trees commonly used in Berkeley, to provide meaningful recommendationsregarding which species can maximize present and future economic benefits, in terms of bothdirect financial costs and ecological processes. This will simultaneously protect communityinterests and promote informed decisions about future urban forestry management. Whereasprevious landscaping decision making was motivated by aesthetic and personal preferenceissues, the economic analysis provided by this study will provide valuable statistical evidence forpreferential species planting in urban environments.This study analyzes tree suitability for urban forestry landscaping by looking at ten treespecies commonly planted in Berkeley and determining the tree species’ potential to conserveAndrew Nguyen Benefit-Cost Analysis of Urban Landscaping Trees 05-09-05- p. 3 -energy, reduce atmospheric CO2, and filter air pollutants. This study also evaluates total annuallandscaping and maintenance costs in terms of initial purchase, implantation, and maintenance,as well as watering costs.The following ten trees were selected for detailed evaluation in this study because they areamong the most abundant trees in Berkeley based on a 1990 street tree inventory (City ofBerkeley 2000):• Sycamore, London Plane (Platanus acerifolia)• Plum, Purple Leaf (Prunus cerasifera)• Liquidambar (Liquidambar styraciflua)• Camphor (Cinnamomum camphora)• Elm, Chinese (Ulmus parvifolia)• Cherry, Oriental (Prunus serrulata)• Pittosporum, Victorian Box (Pittosporum undulatum)]• Ash, Shamel (Fraxinus uhdei)• Elm, English (Ulmus procera)• Ash, Modesto (Fraxinus velutina glabra)Brief descriptions of each species’ ecology and characteristics can be found in Table 1. Mostof the above-listed species are ornamental trees, not native to the Berkeley area, but do well inthe region's Mediterranean-type climate and have characteristics suitable for street trees. Thesequalities include, but are not limited to, rapid growth, relatively low water maintenancerequirements, tolerance to various soil pHs and nutrient availability, non-serious pest attractants,and various aesthetic qualities, such as leaf and flower size and color.According to the City of Berkeley (2004) records, London Plane Sycamore (Platanusacerifolia) is one of the largest and also archetypal species of landscaping trees in the City ofBerkeley. An inventory by Thomas J. Pehrson in the late 1980s found P. acerifolia, as one of themost abundant species in the Berkeley area, constituting more than 29% of all trees in Berkeley.Also, it constitutes almost 23% of trees planted, the largest percentage of all others. Purple leafplum (Prunus cerasifera) is the second most urban landscaped tree in the city of Berkeleyconstituting 18% of all of those used for planting, and it already constitutes 22% of all trees inthe City of Berkeley. Since the
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