Hutyra, Lucy R.; Yoon, Byungman; Hepinstall-Cymerman, Jeffrey; Alberti, Marina. (2011). Carbon Consequences of Land Cover Change and Expansion of Urban Lands: A Case Study in the Seattle Metropolitan Region. Landscape And Urban Planning, 103(1), 83 – 93.
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Abstract
Understanding the role humans play in modifying ecosystems through changing land cover is central to addressing our current and emerging environmental challenges. In particular, the consequences of urban growth and land cover change on terrestrial carbon budgets is a growing issue for our rapidly urbanizing planet. Using the lowland Seattle Statistical Metropolitan Area (MSA) region as a case study, this paper explores the consequences of the past land cover changes on vegetative carbon stocks with a combination of direct field measurements and a time series of remote sensing data. Between 1986 and 2007, the amount of urban land cover within the lowland Seattle MSA more than doubled, from 1316 km(2) to 2798 km(2), respectively. Virtually all of the urban expansion was at the expense of forests with the forested area declining from 4472 km(2) in 1986 to 2878 km(2) in 2007. The annual mean rate of urban land cover expansion was 1 +/- 0.6% year(-1). We estimate that the impact of these regional land cover changes on aboveground carbon stocks was an average loss of 1.2 Mg C ha(-1) yr(-1) in vegetative carbon stocks. These carbon losses from urban expansion correspond to nearly 15% of the lowland regional fossil fuel emissions making it an important, albeit typically overlooked, term in regional carbon emissions budgets. As we plan for future urban growth and strive for more ecologically sustainable cities, it is critical that we understand the past patterns and consequences of urban development to inform future land development and conservation strategies. (C) 2011 Elsevier B.V. All rights reserved.
Keywords
Sprawl; Growth; Carbon Cycle; Emissions; Land Cover; Urbanization; Seattle; Vegetation; Carbon; Carbon Sinks; Case Studies; Cities; Ecosystems; Forests; Fossil Fuels; Humans; Land Use; Planning; Remote Sensing; Time Series Analysis
Karvonen, Andrew; Yocom, Ken. (2011). The Civics Of Urban Nature: Enacting Hybrid Landscapes. Environment & Planning A, 43(6), 1305 – 1322.
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Abstract
Urban nature is typically managed through top-down, bureaucratic, and expert-driven approaches that tend to rationalize and simplify the interactions between humans and their surroundings. In the last few decades, there has been a significant push in cultural geography and the design disciplines to develop a relational ontology of urban nature, a perspective that emphasizes the hybrid connections between humans and nonhumans, built and unbuilt, social and natural. This perspective offers new and exciting ways of conceptualizing urban nature but it has not produced alternatives to conventional governance. In other words, thinking differently about urban nature has yet to produce different ways of interacting with it. In this paper we argue that civic environmentalism can enact a relational ontology by engaging urban residents in processes of democratic deliberation and action in the reworking of urban nature. We illustrate this approach with a case study of a community-led project to construct a pedestrian trail along an urban creek in Seattle, Washington. The example demonstrates how the concept of civic environmentalism embraces a relational perspective of urban nature, while also producing generative forms of political action.
Keywords
Cities & Towns; Ontology; Deliberation; Environmentalism; Trails; Rivers; Washington (state); Seattle (wash.)
Kim, Yong-Woo; Han, Seungheon; Shin, Sungwon; Choi, Kunhee. (2011). A Case Study of Activity-Based Costing in Allocating Rebar Fabrication Costs to Projects. Construction Management And Economics, 29(5), 449 – 461.
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Abstract
How to improve cost allocation for reinforced steel bar (rebar) is an ongoing topic of debate among construction manufacturers and contractors. Traditionally, many fabrication shops have used a single overhead-cost pool accounting system. However, a new costing method, activity-based costing (ABC), may provide more advantages than the traditional system. In this case study, a single overhead-cost pool system is compared with the ABC method to demonstrate how ABC improves cost allocation and provides other benefits. The case study findings indicate that ABC provides such benefits as (1) accurate manufacturing costs; (2) cost information on processes; and (3) information on cost drivers. This paper also bridges the construction and cost accounting literature. Our study contributes to the construction management literature by offering a different cost allocation method to refine fabrication costs assigned to projects. The findings are expected to serve as a reference for industry professionals who recognize the shortcomings of a traditional single overheadcost pool system and are in need of a more accurate costing system. © 2011 Taylor & Francis.
Keywords
Bridges; Costs; Fabrication; Lakes; Project Management; Rebar; Accounting System; Activity Based Costing; Construction Management; Fabrication Shops; Industry Professionals; Manufacturing Cost; Overhead Costs; Traditional Systems
Liu, Chao; Shen, Qing. (2011). An Empirical Analysis of the Influence of Urban Form on Household Travel and Energy Consumption. Computers, Environment & Urban Systems, 35(5), 347 – 357.
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Abstract
Using the 2001 National Household Travel Survey (NHTS) data, this paper empirically examines the effects of urban land use characteristics on household travel and transportation energy consumption in the Baltimore metropolitan area. The results of regression analysis show that different built environment measures lead to substantially different findings regarding the importance of urban form in influencing travel behavior. Among the built environment variables used in the analysis, accessibility provides much more explanatory power than density, design and diversity measures. Moreover, this study explores approaches to modeling the connection between urban form and household transportation energy consumption. Applying Structural Equation Models (SEMs), we found that urban form does not have a direct effect either on VMT or on vehicle energy consumption. The indirect effect, however, is significant and negative, which suggests that urban form affects household travel and energy consumption through other channels. In addition, household socio-economic characteristics, such as gender and number of vehicles, and vehicle characteristics also show significant relationships between VMT and energy consumption. This empirical effort helps us understand the major data and methodology challenges. (C) 2011 Elsevier Ltd. All rights reserved.
Keywords
Urban Planning; Households; Travel; Energy Consumption; Empirical Research; Transportation; Metropolitan Areas; Climate Change; National Household Travel Survey (nhts); Usage; Environment; Behavior; Holdings; Impact
Moudon, Anne Vernez; Cook, Andrea J.; Ulmer, Jared; Hurvitz, Philip M.; Drewnowski, Adam. (2011). A Neighborhood Wealth Metric for Use in Health Studies. American Journal Of Preventive Medicine, 41(1), 88 – 97.
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Abstract
Background: Measures of neighborhood deprivation used in health research are typically based on conventional area-based SES. Purpose: The aim of this study is to examine new data and measures of SES for use in health research. Specifically, assessed property values are introduced as a new individual-level metric of wealth and tested for their ability to substitute for conventional area-based SES as measures of neighborhood deprivation. Methods: The analysis was conducted in 2010 using data from 1922 participants in the 2008-2009 survey of the Seattle Obesity Study (SOS). It compared the relative strength of the association between the individual-level neighborhood wealth metric (assessed property values) and area-level SES measures (including education, income, and percentage above poverty as single variables, and as the composite Singh index) on the binary outcome fair/poor general health status. Analyses were adjusted for gender, categoric age, race, employment status, home ownership, and household income. Results: The neighborhood wealth measure was more predictive of fair/poor health status than area-level SES measures, calculated either as single variables or as indices (lower DIC measures for all models). The odds of having a fair/poor health status decreased by 0.85 (95% CI=0.77, 0.93) per $50,000 increase in neighborhood property values after adjusting for individual-level SES measures. Conclusions: The proposed individual-level metric of neighborhood wealth, if replicated in other areas, could replace area-based SES measures, thus simplifying analyses of contextual effects on health. (Am J Prev Med 2011; 41(1): 88-97) (C) 2011 American Journal of Preventive Medicine
Keywords
Health -- Social Aspects; Social Status; Public Health Research; Home Ownership; Income; Real Property; Deprivation (psychology); Health Education; Disparities Geocoding Project; Body-mass Index; Socioeconomic-status; Ecological Fallacy; Built Environment; Deprivation Indexes; Multilevel Analysis; Individual-level; Social-class; Inequalities