Landscape and Urban Planning 71 (2005) 51–72 Twenty-five years of sprawl in the Seattle region: growth management responses and implications for conservation Lin Robinson a,∗ , Joshua P. Newell b , John M. Marzluff a a College of Forest Resources, Anderson Hall, P.O. Box 352100, University of Washington, Seattle, WA 98195-2100, USA b Department of Geography, University of Washington, Seattle, WA 98195, USA Received 26 November 2002; received in revised form 7 September 2003; accepted 16 February 2004 Abstract To study the effects of growth management efforts on urban fringe areas in Washington State’s Puget Sound region, USA, this study documents and quantifies transformations in land cover and land-use from 1974 to 1998 for a 474 km 2 study area east of Seattle. Geo-referenced aerial photographs (orthophotos) were digitized, then classified, to compare patch patterns (clustered versus dispersed vegetation, remnant versus planted vegetation), size, development type (single-family housing, multi-family housing, commercial) and percent vegetative cover between 1974 and 1998 images. Changes in interior forest habitat and amount of edge were also calculated. The study showed that suburban and exurban landscapes increased dramatically between 1974 and 1998 at the expense of rural and wildland areas. Settled lands became more contiguous while rural and wildland areas became more fragmented. Interior forest habitat in wildland areas decreased by 41%. Single-family housing was the primary cause of land conversion. Current growth management efforts prioritize increasing housing density within urban growth boundaries (UGBs), while limiting densities outside these boundaries. The study demonstrated that housing density has indeed increased within these boundaries, but at the same time, sprawling low-density housing in rural and wildland areas constituted 72% of total land developed within the study area. Therefore, policies to reduce the density of settlement outside urban centers, in part to protect ecological systems, may have unintended environmental consequences. This has implications for those urban areas, both in the United States and in other countries, considering growth management strategies. © 2004 Elsevier B.V. All rights reserved. Keywords: Edge; Forest conversion; Growth management policy; Habitat fragmentation; Landscape patterns; Low-density housing; Sprawl; Urban growth boundaries 1. Introduction “Sprawl” is a relatively new pattern of human set- tlement characterized by a haphazard patchwork of low-density housing and commercial strip develop- ment created by and dependent on extensive auto- mobile use (Ewing, 1997; Gillham, 2002). Sprawl typically moves away from existing settlement in a ∗ Corresponding author. Tel.:+1-206-362-1293. E-mail address: linrobin@u.washington.edu (L. Robinson). “leap-frog” pattern, as widely spaced developments initially occur several kilometers from the central business district and later become connected by in- fill development. In the early 20th century, urban populations in the United States were concentrated within cities, but by the 1960s, this pattern began to change. During the 1970s and 1980s, more than 95% of US population growth took place in subur- ban areas outside cities (Gillham, 2002). Today, in the US, more people live and work in suburbs than in cities. As a result, sprawl has emerged as the 0169-2046/$20.00 © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.landurbplan.2004.02.005