America's Covered Bridges. Ronald G. Knapp

      

      Hillsgrove, a hamlet nestled in Sullivan County, Pennsylvania’s Appalachian uplands, illustrates well the ephemeral character of timber bridges: the need for bridges to carry pedestrians, carriages, and railways; technological change and the replacement of materials; and the role of covered bridges in the “industrialization” of once heavily wooded areas. Constructed by Sadler Rogers in the 1850s, the wooden bridge on the left led directly into the settlement, while the taller railroad bridge brought timber-laden railcars to the odoriferous and polluting tannery, an industry that began in 1870 and lasted in Hillsgrove until 1924. As engines became larger, rail traffic increased, the industry flourished, and the wooden covered railway bridge was replaced by a “modern” iron truss bridge. Because tannin extracted from the bark of the bountiful hemlock trees in the area was used to produce leather from hides, a boom in population benefited this area. By 1890, 805 people inhabited Hillsgrove, but with the man-made development of acetone to replace tannin there was the following decline: 1900, 686; 1920, 273, and by 1930, 50 persons left. At the beginning of the twenty-first century, with a year-round population of about 70, the hamlet and surrounding area entice countless visitors to enjoy its reforested hillslopes, clean water, and fresh air. Branded as Pennsylvania’s Endless Mountains, locals take great pride in the three surviving covered bridges at Forksville, Hillsgrove, and Sonestown even as others are only recalled in memory and faded photographs. (Sullivan County Historical Society’s Museum)

      The longest historical covered bridge in the United States, the Cornish-Windsor Bridge (page 172), crosses the Connecticut River between New Hampshire and Vermont. On a heavily traveled route with a ten-ton load limit, the bridge carries two-way traffic day and night. In addition to ongoing maintenance to its Town lattice truss, extensive repairs have been carried out periodically since it was constructed in 1866. (A. Chester Ong, 2010)

      Blacksmith Shop Bridge, New Hampshire (page 171). (A. Chester Ong, 2010)

      Knight’s Ferry Bridge, California (page 248). (A. Chester Ong, 2012)

      Terry E. Miller and Ronald G. Knapp

       Photography by A. Chester Ong

      TUTTLE Publishing

       Tokyo Rutland, Vermont Singapore

      DEDICATION

      Terry’s father, Max T. Miller (1916–2009) of Dover, Ohio, provided the initial stimulus for investigating America’s covered bridges. The authors and photographer hereby dedicate this book to the memory of Max T. Miller.

      Published by Tuttle Publishing, an imprint of Periplus Editions (HK) Ltd

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      Text copyright © 2013 Terry E. Miller and Ronald G. Knapp Photographs copyright © 2013 A. Chester Ong

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       Front cover Spanning scenic Loyalsock Creek at Forksville (population 147) in Sullivan County in Pennsylvania’s northeast, the Forksville Bridge is one of the state’s most attractive covered bridges. Because it carries the relatively heavy traffic of Bridge Street going to and from SR 154, the state has hidden I-beams beneath the deck for safety and forestall replacement on the grounds of its official “inadequate” rating. The bridge was designed and constructed in the 1850s by Sadler Rogers, who created bridges large and small in the area. When yet a young man, he built a scale model of the rugged Burr truss that supports this 153-foot span. Although most of present-day Sullivan County (population under 7,000) is heavily forested, during the nineteenth century the hills and mountains were denuded by lumbermen, and vast quantities of hemlock logs were sent by raft down Loyalsock Creek under this bridge to the local tanneries. (A. Chester Ong, 2012)

       Back cover One of ten remaining covered bridges in California, the Bridgeport Bridge dates to 1862 (page 244). With the demise of New York’s Blenheim Bridge in 2011, this striking single-span Howe truss bridge with a clear span of 210 feet now has the greatest span of any bridge in the United States.

       Front flap Hillsgrove, a hamlet nestled in Sullivan County, Pennsylvania’s Appalachian uplands, illustrates well the ephemeral character of timber bridges: the need for bridges to carry pedestrians, carriages, and railways; technological change and the replacement of materials; and the role of covered bridges in the “industrialization” of once heavily wooded areas. Constructed by Sadler Rogers in the 1850s, the wooden bridge on the left led directly into the settlement, while the taller railroad bridge brought timber-laden railcars to the odoriferous and polluting tannery, an industry that began in 1870 and lasted in Hillsgrove until 1924. As engines became larger, rail traffic increased, the industry flourished, and the wooden covered railway bridge was replaced by a “modern” iron truss bridge. Because tannin extracted from the bark of the bountiful hemlock trees in the area was used to produce leather from hides, a boom in population benefited this area. By 1890, 805 people inhabited Hillsgrove, but with the man-made development of acetone to replace tannin there was the following decline: 1900, 686; 1920, 273, and by 1930, 50 persons left. At the beginning of the twenty-first century, with a year-round population of about 70, the hamlet and surrounding area entice countless visitors to enjoy its reforested hillslopes, clean water, and fresh air. Branded as Pennsylvania’s