Читать книгу North American Agroforestry - Группа авторов - Страница 16

The United States inherited its forest management practices from Europe during the latter part of the 19th century and modified them to accommodate its large, sparsely populated country, which was rich in natural resources (Perlin, 1991; Williams, 1989). Prior to settlement by Europeans, Native Americans derived a variety of food, forage, and fiber products from forests while manipulating them primarily through the use of fire in what could be termed landscape‐scale agroforestry (Carroll, 1973; Cronon, 1983; Rossier & Lake, 2014; Russell, 1982). European pioneers also derived most of their energy and construction materials from the forest (Carroll, 1973).

The Industrial Revolution brought with it new harvesting and milling technologies, which greatly enhanced the efficiency with which the nation’s forest resources were exploited (Williams, 1989). Such forest practices accelerated as the population grew and became more urbanized. Around the turn of the 19th century, continuing over‐exploitation stimulated public concern and the birth of America’s conservation movement (Jordan, 1994), which included the development of professional forestry management agencies and academic institutions (Skok, 1996; Spencer, 1996). In 1905, the U.S. Forest Service was formally established to promote sustained‐yield forestry, designed to provide wood fiber from the nation’s forests forever (Steen, 1976). Conflicts over the single‐purpose use of public forest lands led the U.S. Forest Service to develop its multiple‐use approach to the management of national forests, which assured that, given a large enough and diverse enough land base, a full complement of forest uses could be enjoyed without conflict. Eventually, however, this approach also led to problems once the public began to question decisions being made about individual pieces of land, especially with respect to tradeoffs between wilderness preservation and timber production (Nash, 1982). Such concerns, together with a growing understanding of the impacts that plantation forestry has on biological diversity and the natural functioning of forest ecosystems, have stimulated the forestry profession to consider a new management strategy—ecosystem management—based on a holistic, integrative approach to land use (Coufal & Webster, 1996; Maser, 1994; Nunez‐Mir, Iannonne, Curtis, & Fei, 2015; Probst & Crow, 1991; Stankey, 1996). Parallel to those efforts and because of the growing interest in preserving our national forests free from production activities, national forests are increasingly off limits to harvest, shifting production forestry and harvesting to private lands (Adams, Haynes, & Daigneault, 2006). Simultaneously, there is a growing public cry for less governmental regulation and a return to a conservation ethic embodied in the idea of sound stewardship (Jordan, 1994). Likewise, it took a century and a half for American agriculture to develop to the level of complexity that required an integrated management approach (National Research Council, 1989). Native Americans were hunter‐gatherers, subsistence farmers, and also practiced indigenous forms of landscape‐scale agroforestry (Rossier & Lake, 2014), while early immigrants were primarily hunter‐gatherers and subsistence farmers (Russell, 1982). With population growth and industrial development came a growing need to improve food production capabilities and economic livelihoods of farmers to feed an ever‐increasing urban society. The mid‐1800s brought the development of the land grant university system and the initiation of an agricultural experiment station infrastructure that eventually built the world’s greatest system for the intensive cultivation of commercial food products (National Research Council, 1996; Russell, 1982).

Domestic and global marketing uncertainties, high costs for equipment, seed, chemical and energy inputs, high interest rates, and regional identity and security issues are forcing many modern farmers to develop integrated farming systems involving the production of a variety of products. More recent public concerns about the environmental impacts of modern farming practices and food safety are prompting the development of a new management approach based on agroecology principles: alternative or sustainable agriculture (LaCanne & Lundgren, 2018; Liebman & Schulte, 2015; National Research Council, 1989, 1991, 1996) More recently, eco‐agriculture and regenerative agriculture—integrating production and conservation at a landscape scale with the deliberate inclusion of perennial crops—have been put forth as new paradigms for linking production and conservation in our agricultural landscapes (Elevitch et al., 2018; Scherr & McNeely, 2007, 2008). Perennial trees and shrubs, and hence agroforestry practices, can serve important functions in such sustainable agricultural systems (Elevitch et al., 2018; Prinsley, 1992).