Past, present, and future old growth in frequent-fire conifer forests of the Western United States

Abella, Scott R. and Covington, W. Wallace and Fule, Peter Z. and Lentile, Leigh B. and Meador, Andrew J. Sánchez and Morgan, Penelope (2007) Past, present, and future old growth in frequent-fire conifer forests of the Western United States. Ecology and Society, 12 (2). 16 [online]. ISSN 1708-3087

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Abstract

Old growth in the frequent-fire conifer forests of the western United States, such as those containing ponderosa pine (Pinus ponderosa), Jeffrey pine (P. jeffreyi), giant sequoia (Sequioa giganteum) and other species, has undergone major changes since Euro-American settlement. Understanding past changes and anticipating future changes under different potential management scenarios are fundamental to developing ecologically based fuel reduction or ecological restoration treatments. Some of the many changes that have occurred in these forests include shifts from historically frequent surface fire to no fire or to stand-replacing fire regimes, increases in tree density, increased abundance of fire-intolerant trees, decreases in understory productivity, hydrological alterations, and accelerated mortality of old trees. Although these changes are widespread, the magnitude and causes of changes may vary within and among landscapes. Agents of change, such as fire exclusion or livestock grazing, likely interacted and had multiple effects. For example, historical ranching operations may have altered both fire regimes and understory vegetation, and facilitated institutional fire exclusion through fragmentation and settlement. Evidence exists for large variation in presettlement characteristics and current condition of old growth across this broad forest region, although there are many examples of striking similarities on widely distant landscapes. Exotic species, climate change, unnatural stand-replacing wildfires, and other factors will likely continue to degrade or eradicate old growth in many areas. As a policy of fire exclusion is proving to be unsustainable, mechanical tree thinning, prescribed fire, or wildland fire use will likely be key options for forestalling continued eradication of old growth by severe crown fires. For many practical and societal reasons, the wildland—urban interface may afford some of the most immediate opportunities for re-establishing old growth typical of presettlement forests resistant to crown fires.

Item Type:	Article
Publisher’s Statement:	Copyright © 2007 by the author(s).
Keywords:	afforestation; Agriculture; black-hills; Colorado front range; droughts; Ecological restoration; environmental policy; evolutionary environment; forests & forestry; giant sequoia forest; government policy; lake tahoe basin; landscapes; management; mixed conifer; montane forests; national-park; natural disasters; Natural resources; Pinus jeffreyi; Pinus Ponderosa; ponderosa pine forests; range of variability; san-juan mountains; Sequoia giganteum; sierra-nevada; tree crops
Subjects:	S Agriculture > SD Forestry
NAU Depositing Author Academic Status:	Faculty/Staff
Department/Unit:	Research Centers > Ecological Restoration Institute College of Engineering, Forestry, and Natural Science > School of Forestry
Date Deposited:	16 Oct 2015 18:33
URI:	http://openknowledge.nau.edu/id/eprint/660

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