Showing papers by "W. Wallace Covington published in 2000"

Helping western forests heal.

Abstract: whacking’ and forest burning that will only exacerbate the problem. I am not so naïve as to believe that science will drive the entire debate. But, having spent 25 years trying to advance the need for ecosystem restoration, I know that debate descends to paralysis when it begins with ideology. In the little time left, it is imperative that fuels treatments should be driven by ecological restoration principles; that scientists should actively inform the debate; that scientists, managers and the public should not be afraid to use what we currently know to identify restoration treatments; that all restoration should be conducted in an explicitly formal, adaptive management context; and that multiple approaches should be tested and carefully monitored.

Ponderosa pine ecosystems restoration and conservation: steps toward stewardship; 2000 April 25-27; Flagstaff, AZ

Abstract: This volume is divided into three sections: (1) Ecological, Biological, and Physical Science; (2) Social and Cultural; and (3) Economics and Utilization. Effective ecological restoration requires a combination of science and management. The authors of the first section exemplified this integration in the course of addressing a broad range of topics, from detailed microsite and small-scale changes in fungal, plant, and animal communities, up through landscape, regional, and subcontinental scales. Although the themes were diverse, papers were linked by underscoring the relationship between restorative management actions and ecological effects. Social sciences play a key role in ecosystem restoration because collaboration, development of common goals, and political and economic feasibility are essential for success. The authors of the second section focused on public attitudes, partnerships, and the relationship between social and ecological factors. In the third section, the economics and utilization of products from forest restoration were compared in several Western locations. Both the markets for these products and the range of utilization opportunitiesfrom small-diameter logs to energy creationwill surely evolve rapidly as society moves to address the fire hazards and other problems caused by stressed and weakened ecosystems. The turn of the century is an appropriate point to capture dramatic changes in perspective: consider how attitudes toward Western forests have evolved between 1900 and 2000. The papers in this volume chronicle adaptive research that continues to deepen our understanding of restoration in ecosystems and social systems.

Effects of an intense wildfire in a Mexican oak-pine forest.

Abstract: An oak-pine forest burned by intense wildfire in April, 1996, and a companion unburned area were sampled 1 month and 1 yr postfire in La Michilia Biosphere Reserve, Durango, Mexico. Up to 90% of the trees were killed or top-killed in the burned area, but larger trees tended to survive, so basal area was only reduced by 66%. Top-killing was relatively higher among fire-susceptible oaks and lower among fire-resistant pines. However, oaks were strong resprouters both in the canopy and at the base of top-killed trees. Damage codes based on crown scorch and bole charwere highly accurate when predicting that a tree would die but substantially overestimated survivors. Most tree regeneration was top-killed in the fire, but oak sprout density was 700% that of the unburned area by 1 yr postfire. Manzanita shrubs also resprouted vigorously. Herbaceous production and cover were lower after the first postfire growing season in the burned area than the unburned area. Woody fuels and forest floor depth were also reduced. Although short-term fire effects indicate that the forest ecosystem has moved closer toward a savanna condition, remnant seed trees and sprouting trees are expected to maintain forest cover. Future herbaceous production is likely to increase in response to overstory mortality. Quantification of fire effects is helpful for supporting short-term management decisions since oak-pine forests cover millions of hectares in northern Mexico. As a long-term management strategy, however, we suggest that restoring the frequent, low-intensity fire regime may be desirable for ecological and economic reasons.

Continuing fire regimes in remote forests of Grand Canyon National Park.

Abstract: Ponderosa pine forests in which frequent fire regimes continue up to the present would be invaluable points of reference for assessing natural ecological attributes. A few remote forests on the North Rim of Grand Canyon National Park come close to this ideal: never-harvested, distant from human communities and fire suppression resources, and with several low-intensity fires in the past century—a highly unusual recent fire regime in the Southwest. Recent fires appear to have played a crucial role in preventing the increases in forest density that characterize most southwestern pine forests. The study sites are not unaffected by the ecological changes associated with settlement, but they do present an impor- tant reference resource for study and management of ponderosa pine ecosystems. Ponderosa pine forests in which historically frequent fire regimes continue up to the present would be invaluable points of reference for assessing natural attributes of eco- logical structure and function. Grand Canyon National Park contains one of the largest old-growth forests in the South- west, where tree harvesting has not occurred and grazing has been eliminated for over 60 years. Although most fire disturbance regimes in the park have been disrupted since European settlement, a few remote sites may retain near- natural conditions. The majority of the forested area lies on the North Rim, part of the Kaibab Plateau, which supports ponderosa pine, mixed conifer and spruce-fir forests at elevations ranging from 7,500 to 9,165 feet on well-drained limestone soils. The North Rim is remote from modern human communi- ties, but Altshul and Fairley (1989) document the long human history of the region. The lower elevations of the rim were densely populated by Native Americans prior to 1250-1300 A.D. Six tribes—the Paiute, Hopi, Havasupai, Hualapai, Navajo, and Zuni—have ancestral and current connections to the canyon and rim habitat. An expedition led by the Spaniards Dominguez and Escalante in 1776 marked the first European presence on the Arizona Strip, the land north of the Colorado River that includes the

Development of ecological restoration experiments in fire adapted forests at Grand Canyon National Park.

Abstract: The management of national park and wilderness areas dominated by forest ecosystems adapted to frequent, low-intensity fires, continues to be a tremendous challenge. Throughout the inland West and particularly in the Southwest, ponderosa pine (Pinus ponderosa) and mixed conifer forests have become dense and structurally homogeneous after periods of intense livestock grazing, followed by more than 100 years of fire suppression. Prior to the late 1800s, pine-dominated forests at Grand Canyon National Park were structurally diverse, averaging 45 to 90 trees per acre, with frequent, low-intensity fires burning across the landscape every 7 to 11 years. Today, much of the historic landscape heterogeneity has been replaced by dense, contiguous stands averaging 600 to 900 trees per acre. The beneficial reintroduction of fire to these areas is difficult and often results in fire effects that are uncharacteristic of those produced by historic fire regimes. In response, park managers have called for the exploration of restoration approaches using combinations of prescribed fire and understory thinning. The goal of this approach is to achieve more natural and sustainable forest structures while conserving the most fragile elements of the exist- ing ecosystem such as old-growth trees and native herbaceous communities. This paper describes the approach, rationale and preliminary results of a project designed to examine the utility and ecological effects of three, small-scale restoration experiments on a suite of forest structure attributes. homogenized landscapes, and now provide a conduit for the development of large-scale, high intensity fires (GRCA 1992; Moore 1994; Nichols and others 1994). Recent at- tempts to reintroduce fire into these dense forests have been costly to prepare, difficult to control and often produce damaging fire effects, particularly in mixed conifer forests on the North Rim of the Park (Nichols and others 1994). The most notable effect of these high intensity fires is a marked loss of old-growth trees due to excessive crown scorch and pockets of stand replacing fire. These effects are of particular concern since Grand Canyon National Park contains some of the largest remaining tracts of unhar-