Ecological Restoration of Southwestern Ponderosa Pine Forests

Peter Friederici, Peter Ecological Restoration Institute, Peter Friederici, Peter Ecological Restoration Institute

• Publisher: Island Press
• Year: 2013
• Print ISBN: 9781559636537, 9781559636520
• eBook ISBN: 9781597262965
• Subtopic: Ecology

Ecological Restoration of Southwestern Ponderosa Pine Forests brings together practitioners and thinkers from a variety of fields—including forestry, biology, philosophy, ecology, political science, archaeology, botany, and geography—to synthesize what is known about ecological restoration in ponderosa pine forests and to consider the factors involved in developing and implementing a successful restoration effort. The book examines:

• the overall context for restoration—ecological, social, economic, political, and philosophical
• how ecosystem processes such as fire, hydrology, and nutrient cycling are affected by restoration activities
• treatment effects on specific ecosystem components such as trees, understory plants, animals, and rare or invasive species
• the details of implementing restoration projects, including smoke management, the protection of cultural resources, and monitoring

Each section is introduced with a case study that demonstrates some of the promise and pitfalls of restoration projects.

Ecological Restoration of Southwestern Ponderosa Pine Forests is the second book in the series The Science and Practice of Ecological Restoration from the Society for Ecological Restoration International and Island Press.

PART I

The Context for Restoration

Ecological restoration has as its goals the preservation of biodiversity, the health and maintenance of sustainable ecosystems, and the development of mutually beneficial relationships between humans and nature. In some instances, though, it is perceived as a specialized endeavor that remains primarily of interest to its practitioners—something yet to be fully understood by society’s mainstream. In southwestern ponderosa pine forests, restoration is more than this. Ecological restoration of these forests is intimately tied to human well-being, and is of concern to wide segments of society. Many southwestern forests that are ecologically unhealthy are also uncommonly prone to dangerous, high-intensity fires. Restoration has the potential to simultaneously return ecological integrity and reduce the risk of such fires. As described in Chapter 1, a large-scale restoration project in Flagstaff, Arizona, was designed precisely with those goals in mind.

But Chapter 1 also shows that these efforts can be controversial and difficult to implement. Why should this be so? It is not, for the most part, any failing of science. Wally Covington, in Chapter 2, demonstrates that the ecological functioning of these forests (Figure I.1) is fairly well understood. An arid climate and long-lived trees have allowed researchers, through the study of tree rings and other physical evidence, to reconstruct forest history in great detail. In many cases we know what their structure once was; we know how often they burned; we know to what extent such disturbances were correlated with climate cycles or aspects of human history; we know how long their trees lived. We also know how they have changed since the advent of modern, Western civilization. To a remarkable extent we know what these forests were like, in other words, in the period immediately preceding Euro-American settlement, the last period during which processes that shaped these ecosystems over evolutionary time remained intact. Soon after Euro-American settlement, novel cultural practices such as heavy livestock grazing and fire suppression were introduced, with severe impacts on forest structures and ecological processes.

Of course, any study of physical reference materials is inevitably limited. As Thom Alcoze shows in Chapter 3, the dendrochronological record does not clearly reveal to what extent indigenous peoples altered fire regimes in southwestern ponderosa pine forests, but native peoples and nonhuman forces do appear to have worked in ecological concert; fires caused by people and by lightning, in other words, had similar ecological effects. It is beyond the scope of this book to argue whether this was due to low population numbers, limited technologies, or particular worldviews; the important point is that prior to the arrival of Euro-Americans, human influences on the ecology of southwestern ponderosa pine forests appear to have remained well within what has been labeled their “historic range of variation.”

Figure I.1. Powell Plateau, Grand Canyon National Park, northern Arizona. Widely spaced pines and a well-developed herbaceous understory constitute conditions that were once widespread but are now rare in southwestern ponderosa pine forests. Photograph by Doc Smith/Ecological Restoration Institute.

Chapter 2 discusses the evolutionary context of southwestern pine forests and reviews the enormous changes that have taken place since the arrival of Euro-Americans. Though logging has had the most visible short-term effect on forest structure, it can be argued that livestock grazing and fire suppression have had more insidious long-term effects, since they have fundamentally altered forest processes . Today, though primary resource exploitation plays a relatively minor role in the economy of the Southwest, the pressures of human uses on these forests have grown and will likely continue to grow in manifold ways, complicating the planning and implementation of restoration treatments or of any other management strategy.

Restoration has the potential to solve some, though certainly not all, of the problems current forest managers face. And science certainly has a primary role to play in informing restoration decisions. But it is important to note that many past decisions that helped create today’s forest conditions—such as the suppression of wildfires—were also informed by scientific understanding. How is restoration ecology different from past science? Why should we trust it?

A partial answer is this: Unlike many past uses of science, restoration ecology is not driven by economics. As P. J. Daugherty and Gary Snider write in Chapter 4, it may dovetail both with the wish to protect human habitations from wildfire and in some cases with commercial activities, but it does not exist for those reasons. It may eventually produce economic payoffs in the form of reduced fire-fighting expenditures, but in the short term society will have to pay to implement it. Restoration does not, unlike many traditional management practices, seek profits by extracting resources more quickly than the ecosystem can sustainably produce them. It seeks to work with natural processes, rather than against them.

The science of restoration ecology also cannot be divorced from its social context. Restoration is not and cannot be just about ecology. It is intimately tied to the sorts of economic decisions that have played a role in bringing the forests to their current degraded condition (Chapter 4); it is an artifact of the decision-making processes that shape a democratic society (Chapter 5); and it is linked to the ways in which human beings see the world and define their social roles (Chapter 6). Restoration, then, is not just a matter of refining our ecological knowledge and using it to inform management decisions. It is a matter of redefining relationships both among human beings and between humans and nature. It will succeed only if, as Daugherty and Snider argue, economic relationships are forged that value sustainable, multigenerational human links to our natural surroundings; if decisions are reached, as Hanna Cortner argues, through truly democratic and inclusive processes; and if all participants in these forests, as Max Oelschlaeger argues, see themselves as part—but only as a part—of what he terms the larger “forest story.”

Compromise on all sides would seem to be in order. If restoration is to succeed on a large scale, across the landscape, loggers will have to accept the reality that any sustainable forest industry in the Southwest must be based on the harvest of small, rather than large, trees; environmentalists will have to accept that, whatever the sorry story of human intervention in the last century, there is a role for people in the ecology of the region’s forests; agency officials will have to accept that their decisions must be made with a full range of truly meaningful public input; scientists will have to accept that their findings alone are not sufficient for informed decision-making. It will be the better part of wisdom if we all can accept that such compromises, which might at first appear to be limitations, are really strengths: they argue for an intimate, thoughtful, and mutualistic relationship between people, other members of the community of organisms, and their natural surroundings. These are not matters for ecologists or for professional land managers alone; they are matters for us all.

Chapter 1

The “Flagstaff Model”

PETER FRIEDERICI

Flagstaff, Arizona, a rapidly growing city of more than 50,000, is nestled in the largest ponderosa pine forest in the world, a swath of trees that extends from western New Mexico to north-central Arizona. The sharp-edged San Francisco Peaks, thickly cloaked with pine, fir, spruce, and aspen, rise high on the northern skyline. It’s a beautiful setting, but also a flammable one. Several times in recent years large wildfires have cast palls of smoke over the city and made residents cognizant of the danger inherent in living in a fire-prone forest.

It is because the residents of Flagstaff both love their trees and fear wildfires that they have launched an ambitious campaign to restore the surrounding forest. This effort is being closely watched in other communities because of the controversy it has engendered, and because federal officials have pointed to the “Flagstaff Model” as a template for cooperative restoration efforts elsewhere (Jehl 2000). The primary focus of restoration activities in the Flagstaff area is the Greater Flagstaff Forests Partnership (GFFP), a collaborative effort that has as its goal the restoration of 100,000 acres (40,000 hectares) of forest ringing the city. It is an ambitious plan that illustrates both the potential for forest restoration and its pitfalls, and that raises questions highly applicable to restorationists elsewhere, especially: if this is such a good idea, why is it so hard to implement?

“The Finest Timber in the World”

Flagstaff is an appropriate hub of forest restoration, since the extractive excesses that have altered southwestern forests were unbridled here. As Euro-American settlement of northern Arizona began in the 1870s, the area’s resources were rich and accessible. Ponderosa pine trees towered over bunchgrasses in open, sunny forests. Old trees developed conspicuous yellow bark and grew to a meter and more in diameter. In 1876 one visitor, George Brewer, wrote that these so-called yellow pines constituted a “very extensive belt of the finest timber in the world” contiguous to the city’s site (Cline 1976).

In 1882 Flagstaff’s first sawmill opened, with the primary purpose of producing supplies for the new transcontinental Atlantic & Pacific Railroad. The rails allowed easy shipping, and in 1883 alone the mill produced 20 million board feet (47,200 square meters) of what was described as “magnificent clear lumber” (Hamilton 1884) and shipped as far east as New York (Ashworth 1991). Other sawmills followed, and logging of old-growth pines (Figure 1.1) continued as a significant industry into the late twentieth century.

Logging was conducted through clearcutting in the early days, and entire mile-square sections were laid bare (Ashworth 1991; Menzel and Covington 1997). Even after the San Francisco Mountain Forest Reserve, a forerunner of northern Arizona’s national forests, was established in 1898, with regulations requiring the retention of “seed trees,” few old trees were left. On Woody Mountain, southwest of Flagstaff, loggers cut an estimated 3,000 to 4,000 pines with an average diameter at breast height (dbh) of 20 inches (51 centimeters) in 1904, and on more than 450 acres (180 hectares) left only 64 seed trees (Ashworth 1991). In 1904 a United States Geological Survey report predicted that the area’s “[c]losely logged lands will not again bear a forest equal to the one cut off during the next 220 to 250 years” (Leiburg et al. 1904).

Figure 1.1. Getting out the yellow pines: logging near Flagstaff, circa 1926. Photograph courtesy of Arizona Historical Society/Northern Arizona Division, AHS.0688.00004.

Newcomers also quickly took advantage of what one explorer called the region’s “luxuriant” and “abundant” bunchgrasses (Beale 1858). By 1887 an estimated 200,000 sheep grazed the San Francisco Peaks area (Cline 1976). Ranchers imported huge herds of cattle, and by 1888 a Prescott newspaper reported that “many portions of the [Arizona] Territory are now overstocked to an alarming extent” (Cline 1976). Severe drought in 1891 and 1892 killed livestock in droves. Ranchers went broke, and long-term damage was done to rangelands around Flagstaff, across northern Arizona, and throughout the Southwest (Leiburg et al. 1904; Baker et al. 1988; Abruzzi 1995). Cattle and to a lesser extent sheep grazing continue at a much smaller scale today.

Wildlife populations also changed dramatically. Grizzly bears (Ursus arctos horribilis) and gray wolves (Canis lupus) were extirpated in the first half of the twentieth century. Merriam’s elk (Cervus elaphus merriami), which were scarce or absent during the nineteenth century, were driven to extinction early on (Davis 1982); Rocky Mountain elk (C. e. nelsoni), a different subspecies, were introduced in the first half of the twentieth century and have proliferated; pronghorn (Antilocapra americana), meanwhile, have grown much scarcer (Davis 1982). Heavy grazing and browsing by elk and mule deer (Odocoileus hemionus) have almost certainly helped alter the forest’s herbaceous understory.

The area’s forests changed quickly. Tree-ring analysis has shown that pines in Fort Valley, 10 miles northwest of Flagstaff, burned at average intervals of between 4.4 and 17 years (Dieterich 1980), consistent with the 2- to 8-year fire interval found at many sites in northern Arizona (Moore et al. 1999). These fires raced through the flammable grasses and killed some small trees but rarely burned the crowns of large pines (Woolsey 1911; Cooper 1960). The last significant fire in Fort Valley, as in Walnut Canyon just east of Flagstaff, was recorded in 1876 (Dieterich 1980; Swetnam et al. 1990); the last at Camp Navajo west of Flagstaff occurred in 1883 (Fulé et al. 1997). Logging slash fueled fires even in logged areas, though, and as early as 1885 loggers and sawmill crews were sent to fight forest fires near Flagstaff (Ashworth 1991), while Forest Service firefighters were organized in the early twentieth century.

By the beginning of the twentieth century, concerns about deforestation and overgrazing had grown. The establishment of forest reserves and the U.S. Forest Service was one result; so was the beginning of a more rigorous forest science. In 1908 forester Gus Pearson helped found the first forest experiment station on federal land in Fort Valley. With Theodore Woolsey, he also established permanent forest plots in northern Arizona and New Mexico, to be remeasured at five-year intervals (Woolsey 1911).

Pearson’s first assignment was to ascertain why ponderosa pine was not reproducing in cutover areas: partly, he found, because loggers had left few seed trees, and partly because in the Southwest few years are wet enough to allow widespread survival of ponderosa seedlings. He and other foresters were relieved when one such year came in 1919 (Pearson 1923). Growing conditions that year were further enhanced by a grazing-induced lack of competition from grasses, and by a lack of low-level fires that might have killed seedlings.

The cumulative result of these changes was profound. Within a century the forest around Flagstaff was first open and composed largely of big pines and bunchgrasses; then denuded of large trees and severely overgrazed; and finally composed primarily of dense thickets of young pines, many of them established in 1919. A typical example is close at hand to the experimental station Pearson established. In the Gus Pearson Natural Area, an unlogged stand whose trees have been measured at five-year intervals since 1920, a reconstruction of 1876 forest conditions conducted in the 1990s resulted in striking comparisons (Covington et al. 1997). Where an average of 22.8 pines per acre (56 per hectare) had grown in small clumps in 1876, more than 1,250 per acre (3,000 per hectare) grew in continuous stands in the 1990s. More than 98 percent were smaller than 16 inches (40 centimeters) in diameter, and many formed dense “doghair” thickets of small trees. Buried in accumulated dead needles, the forest floor supported scant understory vegetation.

Throughout the re...

Table of contents

• ABOUT ISLAND PRESS
• ABOUT THE SOCIETY FOR ECOLOGICAL RESTORATION INTERNATIONAL
• ABOUT THE ECOLOGICAL RESTORATION INSTITUTE AT NORTHERN ARIZONA UNIVERSITY
• Title Page
• Copyright Page
• Table of Contents
• FOREWORD
• ACKNOWLEDGMENTS
• INTRODUCTION
• PART I - The Context for Restoration
• PART II - Restoring Ecosystem Functions and Processes
• PART III - Restoring and Protecting Biological Diversity
• PART IV - Conducting Restoration: Practical Concerns
• APPENDIX 1 - Species Mentioned in Text
• APPENDIX 2 - Threatened, Endangered, and Sensitive Vertebrate Species in Arizona, New Mexico, Southern Utah, and Colorado
• APPENDIX 3 - Arizona Threatened, Endangered and Sensitive Plants Potentially Affected by Ponderosa Pine Forest Restoration
• APPENDIX 4 - Colorado Threatened, Endangered and Sensitive Plants Potentially Affected by Ponderosa Pine Forest Restoration
• APPENDIX 5 - Nevada Threatened, Endangered and Sensitive Plants Potentially Affected by Ponderosa Pine Forest Restoration
• APPENDIX 6 - New Mexico Threatened, Endangered, and Sensitive Plants Potentially Affected by Ponderosa Pine Forest Restoration
• APPENDIX 7 - Utah threatened, Endangered, and Sensitive Plants Potentially Affected by Ponderosa Pine Forest Restoration
• REFERENCES
• ABOUT THE CONTRIBUTORS
• Index
• Island Press Board of Directors