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Chapter 1
MORE THAN BIG TREES
Reed F. Noss
Humans delight in superlatives. Big things, in particular, impress and inspire us: Mount Everest, the Grand Canyon, dinosaurs, whales ... redwoods. Redwoods (i.e., the coast redwood, Sequoia sempervirens) deserve all the lavish terms used to describe them. No one with an open mind could walk through an old-growth redwood forest without being humbled. No thoughtful person could stand beneath one of these immense trees, gaze up into its canopy, and help but think that here is a remarkable organismâso much more than all the board-feet of lumber that men might cleave from it. Not only are the coast redwoods among the largest living trees, they are among the largest living organisms ever to inhabit the earth. Their close ancestors have been here since other giantsâincluding the dinosaursâcame and went. An entire forest of these trees is one of the most remarkable expressions of natureâs productive capacity. And it is beautiful, truly beautiful.
A redwood forest is more than big trees. From the bewildering variety of life and past life (e.g., woody debris) on the forest floor to the intricate community of fungi, lichens, liverworts, vascular plants (including trees several meters tall), earthworms, millipedes, mollusks, insects, and salamanders tens of meters up in redwood canopies, the redwood forest is a complex ecosystem. And like virtually every ecosystem that contains something of commercial value to humans, the redwood forest has declined markedly in quality and extent over recent decades. Although the coast redwood, as a species, is in no immediate danger of extinction, the old-growth redwood forest has declined in area by more than 95 percent since European settlement (U.S. Fish and Wildlife Service 1997) and is in danger of being lost as an intact, functioning system.
Evidence is mounting that redwood forests, like many other ecosystems, cannot perpetuate themselves as small, isolated fragments in human-altered landscapes. Such fragments lose their diversity over time and may even risk losing the ability to grow new, giant trees. For example, large patches of old-growth redwoods, with their complex crown structure, capture significant quantities of water from fog. This water may be crucial to their ability to grow large under conditions of moisture stress (see chap. 2). Will redwoods of the stature we see today ever return to these impoverished landscapes? Perhaps not. Furthermore, we are learning that young stands of redwoodsâeven stands approaching two hundred years oldâlack many of the ecological attributes and habitat values of older forests. This should come as no surprise when we are dealing with a tree that can grow more than 100 m tall and 5 m thick, and whose potential life span is more than two thousand years. Redwood forests will be conserved only when we recognize them for all their values, including those values we are only beginning to understand and some that we will never fully comprehend.
The Value of Redwoods
This book, written in support of Save-the-Redwood Leagueâs master plan, is meant to provide scientific guidance for saving the redwoods by assembling available information pertinent to their conservation and management. This mission assumes that redwood forests have value. These values, already touched on above, range from the directly economic to the aesthetic, recreational, and spiritual. An increasing number of people believe that the redwood forest has intrinsic value independent of humans and that people have no right to diminish this value. We will not address subjective values to any great depth in this book, not because we think such values are unimportantâindeed they are what motivate us to pursue work in conservation biologyâbut because it is a large enough task merely to pull together the available information on more tangible, scientific topics. More important, we believe that a profound respect for redwood forests emerges from an understanding and appreciation of their fascinating natural history, and that this respect provides the most solid foundation for a conservation ethic.
The value of redwood forests can be perceived from several frames of reference. Viewing the redwood forest within a broad context is essential. One element of that context is the historic. Knowing that todayâs redwoods are relicts of an ancient lineage extending back to the age of the dinosaurs and once covering large portions of North America and other continents gives us pause to reflect on where redwoods have been and where they are going. Could this venerable lineage, which has persisted over vast spans of time while the continents drifted about and while innumerable co-occurring species arose, prospered, and then declined to extinction, be terminated before our eyes? The extinction of the coast redwood species may be unlikely any time soon, but the ecological extinction of the old-growth redwood forest is no fantasy.
As detailed in chapter 2, the brief interval over which modern humans have wrought extreme changes to the redwood forest contrasts with a much longer history, during which changes in distribution and abundance of redwood and its relatives were no less dramatic but which took place much more slowly. Although modern redwood associations, often with codominant species, such as Douglas-fir and tanoak, may or may not have had close analogs in the past, the millennial redwood forests surviving today reflect a set of environmental and biogeographic conditions from a particular time in the past. Environmental conditions have never been static over long periods, and the conditions under which todayâs old growth developed may not be replicated in the foreseeable futureâthus, the âclimaxâ redwood forests we know today may be impossible to recreate. Some ecologists might call them historical artifacts. Nevertheless, a lineage that has persisted for so long and in the face of so much global turmoil demands our admirationâand our careful stewardshipâif we want it to keep evolving into the future.
The redwood forest also can be placed within a broader context by considering its present qualities in comparison with other forest types and regions, across the continent and worldwide. Such considerations are vitally important for making conservation decisions on large scales. World Wildlife Fund (WWF) recently completed a conservation assessment of the terrestrial ecoregions of the United States and Canada (Ricketts et al. 1999), the results of which are being compared with similar assessments conducted for other continents. The redwood region stood out as a globally significant ecoregion in this assessment.
The WWF study had several goals, which included identifying ecoregions that support globally outstanding biological and ecological qualities, assessing the types and immediacy of threats to ecoregions, and identifying appropriate conservation activities for each of 116 ecoregions in the United States and Canada. Biological distinctiveness was determined through an analysis of species richness, endemism, distinctiveness of higher taxa (families, orders, etc.), unusual ecological or evolutionary phenomena, and global rarity. Conservation status was based on an assessment of habitat loss, habitat fragmentation, degree of protection, and current and potential threats. Each ecoregion was evaluated for biological distinctiveness and threat only in comparison with other ecoregions of the same major habitat (e.g., temperate coniferous forest). The Northern California Coastal Forests ecoregion (which generally corresponds to the redwood region discussed in this book; see fig. 1.1) placed in the highest class in all three assessmentsâbiological distinctiveness, conservation status and threat, and overall conservation priorityâwhen compared with other ecoregions of the same major habitat type globally.
We should bear in mind that the WWF assessment evaluated all habitats in the redwood region, and as we will see (e.g., chap. 3, 4, and 5), the redwood forest is not particularly high in species richness and endemism. The redwood region ranked high, in large part, because of the impressive (indeed, unsurpassed) biomass, structural complexity, and other unique ecological qualities of redwood forests. Associated habitats in the region, including coastal grasslands, chaparral, oak woodlands and savannas, wetlands, and diverse aquatic communities, add to the richness and distinctiveness of the region. Moreover, the redwood forests face a high level of threat to their persistence in a natural state (Ricketts et al. 1999). The high ranking by WWF suggests that land management in this globally significant and highly imperiled ecoregion should be subject to more intense scrutiny than in regions with more modest biological and ecological values.
Figure 1.1. The Redwood Region as discussed in this book (A) and as compared to the Northern California Coastal Forests Ecoregion of World Wildlife Fund (B) (Ricketts et al. 1999).
Simply put, the redwoods region has much to lose if managed unsustainably. There is ample reason to believe that management of redwood forests over the past century and a half has not been sustainableâespecially when sustainability is interpreted in the properly broad sense of sustaining all species, structures, and processes of the forest ecosystem. This dire situation necessitates three kinds of action: (1) protection of the most biologically significant remaining stands of redwoods, both old growth and second growth, representing the natural range of variation of redwood forest types and within a configuration of reserves adequate to maintain ecological integrity over time; (2) restoration of many areas of degraded redwood forest to something resembling natural conditions; and (3) truly sustainable management of appropriate redwood stands for timber and other values.
Purpose and Scope of This Book
This book is meant to provide the scientific basis for the three kinds of action just listed: protection, restoration, and sustainable management of the redwood forest. We focus largely on the redwood forest but recognize that the biological richness of the redwood region springs from the rich mosaic of terrestrial, riparian, and aquatic habitats on the landscape. We seek to give conservation organizations the information, technical tools, and broad perspective they need to evaluate redwood sites and landscapes for conservation, while providing public and private foresters and land managers with relevant information for managing redwoods and associated biological communities wisely. Through our review of the natural history and ecology of the redwood forest, we hope to acquaint readersâprofessional and amateur alikeâwith this unique ecosystem and stimulate a deep appreciation of its many values. We hope that many of you will be inspired to venture into the forest, with proper respect, to acquaint yourselves more intimately with its many microhabitats and creatures.
The chapters are organized to provide a reasonably comprehensive account of the redwood forest, including its geologic and cultural history, natural history, ecology, management, and conservation. We focus on the coast redwood species but discuss its close relatives when appropriate. Chapter 2 reviews the history of the redwood lineage, from the probable origin of the family in the Triassic period, through its diversification and subsequent decline in the Cenozoic era, to its drastic diminishing by logging in recent decades. We also review the history of redwoods conservation, addressing efforts to preserve both the Sierran redwood (giant sequoia) and the coast redwood.
Chapters 3 and 4 address the subjects of redwood trees, communities, and ecosystems. Chapter 3 focuses on the redwood vegetation and the variation in assemblages over the range of the species, as well as the vascular plants, fungi, and lichens associated with redwoods; this chapter also discusses the remarkable communities of organisms associated with redwood canopies. Chapter 4 takes a closer look at redwoodsâtheir life history, architecture, genetics, environmental relations, and disturbance regimes. In chapter 5, we address the terrestrial fauna of redwood forests, with particular attention to some of the species threatened by logging. Chapter 6, a review of the aquatic ecosystems of the redwood region, draws attention to the effects of logging and other landscape modification on aquatic fauna, especially fish and amphibians. Chapter 7 discusses conservation planning, as applied to redwood forests on a landscape scale; it includes a demonstration of a method for selecting âfocal areasâ for conservation action. Chapter 8 reviews management alternatives for redwood forests, with emphasis on silviculture but also including restoration and management of redwood parks. Chapter 9, the conclusion, summarizes the lessons of previous chapters.
We hope this book, as a whole, will serve as a model for similar projects involving other ecosystems. There are many fascinating and imperiled ecosystems worldwideâforests, savannas, grasslands, shrublands, aquatic and marine ecosystems, and others (Noss et al. 1995; Noss and Peters 1995)âdeserving book-length treatments of their own. Only when a significant number of people develop a deep understanding and appreciation of these ecosystems will we have a decent chance of saving them. There is little time to waste.
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Chapter 2
HISTORY OF REDWOOD AND REDWOOD FORESTS
John O. Sawyer, Jane Gray, G. James West,
Dale A. Thornburgh, Reed F. Noss, Joseph H. Engbeck Jr.,
Bruce G. Marcot, and Roland Raymond
The history of any taxon, community, or ecosystem provides a context for interpreting its current distribution and status. Narrowly distributed species have always interested naturalists. One pattern that begs explanation is the restriction of redwood to a relatively narrow coastal strip from central California to extreme southwestern Oregon. Sometimes a limited geographic distribution reflects a short historyâthe species has evolved only recently and, perhaps, is in the process of expanding its range. Or a restricted distribution may reflect a limitation in available habitat (e.g., species on islands or islandlike physical habitats, such as serpentine outcrops). In still other instances, the present range of a species may be but a tiny remnant of a much broader distribution in the past. This is the case for redwood and its close relatives.
This chapter reviews the history of redwood and closely related species, from their antecedents more than 100 million years ago to their restricted status today. We summarize the early development of redwood and its close relatives, through their expansion to become among the most widely distributed conifers during the Cretaceous and Tertiary periods, and through their drastic diminishment over the past few million years as mountain ranges and rain shadows formed and climates became more severe. We also review the history of human occupation and use of the redwood forest, from the first recorded settlements in the early Holocene, through the subsistence uses of the Yurok people, to the generally unsustainable logging practices that characterize the twentieth century. This long history of redwood and its associated species, both plants and animals, provides an important perspective for forest managers today (box 2.1). The chapter concludes with a ray of hopeâa summary of the redwood preservation movement and its accomplishments to date. We hope these accomplishments continue, so the long history of redwood does not come to a premature end.
Author contributions: Sawyer, general organization; Gray, pre-Holocene; West, Pleistocene-Holocene transition and Holocene; Thornburgh, logging history; Noss, section introductions, transitions, and general writing and editing; Engbeck, conservation history; Marcot, box on paleoecology; Raymond, box on Yuroks.
Box 2.1. Why Should Managers Care About Paleoecology?
The longevity of an individual redwood tree reminds us that history has shaped todayâs redwood forests. We might perceive these forests as unchanging during the brief visit afforded by a hike, a scientific study, a management plan, or even a human lifetime, but that would be illusory. Redwood forests are dynamic, changing with shifting climates, coastlines, ecological influences, and the evolution and dispersal of organisms.
Noss (1992; echoed by Grumbine 1992, 1994) described the conservation of b...
