Ecology of Wildfire Residuals in Boreal Forests (eBook)

Ajith Perera, Lisa Buse (Autoren)

eBook Download: EPUB

2014 | 1. Auflage
272 Seiten
Wiley-Blackwell (Verlag)
9781118870587 (ISBN)

Infos

This book will draw attention to the residuals in pan-boreal forest fires and synthesize the state of knowledge.  It will do so by:  (a) Examining the concept of fire residuals from different perspectives,  (b) Reviewing the growing body of scientific literature on the topic,  (c) Conceptualizing the process of residual formation in relation to scale of fire disturbance, (d) Discussing the roles of fire residuals in ecological processes, (e) Describing approaches and methods of studying fire residuals, (f) Compiling and summarizing what is known about fire residual vegetation with respect to their extent, spatial patterns, and temporal changes,  (g) Discussing how the knowledge of fire residuals is applied in forest management, including social perspective, and (h) Synthesizing the state of knowledge, identifying its uncertainties and gaps, and proposing research hypotheses.   The authors use pan-boreal scientific literature on boreal fire residuals as well as fire behaviour, fire ecology, habitat ecology, and geochemical processes.  For readers this book will be a reference for knowledge to date and a meta-analysis of research trends during the past few decades.  In addition, the authors judiciously include views constructed from their observations and research experience, from boreal Canada, when they synthesize and conceptualize the knowledge.  They also incorporate information extracted from their discussions and interactions with North American and European ecologists, forest managers, and conservationists to provide insight to different views and perspectives on the fire residuals of the boreal forest system.  This book will inform researchers and students who study boreal forest ecology, as well as policymakers and forest managers who apply forest ecological knowledge in forest management.

This book provides a review and coalescence of the current knowledge of boreal forest fire residuals, which at present is sporadic and has not been unified or synthesized.  Moreover, these are presently viewed myopically and parochially, rather than holistically.  The intent of the synthesis is to identify knowledge uncertainties and gaps and propose topics for future research. Most importantly, it brings together fire behaviour, ecological scale, vegetation ecology, and conservation biology to conceptualize forest fire residuals.  Although focused on boreal forests, the contents and principles presented are also be pertinent to other large-scale fire driven forest systems, such as dry montane forests in North America and Australian eucalypt forests. This book will add to the current knowledge base by providing a source of significant literature to-date, an in-depth examination of baseline concepts of forest fire residuals, as well as questions and research ideas to address the identified gaps. The timing is ideal because the knowledge base is beginning to expand and the interest in the topic is increasing: such a synthesis would provide an important foundation for future advances in this very relevant topical area. The book is a compact, yet comprehensive, dissertation of remnant vegetation in boreal forest fires with respect to their formation, role in ecological processes, applied importance, and a synthesis of state-of-the-knowledge and future research directions. The scope is boreal forests worldwide, including North America, Europe, and Asia. Brief TOC: Why the interest in boreal fire residuals; what are fire residuals; how are fire residuals formed; what are the ecological roles of the fire residuals; what is the role of residuals in forest management applications; synthesis, knowledge, uncertainties and research needs.

Ajith H. Perera is a senior research scientist and leads the Forest Landscape Ecology Program at the Ontario Forest Research Institute in Ontario, Canada. He has over twenty-five years of research experience in landscape ecology, much of it focused on understanding patterns and processes of boreal forest fire regimes. He has
authored many scientific publications, including several books.

Lisa J. Buse is a forest biologist who specializes in knowledge transfer at the Ontario Forest Research Institute. She has over twenty years of experience in communicating forestry sciences to practitioners, especially on forest landscape ecology including wildfire disturbances in boreal Ontario. She has also published many scientific publications and co-edited three books.

Inhalt

Acknowledgments xi

About the companion website xiii

1 Introduction 1

The boreal forest biome 2

Geographical distribution 4

Distinguishing features 6

Boreal wildfires 9

Major characteristics 9

Ecological significance 11

Goals and scope of the book 12

References 14

2 Formation of wildfire residuals 18

Factors that affect the formation of residuals 19

Boreal forest communities 20

Boreal wildfires 31

Residual formation and distribution 40

Spatial heterogeneity in fire behavior 41

Process of residual formation 44

Summary 59

References 61

3 Types of wildfire residuals and their extent 65

Types of wildfire residuals 66

A post-wildfire scene 66

Past descriptions of wildfire residuals 71

Abundance and extent of wildfire residuals 79

Snag residuals 80

Live tree residuals 81

Residual patches 84

Changes in residuals after wildfires 88

Snag residuals 88

Live tree residuals 89

Residual patches 92

Toward improved definitions and assessment 93

Reasons for improvement 93

Definitions of wildfire residuals 95

Improved study approaches 103

Summary 107

References 113

4 Ecological roles of wildfire residuals 119

Ecological processes involving snag residuals 121

Invasion by beetles 121

Colonization by woodpeckers 132

Occupation by other bird species 140

Forest regeneration 142

Roles of the residual patches 148

Providing temporary shelter 149

Supplementing the recovery 151

Creating heterogeneity 161

Ecological significance 161

Wildfire residuals and the carbon cycle 162

Wildfire residuals and nutrient and hydrological cycles 165

Summary 168

References 173

5 Role of wildfire residuals in forest management
applications 184

Restoring wildfire residuals 185

Ecological expectations 186

Considerations for application 187

Challenges and uncertainties 190

Emulating wildfire disturbance 191

Background 191

Emulating wildfire residuals by forest harvest 193

Expectations and uncertainties 197

Salvage logging 202

Background 202

Ecological consequences 204

Practical considerations 212

Uncertainties 217

Summary 220

References 222

6 Ecology of boreal wildfire residuals - a summary and
synthesis 227

Wildfire residuals and their occurrence 227

Residual vegetation types 228

Spatial patterns of residuals 231

Ecological roles of wildfire residuals 235

Snag residuals 235

Residual patches 236

A conceptual view 237

Knowledge uncertainties 239

Management applications and wildfire residuals 240

Salvage logging 240

Emulating wildfire disturbances 240

Restoring wildfire residuals 242

Suppressing fire 243

Research needs on wildfire residuals 243

Advancing research methods 243

Expanding research topics 244

Conclusion 245

Index 247

Textauszug

Chapter 2
Formation of wildfire residuals

Factors that affect the formation of residuals

1. Boreal forest communities
2. Boreal wildfires

Residual formation and distribution

1. Spatial heterogeneity in fire behavior
2. Process of residual formation

Summary

References

What factors may explain the occurrence of post-fire residual vegetation in boreal forests? That is the question we explore in this chapter in the context of boreal forest communities and boreal wildfires. Even though the boreal biome includes a wide range of geographical and climatic conditions across three continents, some commonalities exist in the pan-global boreal forest communities, terrain, ecological processes, and major natural disturbances (Shugart et al. 1992). For example, as we described in Chapter 1, wildfires burn a large total area annually throughout this biome, and the frequency of wildfire occurrence is high. Furthermore, boreal wildfires can be intense, their individual spatial signatures can be large, and they almost always contain residual vegetation. Our focus here is the formation of those wildfire residuals. We explore the many types of residual vegetation, their extent, and their spatial distribution in the next chapter.

Any discussion of the formation of wildfire residuals in boreal forest landscapes must involve three topics: the forest communities that sustain the wildfires by providing fuel, and that eventually constitute the wildfire residuals; the wildfire behavior and the thermal energy generated during the fire, which causes mortality of some or all of the vegetation; and finally, the spatial patterns of the wildfire residuals.

To address these topics, we have organized this chapter to answer two major questions: what factors affect the formation of wildfire residuals, and how are those residuals formed and spatially distributed during wildfires? Our treatment of boreal forest communities and wildfire processes will provide only an introduction to these topics, and is therefore not exhaustive or authoritative. Indeed, such an exercise is beyond the scope of this book. To learn more, we recommend several excellent texts that provide a more comprehensive discussion of the topic of boreal vegetation (e.g., Larsen 1980, Scott 1995) and boreal wildfires (e.g., Wein and MacLean 1983, Johnson 1992, Goldammer and Furyaev 1996). Also, we caution that much variability exists across the boreal regions in the specific details of both vegetation and fire events. Our attempt here may therefore appear to be an oversimplification and generalization. We hope that readers will understand that, rather than trying to account for all possible exceptions, we have instead tried to find generalities that are valid across the boreal region.

Factors that affect the formation of residuals

To understand how wildfire residuals form, familiarity with the types of boreal forest community and the behavior of wildfires is required. The former provides insights into the characteristics of the combustible material that will sustain a wildfire and the characteristics of the potential residuals. The latter provides insights into how the residuals form and how they are spatially distributed within a wildfire footprint—the spatial boundary that encompasses all fire processes. By addressing only boreal forest communities and wildfire behavior, we do not neglect the importance of climate, weather, and the geo-environment (e.g., geology, topography, soil moisture regime) in forming residuals. For example, they may change fire behavior or modify the factors that determine the composition of the residuals (Figure 2.1). Indeed, we address climate and geo-environmental variables when we discuss residual formation and the factors that influence this process.

Figure 2.1 An abstract depiction of the major factors that affect the formation of residuals in boreal wildfires. These factors operate at different ecological scales. For example, long-term climate and the local geo-environment produce changes in the types of forest communities, whereas short-term local weather and the local geo-environmental conditions directly affect the behavior of a given fire.

Boreal forest communities

Boreal forests are characterized by relatively few tree species that dominate the vegetation. These species belong to eight genera that are common throughout the range of boreal forests around the world: the conifers spruce (Picea), fir (Abies), pine (Pinus), and larch (Larix) and the hardwoods poplar (Populus), birch (Betula), alder (Alnus), and willow (Salix). The dominant species in each genus change from region to region, but a given species typically has a broad geographical range within its continent. Larsen (1980) summarized their distribution based on longitude (Table 2.1).

Table 2.1 Major tree species in the world's boreal forests and their longitudinal limits (adapted from Larsen 1980).

Genus

Continent (range of longitudes)

North America (55–160°W)

Northern Europe (5–40°E)

Western Siberia (40–120°E)

Eastern Siberia (120–170°W)

Conifers

Picea (spruce)

glauca mariana

abies (syn. excelsa)

obovata

obovata jezoensis

Abies (fir)

balsamea

sibirica

nephrolepis

lasiocarpa

sachalinensis

Pinus (pine)

banksiana

sylvestris

sylvestris

sylvestris

contorta

sibirica

pumila

cembra

Larix (larch)

laricina

sibirica sukaczewii

gmelinii (syn. dahurica)

Hardwoods

Populus (poplar)

tremuloides balsamifera

tremula

tremula

tremula suaveolens

Betula (birch)

papyrifera

pubescens

pubescens

ermanii

kenaica

pendula (syn. verrucosa) kusmisscheffii

pendula (syn. verrucosa)

platyphylla

Alnus (alder)

incana (ssp. tenuifolia)

incana

viridis (ssp. crispa, ssp. rugosa)

viridis (ssp. crispa)

viridis (ssp. fruticosa)

viridis (ssp. fruticosa)

Salix (willow)

Salix spp.

Salix spp.

Salix spp.

Salix spp.

Within these broad geographic distribution patterns, the regional distribution of tree species and their associated vegetation communities change in response to variations in geology, local climate, and topography, as has been documented for North America (e.g., Larsen 1980, Scott 1995), Fennoscandia (e.g., Esseen et al. 1997), and Siberia (e.g., Wein and MacLean 1983). One main factor that determines the local occurrence of tree species appears to be soil moisture (Table 2.2), and the direct effects of other factors, such as soil nutrient content, may be less evident (Larsen 1980). Both Wein and MacLean (1983) and Esseen et al. (1997) noted that in boreal forests in general, pines dominate the drier sites, and spruces and firs dominate the moister sites.

Table 2.2 Association of the major coniferous species with soil moisture regimes across the major boreal forest regions (summarized from Larsen 1980, Wein and MacLean 1983, and Esseen et al. 1997).

Soil moisture regime

Region

Western North America

Eastern North America

Northern Europe

Western Siberia

Eastern Siberia

Dry

Pinus contorta

Pinus banksiana

Pinus sylvestris

Pinus cembra

Moist

Picea mariana Picea glauca

Picea mariana Picea glauca Abies balsamea

Picea abies

Picea abies

Picea obovata

Wet

Picea mariana

Larix laricina Picea mariana

Picea abies Larix spp.

Picea obovata Larix sibirica Abies sibirica Larix...

Produkt-Details

• Erscheint lt. Verlag: 21.7.2014
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Biologie ► Botanik
• Themenwelt: Naturwissenschaften ► Biologie ► Ökologie / Naturschutz
• Themenwelt: Naturwissenschaften ► Geowissenschaften ► Geografie / Kartografie
• Themenwelt: Technik
• Schlagworte: Agriculture • Ökologie / Pflanzen • Angewandte Ökologie • Angewandte Ökologie • Applied Ecology • Biome • Biowissenschaften • Boreal • boreal wildfires • Ecological • fires • focus • Forest • forestry • Forstwirtschaft • Globally • importance • important • Integral • intense • intense wildfires • known • Landwirtschaft • Life Sciences • Managers • Ökologie / Pflanzen • Patterns • phenomenon academics • plant ecology • policymakers • remnants • Strategies • Study
• ISBN-13: 9781118870587 / 9781118870587