Library of Congress Cataloging-in-Publication Data

Contents

Preface

Wildfire Fuels and Fuel Reduction

Abstract

Issues for Congress

Biomass Fuels for Wildfires

Fuel Characteristics

Moisture Content

Fuel Size

Distribution of Fuels

Fuel Quantity

Fuels and Ecosystems

Frequent Low-Intensity Surface-Fire Ecosystems

Periodic High-Intensity Crown-Fire Ecosystems

Mixed Fire Regime Ecosystems

Options for Fuel Reduction for Fire Protection

Prescribed Burning

Wildland Fire Use

Thinning

Thinning with Prescribed Burning

Other Activities

Fuel Reduction Authorities and Programs

Forest Service

Department of the Interior

Authorities to Assist Fuel Reduction on Non-Federal Lands

End Notes

Wildland Fire in Ecosystems: Fire and Nonnative Invasive Plants

Abstract

Acknowledgments

Summary

1. Fire and Nonnative Invasive Plants—Introduction

Scope of this Volume

Fire Behavior and Fire Regimes

Organization and Use of This Volume

2. Effects of Fire on Nonnative Invasive Plants and Invasibility of Wildland Ecosystems

Invasion Ecology

Ecosystem Properties and Resource Availability

Properties of Native and Nonnative Plants

Nonnative Propagule Pressure

Influence of Fire on Invasions

Influence of Fire on Resource Availability and Interactions between Plant Species

Influence of Fire Severity on Postfire Invasions

Influence of Fire Frequency on Postfire Invasions

Influence of Spatial Extent and Uniformity of Fire on Postfire Invasions

Influence of Fire Season and Plant Phenology on Postfire Invasions

Influence of Weather Patterns on Postfire Invasions

Generalizations about Fire Effects on Nonnative Invasives

Question 1. Does Fire Generally Favor Nonnatives over Natives?

Question 2. Do Invasions Increase with Increasing Fire Severity?

Question 3. Does Additional Disturbance Favor Invasions?

Question 4. Do Invasions Become Less Severe with Increasing Time after Fire?

Question 5. Do Invasions Increase with Disruption of the Presettlement Fire Regime?

Question 6. Are Postfire Invasions Less Common in High Elevation Ecosystems?

Conclusions

Variation

Changing Atmosphere and Climate

Management in a Changing World

3. Plant Invasions and Fire Regimes

Fire Behavior and Fire Regimes

Biological and Physical Factors that Affect Fire Regimes

Effects of Plant Invasions on Fuels

The Invasive Plant Fire Regime Cycle

Predicting the Effects of Plant Invasions on Fire Regimes

Herbaceous Plant Invasions

Woody Plant Invasions

Preventing or Mitigating Altered Fire Regimes

Summary Recommendations

4. Use of Fire to Manage Populations of Nonnative Invasive Plants

Introduction

Use of Fire Alone to Control Nonnative Invasive Plants

Prevention of Reproduction by Seed

Induced Mortality and Prevention or Delay of Resprouting

Burning to Favor Native Species

Fire Combined with Other Treatments

Treatments that Increase Effectiveness of Prescribed Fire

Prescribed Fire to Enhance Efficacy of Other Treatments

Altering Fire Severity, Uniformity, Extent, and Frequency to Control Nonnative Invasive Plants

Prescribed Fire Severity and Uniformity in Relation to Season

Prescribed Fire Severity and Uniformity in Relation to Fuel Beds

Extent and Uniformity of Burns

Fire Frequency

Management of a Human Process: Constraints on Use of Prescribed Fire

Conclusions

5. Fire and Nonnative Invasive Plants in the Northeast Bioregion

Introduction

Fire History in the Northeast Bioregion

Nonnative Plants in the Northeast Bioregion

Interactions of Fire and Invasive Plants in the Northeast Bioregion

Forests

Deciduous and Mixed Forests

Background

Role of Fire and Fire Exclusion in Promoting Nonnative Plant Invasions in Deciduous and Mixed Forests

Effects of Nonnative Plant Invasions on Fuel Characteristics and Fire Regimes in Deciduous and Mixed Forests

Use of Fire for Controlling Nonnative Invasives in Deciduous and Mixed Forests

Coniferous Forests

Background

Role of Fire and Fire Exclusion in Promoting Nonnative Plant Invasions in Coniferous Forests

Effects of Nonnative Plant Invasions on Fuel Characteristics and Fire Regimes in Coniferous Forests

Use of Fire to Control Nonnative Invasive Plants in Coniferous Forests

Grasslands and Early-Successional Old Fields

Background

Role of Fire and Fire Exclusion in Promoting Nonnative Invasives in Grasslands and Old Fields

Effects of Nonnative Plant Invasions on Fuel Characteristics and Fire Regimes in Grasslands and Old Fields

Use of Fire to Control Nonnative Invasive Plants in Grasslands and Old Fields

Riparian and Wetland Communities

Background

Role of Fire and Fire Exclusion in Promoting Nonnative Invasives in Riparian and Wetland Communities

Effects of Nonnative Plant Invasions on Fuel Characteristics and Fire Regimes in Riparian and Wetland Communities

Use of Fire to Control Nonnative Invasive Plants in Riparian and Wetland Communities

Emerging Issues in the Northeast Bioregion

Fuel Properties of Invaded Northeastern Plant Communities and Influences on Fire Regimes

Vulnerability of Forest Gaps to Invasion

Global Climate Change

Interactions between Nonnative Invasive Plants, Fire, and Animals

Conclusions

Resources Useful to Managers in the Northeast Bioregion

6. Fire and Nonnative Invasive Plants in the Southeast Bioregion

Introduction

Fire in the Southeast Bioregion

Fire and Invasive Plants in the Southeast Bioregion

Wet Grassland Habitat

Background

Role of Fire and Fire Exclusion in Promoting Nonnative Plant Invasions in Wet Grasslands

Effects of Plant Invasions on Fuel and Fire Regime Characteristics in Wet Grasslands

Use of Fire to Manage Invasive Plants in Wet Grasslands

Pine and Pine Savanna Habitat

Background

Role of Fire and Fire Exclusion in Promoting Nonnative Plant Invasions in Pine and Pine Savanna

Effects of Plant Invasions on Fuel and Fire Regime Characteristics in Pine and Pine Savanna

Use of Fire to Manage Invasive Plants in Pine and Pine Savanna

Oak-Hickory Woodland Habitat

Background

Role of Fire and Fire Exclusion in Promoting Nonnative Plant Invasions in Oak-Hickory Woodland

Effects of Plant Invasions on Fuel and Fire Regime Characteristics in Oak-Hickory Woodland

Use of Fire to Manage Invasive Plants in Oak-Hickory Woodland

Tropical Hardwood Forest Habitat

Background

Role of Fire and Fire Exclusion in Promoting Nonnative Plant Invasions in Tropical Hardwood Forest

Cypress Swamp Habitat

Conclusions and Summary

Role of Fire and Fire Exclusion in Promoting Nonnative Plant Invasions

Effects of Plant Invasions on Fuel and Fire Regime Characteristics

Use of Fire to Manage Invasive Plants

Additional Research Needs

Emerging Issues

7. Fire and Nonnative Invasive Plants in the Central Bioregion

Introduction

Geographic Context and Chapter Organization

Fire Regimes

The Conservation Context

Overview of Nonnative Plants that Impact or Threaten the Central Bioregion

Plant-Fire Interactions

The Mesic Tallgrass Prairie Subregion

Northern and Central Tallgrass Prairie Formation

Southern Tallgrass Prairie Formation

The Great Plains Subregion

Northern Mixedgrass Prairie Formation

Southern Mixedgrass Prairie Formation

Shortgrass Steppe Formation

Riparian Formation

Conclusions

8. Fire and Nonnative Invasive Plants in the Interior West Bioregion

Introduction

Grasslands

Desert Grasslands

Mountain Grasslands

Effects of Fire and Fire Exclusion on Nonnative Plant Invasions in Interior West Grasslands

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Interior West Grasslands

Use of Fire to Manage Invasive Plants in Interior West Grasslands

Shrublands

Sagebrush Shrublands

Desert Shrublands and Shrubsteppe

Chaparral-Mountain Shrub

Effects of Fire on Nonnative Plant Invasions in Interior West Shrublands

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Interior West Shru blands

Use of Fire to Manage Invasive Plants in Interior West Shrublands

Piñon-Juniper Woodlands

Effects of Fire on Nonnative Plant Invasions in Interior West Woodlands

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Interior West Woodlands

Use of Fire to Manage Invasive Plants in Interior West Woodlands

Open-Canopy Forest

Effects of Fire on Nonnative Plant Invasions in Interior West Open-Canopy Forest

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Interior West Open-Canopy Forest

Use of Fire to Manage Invasive Plants in Interior West Open-Canopy Forests

Closed-Canopy Forests

Effects of Fire on Nonnative Plant Invasions in Interior West Closed-Canopy Forests

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Interior West Closed-Canopy Forests

Use of Fire to Manage Invasive Plants in Interior West Closed-Canopy Forests

Riparian Communities

Effects of Fire on Nonnative Plant Invasions in Interior West Riparian Communities

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Interior West Riparian Communities

Use of Fire to Manage Invasive Plants in Interior West Riparian Communities

Conclusions

9. Fire and Nonnative Invasive Plants in the Southwest Coastal Bioregion

Introduction

Grasslands

Fire and Nonnative Invasives in Grasslands

Chaparral and Coastal Scrub

Chaparral

Coastal Scrub

Fire and Nonnative Invasives in Chaparral and Coastal Scrub

Mixed Evergreen Forests

Fire and Nonnative Invasives in Mixed Evergreen Forests

Conifer Forests

Coastal Conifer Forests

Klamath and Cascade Range Conifer Forests

Sierra Nevada Conifer Forests

Fire and Nonnative Invasives in Conifer Forests

Wetland and Riparian Communities

Fire and Nonnative Invasives in Wetland and Riparian Communities

Conclusions

10. Fire and Nonnative Invasive Plants in the Northwest Coastal Bioregion

Introduction

Coastal Douglas-fir Forests

Role of Fire in Promoting Nonnative Plant Invasions in Coastal Douglas-fir Forests

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Coastal Douglas-fir Forests

Use of Fire to Manage Invasive Plants in Coastal Douglas-fir Forests

Upper Montane Conifer Forests and Meadows

Role of Fire in Promoting Invasions of Nonnative Plant Species in Upper Montane Communities

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Upper Montane Communities

Use of Fire to Manage Invasive Plants in Upper Montane Communities

Riparian Forests

Role of Fire in Promoting Nonnative Plant Invasions in Riparian Forests

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Riparian Forests

Use of Fire to Manage Invasive Plants in Riparian Forests

Oregon Oak Woodlands and Prairies

Role of Fire in Promoting Nonnative Plant Invasions in Woodlands and Prairies

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Woodlands and Prairies

Use of Fire to Manage Invasive Plants in Woodlands and Prairies

Alaska

Coastal Hemlock-Spruce Forests

Role of Fire in Promoting Nonnative Plant Invasions in Coastal Hemlock-Spruce Forests

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Coastal Hemlock-Spruce Forests

Use of Fire to Manage Invasive Plants in Coastal Hemlock-Spruce Forests

Boreal Forests

Role of Fire in Promoting Nonnative Plant Invasions in Boreal Forests

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Boreal Forests

Use of Fire to Manage Invasive Plants in Boreal Forests

Tundra

Role of Fire in Promoting Nonnative Plant Invasions in Tundra

Effects of Nonnative Plant Invasions on Fuels and Fire Regimes in Tundra

Use of Fire to Manage Invasive Plants in Tundra

Summary of Fire-Invasive Plant Relationships in Alaska

Conclusions

11. Fire and Nonnative Invasive Plants in the Hawaiian Islands Bioregion

Introduction

Description of Dry and Mesic Grassland, Shrubland, Woodland, and Forest

Lowlands

Montane and Subalpine

Fire History and the Role of Nonnative Invasives on Fire Regimes in Dry and Mesic Ecosystems

Fire and Its Effects on Nonnative Invasives in Dry and Mesic Ecosystems

Lowland and Montane Wet Forests

Fire History and the Role of Nonnative Invasives in Wet Forest Fire Regimes

Fire and Its Effects on Nonnative Invasives in Wet Forests

Use of Fire to Control Invasive Species and Restore Native Ecosystems

Conclusions

12. Gaps in Scientific Knowledge about Fire and Nonnative Invasive Plants

Abstract

Introduction

Methods

Results

Discussion

Basic Biology

Impacts, Invasiveness, and Invasibility

Distribution and Site Information

Ecological Information

Responses to Fire, Heat, and Postfire Conditions

Field Experiments Addressing Fire Effects

Representing Information Quality in Literature Reviews: Potential for Illusions of Knowledge

Monitoring, Data Sharing, and Adaptive Management

Conclusions

13. Effects of Fuel and Vegetation Management Activities on Nonnative Invasive Plants

Introduction

High-Frequency, Low-Severity Historic Fire Regime

Mixed-Severity Historic Fire Regime

Low-Frequency, High-Severity Historic Fire Regime

Altered Fire Regime

Unaltered Fire Regime

Summary

14. Effects of Fire Suppression and Postfire Management Activities on Plant Invasions

Challenges of Identifying Postfire Plant Invasions

The Invasion Process

Effects of Fire Suppression Activities on Plant Invasions

Resource Availability

Propagule Pressure

Effects of Postfire Management Activities on Plant Invasions

Resource Availability

Summary

15. Monitoring the Effects of Fire on Nonnative Invasive Plant Species

Vegetation Monitoring

Objectives

Stratification

Controls

Random Sampling

Sample Size

Statistical Analysis

Field Techniques

Other Elements of an Effective Monitoring Program

Fire Monitoring

Fire Behavior

Fuel Loading

Fire Severity

Success and Failure in Monitoring Programs

16. Fire and Nonnative Plants— Summary and Conclusions

Nonnative Invasive Species and Wildland Fire

Management Implications

Use of Fire to Control Nonnative Invasive Species

Management Implications

Questions

References

Appendix A: Glossary

End Notes

Prepared Statement for the Record of Philip S. Aune, Retired Forester, Former Research Program Manager, Redding Silviculture Laboratory, Pacific Southwest Research Station, Redding, California, before the Subcommittee on Public Lands and Forests, Sena...

Executive Summary

Testimony

End Notes

Chapter Sources

Index