Disclaimers

Canada

The exclusion of certain manufactured products does not necessarily imply disapproval nor does the mention of

other products necessarily imply endorsement by the Canadian Forest Service. Any application of a pesticide in

Canada must be in accordance with directions printed on the label of that pesticide as prescribed under the Pest

Control Products Act of Canada. Always read the label. Any pesticide used in Canada should also be recommended by provincial authorities, who should be consulted for specific advice.

United States

This publication reports research involving pesticides. It does not contain recommendations for their use, nor does it

imply that the uses discussed here have been registered. All uses of pesticides must be registered by appropriate

State and Federal agencies before they can be recommended.

CAUTION: Pesticides can be injurious to humans, domestic animals, desirable plants, and fish or other wildlife if

they are not handled or applied properly. Use all pesticides selectively and carefully. Follow recommended practices for the disposal of surplus pesticides and pesticide containers.

Authors

Walter G. Thies is a research plant pathologist, U.S. Department of Agriculture, Forest Service, Pacific Northwest

Research Station, Forestry Sciences Laboratory, 3200 Jefferson Way, Corvallis, OR 97331; and Rona N. Sturrock is

a forestry research officer, Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, 506 West

Burnside Road, Victoria, BC V8Z 1M5.

For additional copies of this publication, please contact:

USDA Forest Service Canadian Forest Service

Natural Resources, Forest Insects and Diseases

P.O. Box 3623

Pacific Forestry Centre

506 West Burnside Road

Portland, OR 97208-3623 Victoria, BC V8Z 1M5

PNW Research Station

Publications

P.O. Box 3890

Portland, OR 97208-3890

B.C. Ministry of Forestry

Silviculture Practices Branch

Forest Health Section

2d Floor, 31 Bastion Square

Victoria BC V8W 3E7
Laminated Ro Rot in

erica

Walter G. Thies

Rona N. Sturrock

U.S. Department of Agriculture

Forest Service

Pacific Northwest Research Station

Portland, Oregon

General Technical Report

PNW-GTR-349

April 1995

Published in cooperation with:

Natural Resources Canada

Canadian Forest Service

Pacific Forestry Centre

Victoria, British Columbia
Thies, Walter G.; Sturrock, Rona N. 1995. Laminated root rot in western North America. Gen. Tech. Rep. PNWGTR-349. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station.

32 p. In cooperation with: Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre.

Laminated root rot, caused by Phellinus weirii (Murr.) Gilb., is a serious root disease affecting Douglas-fir and other

commercially important species of conifers in northwestern North America. This report gives an overview of the disease as it occurs in the Pacific Northwest in Canada and the United States. Information on recognizing crown symptoms and signs of the disease is presented. The disease cycle of laminated root rot, from initiation to intensification

and distribution within infected stands, is described. Finally, disease management strategies during stand development and at stand regeneration are discussed. Features on the nomenclature of the fungus and on its management

by silvicultural and mechanical approaches also are included. The report is intended as a general reference for a

wide audience.

Keywords: lnonotus sulphurascens, laminated root rot, Phellinus sulphurascens, Phellinus weiri, Poria weirii, root

diseases.

The information presented here has been compiled from many sources and represents both published research findings and observations of forest pathologists and resource managers in the Pacific Northwest in Canada and the

United States. Some of the management recommendations are based on research still in progress. Although much

of the information focuses on high volume coastal stands, it can be generally applied to both coastal and inland (east

of the crest of the Cascade Range) stands. This report is intended as a general reference for a wide audience including laypersons, resource managers, students, and members of the research community. Although many primary

references are listed, a complete literature review or listing of all publications on laminated root rot is beyond the

scope of this presentation.

This report updates information in earlier publications intended to provide a guide to resource managers: Hadfield

1985, Hadfield and others 1986, Morrison and others 1992, Thies 1984, and Wallis 1976. These earlier publications

are recommended as sources for additional color illustrations to augment those shown here.

ii
Table l-Susceptibility of western orth American tree species to laminated root rot

Level of susceptibility”

and species

Scientific name

Highly susceptible:

Douglas-fir

Grand fir

Mountain hemlock

Pacific silver fir

White fir

Intermediately susceptible:

California red fir

Engelmann spruce

Giant sequoia

Noble fir

Pacific yew

Sitka spruce

Subalpine fir

Western hemlock

Western larch

Tolerant:

Lodgepole pine

Sugar pine

Western white pine

Resistant:

Alaska-cedar

Incense-cedar

Ponderosa pine

Port-Orford-cedar

Redwood

Western redcedar

Immune:

Hardwoodsb-

Bigleaf maple

Mallow ninebark

Ocean-spray

Red alder

Rocky Mountain maple

Vine maple

Pseudotsuga menziesii (Mirb.) Franco

Abies grandis (Dougl. ex D. Don) Lindl.

Tsuga mertensiana (Bong.) Carr.

Abies amabilis Dougl. ex Forbes

Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.

Abies magnifica A. Murr.

Picea engelmannii Parry ex Engelm.

Sequoiadendron giganteum (Lindl.) Buchholz

Abies procera Rehd.

Taxus brevifolia Nutt.

Picea sitchensis (Bong.) Carr.

Abies lasiocarpa (Hook.) Nutt.

Tsuga heterophylla (Raf.) Sarg.

Larix occidentalis Nutt.

Pinus contorta Dougl. ex Loud.

Pinus lambertiana Dougl.

Pinus monticola Dougl. ex D. Don

Chamaecyparis nootkatensis (D. Don) Spach

Libocedrus decurrens Torr.

Pinus ponderosa Dougl. ex Laws.

Chamaecyparis lawsoniana (A. Murr.) Parl.

Sequoia sempervirens (D. Don) Endl.

Thuja plicata Donn ex D. Don

Acer macrophyllum Pursh.

Physocarpus malvaceus (Greene) Kuntze

Holodiscus discolor (Pursh) Maxim.

Alnus rubra Bong.

Acer glabrum Torr.

Acer circinatum Pursh

“Levels of susceptibility: high-readily infected and readily killed; intermediate-readily infected, usually not

killed, often develops butt decay; tolerantinfrequently infected unless growing in association with the

most susceptible species, rarely killed; and resistant-rarely infected, almost never killed.

bAll hardwoods are immune.

Sources: Adapted from Filip and Schmitt 1979, Hadfield 1985, Nelson and Sturrock 1993, Wallis 1976.

III
1 Introduction

5 Symptoms and Diagnosis

5 Appearance of Disease Centers

8 Crown Symptoms

9 External Root Appearance

11 Colonized Wood

14 Fruiting Bodies

15 Disease Cycle

15 Initiation

15 lnoculum

16 Influence of Site

16 Distribution Within a Stand

17 Disease Intensification

17 Unmanaged Stands

17 Managed Stands

17 Interaction With Bark Beetles

17 Influence of Fire

19 Disease Management

20 Strategies During Stand Development

20 Survey

20 Before Harvest

20 After Harvest

20 Precommercial Stands

20 Commercial Stands

21 Strategies at Stand Regeneration

21 lnoculum Removal

21 Stump Removal

22 Push-Falling

23 Fertilization

23 Chemical Inactivation

23 Biological Agents

24 Reforestation Choices

24 Species Manipulation

25 Resistant Douglas-fir

25 Spacing Strategy

26 Modeling

27 Synopsis

28 Acknowledgments

29 Literature Cited

24

26

26

Features

What’s In a Name

Buffer Removal

Equipment-The History

Excavator Specifications (Minimum)

Contents

iv