Forest Health

A healthy forest is a productive forest

Maintaining a healthy forest is an important objective for most forestland owners. In this section, we provide resources to help answer questions about forest health, such as:

• Are your trees healthy or not? How can you tell?
• What are the most common tree health problems, and why do they occur?
• How can you maintain healthy trees and prevent future problems?

For more information, please conact: Oregon State University Extension Forest Health Specialist

Check out Forest Health in Oregon: State of the State 2022 conference presentations!
Interested in previous years? State of the State 2020 conference presentations! Want more? Read this blog post for a summary of the 2020 conference, "A healthy forest is no accident."

Check out Forest Health Summary for the Pacific Northwest Region 2022 Story Map created by USDA Forest Service: Forest Health Protection, Oregon Department of Forestry,
and Washington State Department of Natural Resources. 

FOREST HEALTH BY REGION

• Columbia River Gorge

FOREST HEALTH RESOURCES

Sources Key: ODF- Oregon Department of Forestry; USFS- USDA Forest Service; OSU- Oregon State University; FIDL- Forest Insect and Disease Leaflet (USFS); WSU- Washington State University; UC- University of California; NRC- Natural Resources Canada; CSU- Colorado State University; FP- Forest Pests Website; USDA APHIS- USDA APHIS; NAPPO- North American Plant Protection Organization

General Forest Health Information

Explore these links to find general forest health information and individual publication on specific diseases and insects.

• Goheen, E.M. and E.A. Willhite. 2006. Field guide to common diseases and insect pests of Oregon and Washington conifers. R6-NR-FID-PR-01-06. Portland, OR: USDA Forest Service, Pacific Northwest Region. 327 p. Available from U.S. Government Printing Office at www.gpo.gov.
• Shaw, D.C., P.T. Oester, and G.M. Filip. 2009. Managing Insects and Diseases of Oregon Conifers. Oregon State University Extension Service, EM 8980. To purchase visit OSU Extension’s online catalog at http://extension.oregonstate.edu/catalog/ and search for publication EM8980.
• USDA Forest Service Forest Insect and Disease Leaflets
• USDA Forest Service Forest Pacific Northwest Insects and Diseases
• USDA Forest Service Forest Health Highlights in Oregon in 2022
• USDA Forest Service Forest Health Protection Mapping and Reporting
• USDA Forest Service Field Guide to Diseases and Insect Pests of Northern and Central Rocky Mountain Conifers
• Oregon Department of Forestry Website (forest health fact sheets and maps)
• Oregon State University College of Forestry. The College of Forestry has a Forestry and Natural Resources Extension Program that has several practical publications on forest health issues. You can obtain these publications in hard copy from your local OSU Extension office.
• Oregon Forest Resources Institute Learning Library
• Forest Health in the Columbia River Gorge
• Washington Department of Natural Resources Forest Health
• Tree Care (OSU Extension)
• Forest Pests of North America Website
• Identifying and Managing Christmas Tree Diseases, Pests, and Other Problems (OSU PNW659)

Tree Specific Resources

• Common Insect Pests and Diseases of Sitka Spruce on the Oregon Coast (OSU EM9105)
• Disease and Insect Pests of Pacific Madrone (OSU EC1619)
• Common Insect Pests and Diseases of Shore Pine on the Oregon Coast (OSU EM9008)
• Pruning Western White Pine: A Vital Tool for Species Restoration (OSU PNW584)
• Biology and Control of Douglas-fir Needle Midge in Christmas Trees (OSU EC1373)

Disease

General Disease Resources

• Pacific Northwest Plant Disease Management Handbook

Root Diseases

• Root Disease Resources (USFS)
• Root Diseases in Oregon and Washington Conifers (USDA Forest Service)
• Annosus Root Disease (ODF)
• Annosus Root Disease (FIDL172)
• Armillaria Root Disease (ODF)
• Armillaria Root Disease (FIDL78)
• Black Stain Root Disease (ODF)
• Black Stain Root Disease (FIDL145)
• Laminated Root Rot (ODF)
• Laminated Root Rot (FIDL159)
• Laminated Root Rot in Western North America (USFS)
• Port Orford Cedar Root Disease (see Invasive Species Tab)
• Recognizing Laminated Root Rot on Stumps (USFS)
• Sudden Oak Death (see Invasive Species Tab)
• Tomentosus Root Rot (USFS)

Rots and Decays

• Managing Tree Wounding and Stem Decay in Oregon Forests (OSU EC1519)
• Brown Crumbly Rot Management Notes (USFS)
• Brown Trunk Rot Management Notes (USFS)
• Brown Cubical Rot Management Notes (USFS)
• Ganoderma Root Rot (Pacific Northwest Extension Publication)
• Gray-Brown Saprot (USFS)
• Gray Saprot Management Notes (USFS)
• Heart Rots of Incense-Cedar (FIDL30)
• Mottled Rot Management Notes (USFS)
• Pecky Rot Management Notes (USFS)
• Red Ring Rot Management Notes (USFS)
• Red Rod of Ponderosa Pine (FIDL123)
• Rust Red Stringy Rot Caused by Indian Paint Fungus (FIDL93)
• Rust Red Stringy Rot Management Notes (USFS)
• Schweinitzii Root and Butt Rot (FIDL177)
• White Mottled Rot Management Notes (USFS)
• White Pocket Root and Butt Rot Management Notes (USFS)
• White Trunk Rot of Aspen Management Notes (USFS)
• Yellow Brown Top Rot Management Notes (USFS)

Foliage Diseases

• Brown Felt Blight Management Notes (USFS)
• Cedar Leaf Blight Management Notes (USFS)
• Diplodia Tip Blight (Pacific Northwest Extension Publication)
• Dothistroma Needle Blight of Pines (FIDL143)
• Elytroderma Disease of Ponderosa Pine (FIDL42)
• Elytroderma Needle Blight (ODF)
• Larch Needle Cast Management Notes (USFS)
• Larch Needle Cast (ODF)
• Lophodermella Needle Cast (USFS)
• Red Band Needle Blight Management Notes (USFS)
• Rhabdocline Needle Cast Management Notes (USFS)
• Swiss Needle Cast Cooperative (OSU Extension)
• Swiss Needle Cast (FIDL181)
• Swiss Needle Cast Management Notes (USFS)
• Swiss Needle Cast Fact Sheet (OSU Extension)
• Swiss Needle Cast (ODF)

Cankers

• Astropellis Canker Management Notes (USFS)
• Cankers (Forest Pathology Website)
• Cankers on Western Quaking Aspen (FIDL152)
• Hypoxylon Canker of Aspen (FIDL6)
• Phomopsis Canker of Douglas-fir Management Notes (USFS)
• Pitch Canker (UC)

Rusts

• Comandra Blister Rust Management Notes (USFS)
• Comandra Blister Rust of Hard Pines (FIDL62)
• Fir Broom Rust Management Notes (USFS)
• Incense Cedar Rust Management Notes (USFS)
• Spruce Broom Rust Management Notes (USFS)
• Spruce Cone Rust Management Notes (USFS)
• Stalactiform Rust Management Notes (USFS)
• Western Gall Rust Management Notes (USFS)
• White Pine Blister Rust (see Invasive Species Tab)

Seedling Diseases

• Damping Off Management Notes (USFS)
• Fusarium Root Rot Management Notes (USFS)
• Gray Mold Management Notes (USFS)
• Nursery Diseases of Western Conifers (FIDL157)
• Phytophthora Root Rots of Seedlings Management Notes (USFS)

Insects

General Insect Resources

• Pacific Northwest Insect Management Handbook
• Pacific Northwest Nursery Integrated Pest Management Website
• Furniss, R.L., and V.M. Carolin. 1977. Western Forest Insects. USDA Forest Service, Misc. Pub. #1339. Washington, D.C.
• Identifying Insects and Arthropods in Oregon (OSU EC1630)
• Wood, D.L., Koerber, T.W., Scharpf, R.F. and A.J. Storer. 2003. Pests of the Native California Conifers. California Natural History Guide Series No. 70. University of California Press. 233 p.

Bark Beetles

• Bark and Wood Boring Beetles of the World Website
• California Fivespined Ips (FIDL102)
• Cedar Bark Beetle Management Guide (USFS)
• Douglas-fir Beetle (FIDL5)
• Douglas-fir Beetle (ODF)
• Fir Engraver (FIDL13)
• Fir Engraver (ODF)
• Ips Bark Beetle (ODF)
• Jeffrey Pine Beetle (FIDL11)
• Mountain Pine Beetle (FIDL2)
• Mountain Pine Beetle (ODF)
• Mountain and Western Pine Beetle Animated Tree Mortality Maps (USFS)
• Pine Engraver Management Guide (USFS)
• Red Turpentine Beetle (USFS)
• Roundheaded Pine Beetle (FIDL155)
• Spruce Beetle (FIDL127)
• Western Pine Beetle (FIDL1)
• Western Pine Beetle (ODF)

Wood Borers

• Ambrosia Beetles of Western Conifers (FIDL170)
• Asian Longhorned Beetle (see Invasive Species Tab)
• Bronze Birch Borer (FIDL111)
• Bronze Birch Borer (ODF)
• Carpenter Ants (OSU)
• Citrus Longhorned Beetle (see Invasive Species Tab)
• Emerald Ash Borer (see Invasive Species Tab)
• Flatheaded Fir Borer (ODF)
• Golden Buprestid (OSU)
• Horntail- Wood Wasp (USFS)
• Pacific Powderpost Beetle (Pacific Northwest Extension Publication)
• Pacific Dampwood Termite (OSU)
• Poplar-and-Willow Borer (OSU)
• Sawyer Beetles (ODF)
• Sequoia Pitch Moth (ODF)
• Sirex Woodwasp (USFS)
• Western Cedar Borer (USDA)
• Western Larch Borer Managment Guide (USFS)
• Western Subterranean Termite (OSU)
• White-spotted Sawyer (FIDL74)
• Wood Wasps and Horntails (UC)

Defoliators

• Asian Gypsy Moth (see Invasive Species Tab)
• Brownlined Looper (NRC)
• Common Emerald (Natural Resources Canada)
• Cypress Tip Moth (OSU)
• Douglas-fir Tussock Moth (FIDL86)
• Douglas-fir Tussock Moth (ODF)
• Douglas-fir Tussock Moth Trap Catches in Oregon (USFS)
• Egira simplex (NRC)
• Elm Leaf Beetle (FP)
• Enypia griseata (NRC)
• Eupithecia unicolor (NRC)
• European Pine Shoot Moth (see Invasive Species Tab)
• Fall Webworm (ODF)
• False Hemlock Looper (USFS)
• Feralia comstocki (NRC)
• Filament Bearer (NRC)
• Forest Tent Caterpillar (FIDL9)
• Gabriola dyari (NRC)
• Gray Spruce Looper (NRC)
• Greenstriped Forest Looper (NRC)
• Gypsy Moth (see Invasive Species Tab)
• Hemlock Sawfly (FIDL31)
• Larch Casebearer (FIDL96)
• Larch Casebearer (ODF)
• Larch Sawfly (FIDL8)
• Leafmining Insects (CSU)
• Lodgepole Needleminer (USFS)
• Neodiprion mundus (FIDL179)
• Nepytia umbrosaria nigrovenaria (NRC)
• Northern Pitch Twig Moth (NRC)
• Phantom Hmelock Looper (NRC)
• Pine Butterfly (USFS)
• Pine Butterfly (ODF)
• Pine Butterfly (FIDL66)
• Pine Needle Sheathminer (FIDL65)
• Ponderosa Pine Budworm (CSU)
• Ponderosa Pine Needleminer (USFS)
• Sabulodea edwardsata (NRC)
• Saddleback Looper (NRC)
• Satin Moth (see Invasive Species Tab)
• Silver-Spotted Tiger Moth (ODF)
• Spear-Marked Black Moth (FIDL156)
• Syngrapha celsa (NRC)
• Tolype dayi (NRC)
• Western Blackheaded Budworm (USFS)
• Western Hemlock Looper (USFS)
• Western Spruce Budworm (FIDL53)
• Western Spruce Budworm (ODF)
• Management of Spruce Budworm (USFS)
• Defoliation Maps of Western Spruce Budworm (USFS)
• Western Tent Caterpillar (FIDL119)
• Western Tent Caterpillar (ODF)

Seed and Cone Insects

• Conifer Cone Pests (ODF)
• Douglas-fir Cone Midge Management Guide (USFS)
• Douglas-fir Coneworm (OSU)
• Douglas-fir Seed Chalcid Management Guide (USFS)
• Fir Coneworm (Pacific Northwest Extension Publication)
• Spruce and Larch Bud Moths (USFS)

Shoot and Twig Insects

• Conifer Weevils (ODF)
• Lodgepole and White Pine Terminal Weevil (USFS)
• Sitka Spruce Weevil (FIDL47)
• Western Pine Shoot Borer (ODF)
• White Pine Weevil (FIDL21)
• White Pine Weevil (OSU)

Sucking Insects

• Balsam Woolly Adelgid and Cooley Spruce Gall Adelgid (ODF)
• Black Pineleaf Scale (ODF)
• Black Pineleaf Scale (FIDL91)
• Boxelder Bugs (CSU)
• Hemlock Woolly Adelgid (see Invasive Species Tab)
• Pine Needle Scale (USFS)
• Spruce Aphid (ODF)

Mistletoes

• Douglas-fir Dwarf Mistletoe Fact Sheet (USFS)
• Hemlock Dwarf Mistletoe (FIDL135)
• Hemlock Dwarf Mistletoe Management (USFS)
• Larch Dwarf Mistletoe (FIDL169)
• Larch Dwarf Mistletoe Management (USFS)
• Lodgepole Pine Dwarf Mistletoe (FIDL18)
• Lodgepole Pine Dwarf Mistletoe Management (USFS)
• True Fir Dwarf Mistletoe (FIDL89)
• True Fir Dwarf Mistletoe Management (USFS)
• True Mistletoes (Hardwoods) (FIDL147)
• True Mistletoe Management (USFS)
• Western Dwarf Mistletoe Management (USFS)
• Dwarf Mistletoe of Ponderosa Pine (FIDL40)

Invasive Species

General Invasive Species

• Oregon Invasive Species Council Website
• USDA Forest Service Invasive Species Resources
• Oregon Forest Pest Detector Website and Training
• Oregon Forest Pest Detectors Field Guide (OSU EM9127)
• Invasive and Exotic Species of North America Website
• The Hidden Threat in Firewood: Invasive Forest Pests (OSU EM9137)

Diseases

• Port Orford Cedar Root Disease (FIDL131)
• Port Orford Cedar Root Rot Management Notes (USFS)
• Sudden Oak Death Management Guide (OSU EM8877)
• California Oak Mortality Task Force Website
• Sudden Oak Death Webpage (ODF)
• Sudden Oak Death (ODF)
• Sudden Oak Death Pamphlet (OSU EC1608)
• Sudden Oak Death Fact Sheet (OSU EC1607)
• Sudden Oak Death and Phytophthora ramorum: A Guide for Forest Managers, Christmas Tree Growers, and Forest Tree Nursery Operators in Oregon and Washington (OSU EM8877)
• White Pine Blister Rust (USFS)

Noxious weeds​​

• Oregon Noxious Weed List (ODF)
• Invasive Weed Identification and Management (OSU EC1563)
• PNW Weed Management Handbook

Insects​

• Asian Spongy (Gypsy) Moth Learning Resources (OSU)
• Asian Longhorned Beetle (USFS)
• Asian Longhorned Beetle (USDA APHIS)
• Citrus Longhorned Beetle (NAPPO)
• Emerald Ash Borer (USFS)
• Emerald Ash Borer (USDA APHIS)
• Emerald Ash Borer (ODF)
• Emerald Ash Borer National Website
• European Pine Shoot Moth (FIDL59)
• Goldspotted Oak Borer (UC)
• Gypsy Moth (USDA APHIS)
• Gypsy Moth (FIDL162)
• Hemlock Woolly Adegid (USFS)
• Satin Moth (Pacific Northwest Extension Publication)

Vertebrate Damage

• Black Bear Damage to Forest Trees in Northwest Oregon (ODF)
• Identifying and Managing Mountain Beaver Damage to Forest Resources (OSU EM9063)
• Meadow Voles and Pocket Gophers: Management in lawns, gardens, and croplands (OSU PNW627)

Abiotic Damage

• Abiotic Injury to Forest Trees in Oregon (OSU EC1501)
• Blowdown in Western Oregon (ODF)
• Drought Stress in Conifers (ODF)

Climate

• Climate Change and Forest Health Website
• USDA Forest Service Forest Health Protection and Global Climate Change Website
• Oregon Climate Change Research Institute