Forest Health and Resiliency Division

Growing Healthy Forests in Washington


From helping public and private landowners care for their trees to leading the state’s efforts to reduce uncharacteristically severe wildfires, the Forest Health and Resiliency Division works to improve the health of Washington’s forests.

Growing healthy forests means using science to understand the needs of trees, bugs, fungi, fire, water, and more. The Washington State Department of Natural Resources develops information about all the types of forests that we manage—from rainforests on the Olympic Peninsula, to moderate Puget lowlands, to the pine-dominated forests of central and eastern Washington.

Our scientists carry out research and monitoring that DNR uses to make science-based decisions about its forest management practices. DNR's Forest Health and Resiliency Division works with federal and other partners to provide technical assistance about tree and forest health care to all types of public and private landowners. Whether you are interested in healthy tree growth, diseases or pests that affect trees, or in how to create older forest conditions next to streams, lakes, and rivers, DNR can assist.

2020 Statewide Forest Action Plan Update

More than 22 million acres of Washington — half of the state — is forested, effecting clean air and water and our quality of life. To help our forests thrive, Washington's Forest Action Plan provides a comprehensive review of forests across all lands — public, private, rural and urban — and offers proactive solutions to conserve, protect and enhance the trees and forests that people and wildlife depend on.

In 2008, Congress tasked each state with developing a Forest Action Plan. The first Washington State Forest Action Plan was published in 2010 and a revision was released in 2017. The updated Forest Action Plan will be submitted to the U.S. Department of Agriculture (USDA) Forest Service for review in 2020.

The Forest Action Plan lets the state receive funding from the USDA Forest Service’s state and private forestry programs. During the 2018 fiscal year, these programs provided more than $12.8 million to conserve and protect our state’s forests.

In Washington, more than 215,000 small forestland owners collectively manage 6.5 million acres of land. There are 12 million acres of private land under state fire protection, and Washington has 558 rural fire departments. These partners, among others, benefit directly from the Forest Action Plan.

The Forest Action Plan will also support other efforts at DNR, such as the state's 20-Year Forest Health Strategic Plan and the Wildland Fire Protection 10-Year Strategic Plan.

If you have questions about the Forest Action Plan, please contact Andrew Spaeth at

Sign up to receive regular updates about revisions to the Forest Action Plan here.

Forest Health Strategic Plan: Eastern Washington

Two photos showing before and after forest treatments

(Amy Hendershot/USDA Natural Resources Conservation Service photos)

Over the last several years DNR has taken an active leadership role to increase the pace and scale of forest restoration across all lands in eastern Washington to improve forest health and protect communities against catastrophic wildfires.

DNR, the Legislature, the Washington Department of Fish and Wildlife, tribes, federal agencies, forest stakeholders and others have recognized for the last 15 years that eastern Washington forests are not in a condition to be resilient and resistant to wildfires and drought-related insect outbreaks and diseases. The 2014 and 2015 wildfire seasons crystalized the risks facing these Washington forests and made clear the need for action to address forest health issues on a meaningful scale. Scientists expect the impacts from climate change to greatly exacerbate these risks. The warm and dry conditions that occurred in 2015 are projected to be the new normal by mid to late century.

In 2016, the Legislature directed DNR to develop a forest health strategic plan. DNR determined that to meet the intent of the Legislature, and to address the forest health issue in a meaningful way, it needed to adopt a guiding philosophy of “all lands, all hands.” This DNR guiding philosophy means the agency aims to address forest health issues at a landscape-scale and in coordination with all landowners to ensure forest health treatments advance in a coordinated, strategic fashion.

The 20-Year Forest Health Strategic Plan is the high-level framework guiding work and investments in central and eastern Washington to improve forest health, help forests adapt to projected climatic changes, and achieve forest-related ecological, economic, and social benefits. The overarching strategy is to maximize the effectiveness of forest health treatments by coordinating, planning, prioritizing, and implementing forest management activities across large landscapes.

To help accomplish the plan, Commissioner of Public Lands Hilary Franz signed an historic agreement in 2017 with the U.S. Forest Service to provide a new tool in the forest restoration effort, known as the Good Neighbor Authority or GNA. The GNA allows the state to partner with the Forest Service under an agreement that allows DNR to conduct forest, watershed, and rangeland restoration services on federal ground as agents of the federal government. Learn more about the GNA in Washington here.

Read more about the 20-Year Forest Health Strategic Plan here.

If you have questions about the DNR’s forest health restoration projects, please contact us at 360-902-1300 or email

Community and Landowner Assistance

Landowner receives help from a forester

Forest health specialists provide technical assistance and recommendations on tree and forest health care for state and private forest lands throughout Washington. They assist forest landowners and land managers with: identifying present or future forest insect and disease issues, as well as other adverse environmental problems such as drought, wind damage, or winter damage; pest prevention and suppression activities such as slash disposal, blowdown salvage, sanitation salvage, thinning methods, planting recommendations and pheromone and pesticide applications; pesticide use and hazard tree evaluations; providing input into the development of forest management prescriptions that reduce the risk of forest stands from insects and disease; field and classroom training for professional foresters, forest landowners and school children regarding forest insect and disease identification, issues, conditions and management techniques.

If you need assistance with any of these issues, please give us a call at 360-902-1300 or email

For those living in central and eastern Washington, DNR also provides free forester consultations to private landowners to help evaluate wildfire risk on their land. Do you know what your property's wildfire risk is? If you would like to find out, please click here. Cost share opportunities for Central and Eastern Washington may be available to non-federal owners of fewer than 5,000 acres forestland seeking to improve forest health and reduce the threats of bark beetle and wildfire damage.

Additional Resources
  • Firewise USA ®: Administered through the National Fire Protection Association, the Firewise USA ® program works with local fire districts, conservation districts, counties, and extension programs to help homeowners and communities to prepare for wildfire.
  • Forest Stewardship Program: The Forest Stewardship Program provides land management advice and assistance to forest owners. The program helps assess resource conditions and forest health, identify problems and opportunities, and identify management practices to achieve objectives.
  • Urban and Community Forestry Program: DNR's Urban and Community Forestry Program provides technical, educational and financial assistance to Washington’s cities and towns, counties, tribal governments, non-profit organizations, and educational institutions. The UCF program seeks to educate citizens and decision-makers about the economic, environmental, social and aesthetic benefits that healthy community trees provide. The program's mission is to help communities develop self-sustaining urban forestry programs that enhance the health and functionality of urban trees and forests to maximize those benefits.
  • Washington State University Extension: Washington State University Extension Forestry provides education and information about forest management to forest owners. The extension offers classes, workshops, field days, and publications. Additional forestry resources – such as coached planning sessions, publications, and videos – can be found on the WSU Extension website.

Annual Forest Health Highlights Report

The Forest Health Highlights in Washington report is published annually by DNR’s Forest Health and Resiliency Division and the USDA Forest Service each spring. It summarizes the major forest insect and disease conditions from the previous year across all ownerships throughout Washington. Much of what is reported are results of aerial surveys and ground based surveys, but it also includes information on special monitoring projects, suppression projects, and other forest-health related projects and initiatives. It also includes information on recent forest damaging weather events, droughts, and wildfires. Printed copies are available on request by contacting 360-902-1300 or

Past reports

Forest Disease Information

Up close of Dothistroma Needle Blight

(Joseph OBrien/USDA Forest Service photo)

Our trees and forests are subject to a wide variety of pests and diseases, which are usually caused by bacteria, viruses, and most commonly, fungi. Tree diseases can decay wood, decrease tree growth and cause tree mortality in both forested and urban environments. Overall, forest diseases can impact carbon sequestration, purification of water, reduction of flood risk and cultural and recreational values. Many of our diseases in Washington are native and have been here a long time, often directly influencing the biodiversity and nutrient cycling in forests. All parts of a tree, including roots, stems, branches, and foliage, can be infected by the different organisms that cause diseases, resulting in different impacts on a tree’s health. They often have specific host preferences and environmental conditions in which they live, reproduce and spread. Non-native and invasive diseases are a constant threat to our forests since our trees have no natural defenses against the pathogens. Information about specific diseases and projects we are working on can be found below.

If you have questions about tree diseases or other forest health questions, including management and treatment options, please contact our State Forest Pathologist, Dan Omdal, at 360-902-1692 or email

Forest Management Guides
Forest Insect and Disease Leaflets

Foliar Diseases

Root Diseases

Dwarf Mistletoes

Other Diseases

Additional Resources

Forest Insect Information

Douglas-fir tussock moth

(Donald Owen/California Department of Forestry and Fire Protection photo)

DNR’s forest entomologists provide technical assistance to private landowners and state land managers with identification and management of forest insect pests. The primary focus is on insects that cause mortality such as bark beetles, those that cause growth loss and stress such as defoliators, and those that affect wood quality. We emphasize integrated forest pest management methods that focus on increasing stand resistance to insect attack and resilience following any damage that may occur. Management strategies that can increase resistance and resilience include increasing vigor of leave trees through selective thinning, reducing the proportion susceptible hosts, altering stand structure and/or age classes, planting species appropriate for the site, and reducing available breeding material (slash management or salvage following storms and fires). We annually monitor populations of Douglas-fir tussock moth and western spruce budworm in eastern Washington. We assist with the annual aerial survey. When unexpected levels of damage occur, we may conduct special monitoring projects to determine levels of mortality and potential causes. We also provide assistance to state and private land managers with specific insect monitoring, stand evaluations, and suppression projects. In some stands where forest health treatments have been applied, we install long-term plots to monitor changes in insect activity.

If you have questions about forest insects in Washington, please contact our State Forest Entomologist, Glenn Kohler, at 360-902-1342 or email

Forest Management Guides
Forest Insect and Disease Leaflets

Bark Beetles


Sucking Insects

Additional Resources

Climate Change and Forest Health

Big leaf maple die off

Climate change projections suggest that Washington will continue to have increased temperatures and decreased precipitation during the growing season. This will undoubtedly contribute to tree stress, making them more susceptible to insects and diseases. Increases in tree mortality are likely to occur. The extensive droughts of 2012 and 2015 contributed to greater than expected tree mortality and damage across the state. Exceptional weather events are likely to increase in years to come, with more events similar to these. Major forest pests that are known to increase damage following droughts and extreme weather events include bark beetles, root diseases and foliar diseases. Any changes in the population dynamics of forest insects and pathogens in response to climate will be dependent on the biology and phenology (climate-influenced recurring annual events, such as budding) of the species in question, their hosts and their natural enemies – all with varying responses to environmental conditions. To make matters more complicated, changes may vary by ecoregion. Research on climate change in these complex ecosystems is challenging and still evolving, and there is no clear consensus on future outcomes. However, a few themes have emerged:

  • If climate change results in more frequent and intense droughts we can expect to see more tree mortality from insect outbreaks and root diseases due to increased tree stress. However, these pests will still require their range of suitable hosts to maintain outbreaks.
  • In a warmer climate, insects can reduce their development time. For some bark beetle species, this may shorten the length of generation time or allow them to occupy ranges farther north in latitude or at higher elevations. In recent years, mountain pine beetle has been documented killing pines outside of its historic range in northern Canada. For some defoliators, the outcome of shorter development time may be more uncertain because they rely heavily on synchrony in time with their hosts.
  • Unseasonable extremes in temperatures can effect forest insects, but in various ways. Warmer winters could lead to greater survival of some bark beetles, with the greatest effect at higher latitudes and elevations where extreme cold has excluded them in the past. Early spring warmups could influence some insects to emerge out of synchrony with their hosts or expose larval stage defoliators to late freeze events. Sustained temperatures above or below an insect’s developmental thresholds may slow activity and delay development, possibly exposing them to natural controls longer.

For landowners and land managers it is challenging to know how to adapt to coming climate changes that are uncertain. In a changing climate it is more important than ever that DNR encourage and educate landowners to improve stand resistance to forest pests and resilience to recover from damage. Stand resistance and resilience can be increased by doing activities that increase tree vigor, reduce competition, increase species diversity and retain or plant species best adapted to the site. DNR is updating its Forest Action Plan to ensure healthy forests statewide in the face of emerging challenges such as climate change. The Forest Action Plan identifies long term challenges in our forests and outlines a strategy for improving forest health, including in areas of biodiversity and habitat conservation, urban forestry, forest restoration, stewardship of working forestlands, wildfire hazard reduction, improving water quality and quantity, and Puget Sound restoration.

Learn more about DNR’s response to climate change here. If you have questions about climate change and forest health, please contact us at 360-902-1300 or email

Forest Health on State Lands

For over a decade, DNR has been actively and successfully working to restore the health and resiliency of forests on State Lands in eastern Washington. Despite these efforts, many thousands of acres of forests remain at risk from wildfire, insects and disease. In 2017, the Washington State Legislature passed a new law, Chapter 248, Laws of 2017 (E2SHB 1711), which provides DNR with new tools and increased flexibility to address the growing forest health problem. The new law clarifies DNR’s roles and obligations in addressing forest health concerns on eastern forested State Lands as part of its role within the larger context of the 20-Year Forest Health Strategic Plan. As a result, the DNR has developed a Strategy to Restore Forest Health on State Lands in Eastern Washington.

The State Lands Strategy identifies key values, goals, and objectives that will guide DNR’s forest health program to success. This strategy will help inform operational and tactical decision-making through implementation and prioritization of forest health treatments on State Lands. The goal of this strategy is to create and maintain a landscape of healthy and resilient forested State Lands that supports the trust beneficiaries, the public, and a sustainable forest products market.

Aerial Survey Information

Map showing routes of 2018 aerial forest health survey

Systematic aerial surveys are conducted to collect and report on forest insects, diseases, and other disturbances across federal, state, tribal and private lands. These surveys have been conducted annually since 1947 in the Pacific Northwest by USDA Forest Service (USFS) with the cooperation of State and private partners since 1948. Aerial surveys have proven to be an efficient and economical way to detect and monitor forest change events over large forested areas. Statewide aerial surveys are conducted each year to assess forest health in Washington State. They capture mortality and discoloration caused by insects, diseases and abiotic disturbances. This relatively low cost remote sensing method gives a coarse, landscape-level overview of forest conditions. The data collected are then used with other remote sensing and ground sampling techniques to further enhance the data accuracy of significant forest health events and changes.

Aerial Survey Data Collection Methods

The primary data collection method is known as aerial sketchmapping. Data are collected by specially trained aerial observers from the USFS and Washington Department of Natural Resources (DNR). The necessary components to make this survey happen are a high-winged aircraft that provides good visibility and can fly at relatively slow speeds between 1,000 to 2,000 feet above ground level, a safety conscious pilot, and an experienced sketchmapper who can identify forest damage observed on the ground and plot it on a map while moving in the air. Areas of forest damage are recorded as polygons using a Digital Aerial Sketchmapping System (DASM). The DASM uses a moving map display, GPS, and a touch screen to create a digital version of the data while in the aircraft. The polygons are coded with attributes such as tree species affected, number of trees (or trees per acre) affected, likely cause of damage, and severity of damage. This advanced digital sketchmapping system allows rapid summarization and near real time reporting of tree mortality and damage. This is an extremely valuable tool for forest managers and other clients who can use the data to make timely decisions and assessments. Watch this video showing how the DNR and USFS conduct an aerial survey to assess the forest health of Washington state.

For more information on the aerial survey program, please contact Glenn Kohler at 360-902-1342 or

Additional Resources
  • Access the Washington Aerial Survey GIS data (under Forest Disturbance category)
  • Find the aerial survey data for your area on a 100K quad map
  • An interactive web service for the Forest Health Aerial Survey data can be found here. This is the place where the most current Annual and Cumulative Aerial Survey data are displayed. Users can create their own PDF, JPG, and PNG maps of the field of view by clicking on the printer icon in the upper right corner. Note: The Cumulative Aerial Survey data set contains several million polygons, so to speed up the loading process, the user may want to zoom in until “15 Year Mortality Indicator 2001-2015” title on the left switches from grey to black.