Executive Summary

Although bark beetles are native to forests of the western U.S., recent high levels of bark beetle-caused tree mortality have alarmed natural resource professionals and the public alike. Over the past decade severe drought periods in combination with unhealthy forest conditions have resulted in unprecedented levels of bark beetle-caused tree mortality across the West. Fortunately, we are positioned to address the unhealthy forest conditions contributing to bark beetle outbreaks by actively managing forests of the West. Active forest management consists of manipulating forests through various means including mechanical thinning, prescribed burning, planting, and other techniques at varying scales. Given the current expanse of western forests susceptible to beetle attack, together with compounding factors such as drought, we cannot stop large outbreaks. However, with additional resources we can minimize the impacts of ongoing and future outbreaks on the highest priority acres in the West. Without increased active forest management we can expect more bark beetle outbreaks, severe wildfire, and negative impacts on public benefits from forests. Now is the window of opportunity for action.

The Problem: Unhealthy Forests and Bark Beetle Outbreaks.

The current condition of western forests is a result of many influences, not the least of which is the past actions of humans on the landscape. Although human activity has contributed to unhealthy conditions of many western forests, current climatic conditions are combining with these forest conditions to trigger widespread bark beetlecaused tree mortality. Many of today’s western forests are denser, have different species composition and stand structure, and lack age diversity compared with forests prior to European settlement. In the wetter, high elevation forests of the West, stand density is naturally high but the majority of stands have reached an age where bark beetle susceptibility is peaking. For these reasons, bark beetles are flourishing in many western forests, negatively impacting communities, and placing important public values at risk.

The Consequences: Public Benefits at Risk.

Healthy forests provide clean air and water, wildlife habitat, recreational opportunities, and serve as renewable sources of forest products. The nation depends upon these public benefits derived from healthy forests for their economic, social, and ecological wellbeing. These public benefits are being negatively impacted by bark beetle outbreaks, and are at risk of being negatively impacted for many generations to come. Native bark beetles are important components of western forest ecosystems and some level of bark beetle-caused tree mortality is desired for proper ecosystem function. However high levels of tree mortality negatively impact public benefits from forests. From 2002 to 2003, the number of forested acres in the West detected with bark beetle-caused tree mortality saw the largest increase ever recorded, more than doubling from 4 million to 10 million acres.

A Part of the Solution: Western Bark Beetle Assessment.

This assessment consolidates the most up-to-date information on bark beetle outbreaks in the western U.S. and outlines a framework for prioritized action. This framework includes: a map of high priority acres to be considered for active forest management at the local level, a toolbox of scientifically-sound active management techniques to mitigate negative impacts from bark beetles, and the identification of cooperative groups that can leverage resources and manage bark beetle outbreaks across all boundaries. This framework will serve to efficiently and effectively address this growing problem on the highest priority acres in the West. Even with additional resources and a highly concerted effort, there will be no quick fix; this problem requires a commitment to long-term forest stewardship which can shift the balance back toward healthy, vigorous forests that are resilient to drought and bark beetle attacks. This stewardship strategy can help ensure that forests continue to provide the numerous public benefits that Americans value for generations to come.

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Western Bark Beetle Assessment March 07