Forest Restoration in the Western U.S.

Science Center Objects

This project uses new and existing field data to assess forest restoration treatment effects across broad spatial and temporal scales. WERC's Dr. Phil van Mantgem and project partners are considering the effects of restoration treatments in terms of forest structure, forest stand development, subsequent tree mortality patterns mortality, and how climate influences the success or failure of restoration treatments. Findings from this work allow managers to better predict the outcomes of restoration activities. The management of forests is becoming ever more contentious, and it is only with these detailed data that our Department of Interior (DOI) client agencies will be able to effectively plan and manage for the future of these forests.

The USGS Ecosystem science mission area is committed to helping managers make informed decisions about natural resources that can sustain our Nation’s economic and environmental well-being. Managers and policymakers are faced with a great deal of uncertainty how their actions may impact forest resources. The information products created by this project help to reveal causes and consequences of forest management treatments over short- to long-term temporal scales and from local to continental spatial scales. This research program directly informs USGS science strategy goals by supplying managers with the information they need to make sound decisions in a rapidly changing world.

Goal: To understand and predict the effects of restoration treatments on forests of the western U.S.

Forests provide multiple ecosystem services which include: the maintenance of biodiversity, watershed hydrologic integrity, and carbon storage and sequestration. In addition to these ecosystem services, forests provide cultural, spiritual, and recreational value to societies. In recognition of these features, identifying, conserving, and protecting these resources is globally important.

WERC Redwood forest field photo
(Public domain.)

Historically, two land-use changes have had lasting effects on western forests; logging and fire suppression. For the past century, almost all fires in western U.S. forests have been actively suppressed, resulting in unforeseen changes including high fuel accumulations, high densities of small trees and increasing dominance of fire-intolerant species. As a result of these changes many forests are believed to be vulnerable to major disturbances in the form of drought, disease, and severe wildfire.

In response to these changes, managers have primarily used two tools for large-scale forest restoration; mechanical thinning and prescribed fire (often these treatments are applied to the same stand). Mechanical thinning has a long history of success in commercial and non-commercial settings and numerous studies have shown prescribed fire to reduce subsequent wildfire behavior.

Old-growth forests are expected to have generally high resistance and resilience to disturbances such as severe wildfire and drought (Fulé et al. 2012, D'Amato et al. 2013). The need for forest restoration is increasingly critical. Otherwise undisturbed forests of the western U.S. are experiencing increasing tree mortality and complete diebacks linked to drought. The removal of small trees by mechanical thinning and/or prescribed fire is expected to reduce competition among residual trees so that they are more resistant (more likely to survive) when confronted with additional stressors, such as drought.

This work uses new and existing field data to assess restoration treatment effects across broad spatial and temporal scales. This project considers the effects of restoration treatments in terms of forest structure, forest stand development, subsequent tree mortality patterns mortality, and how climate influences the success or failure of restoration treatments. These findings allow managers to better predict the outcomes restoration activities.