This is a print on demand edition of a hard to find publication. This report synthesizes the literature and current state of knowledge pertaining to re-introducing fire in stands where it has been excluded for long periods and the impact of these introductory fires on overstory tree injury and mortality. Only forested ecosystems in the United States that are adapted to survive frequent fire are included. Treatment options that minimize large-diameter and old tree injury and mortality in areas with deep duff and methods to manage and reduce duff accumulations are discussed. Pertinent background information on tree physiology, properties of duff, and historical versus current disturbance regimes are also discussed. Charts and tables.

Prescribed burning is an important tool throughout Southern forests, grasslands, and croplands. The need to control fire became evident to allow forests to regenerate. This manual is intended to help resource managers to plan and execute prescribed burns in Southern forests and grasslands. A new appreciation and interest has developed in recent years for using prescribed fire in grasslands, especially hardwood forests, and on steep mountain slopes. Proper planning and execution of prescribed fires are necessary to reduce detrimental effects, such as the impacts on air and downstream water quality. Check out these related products: Trees at Work: Economic Accounting for Forest Ecosystem Services in the U.S. South can be found here: https://bookstore.gpo.gov/products/trees-work-economic-accounting-forest-ecosystem-services-us-south Soil Survey Manual 2017 is available here: https://bookstore.gpo.gov/products/soil-survey-manual-march-2017 Quantifying the Role of the National Forest System Lands in Providing Surface Drinking Water Supply for the Southern United States is available here: https://bookstore.gpo.gov/products/quantifying-role-national-forest-system-lands-providing-surface-drinking-water-supply Fire Management Today print subscription is available here: https://bookstore.gpo.gov/products/fire-management-today Wildland Fire in Ecosystems: Fire and Nonnative Invasive Plants can be found here: https://bookstore.gpo.gov/products/wildland-fire-ecosystems-fire-and-nonnative-invasive-plants

Historically, many forested ecosystems in the United States burned frequently, both from lightning ignited fires and from Native American burning. Frequent fire maintained low fuel loadings and shaped forests composed of tree species adapted to survive low-intensity frequent fire. In the early 1900s, the United States government initiated a program to suppress all fires, both natural and anthropogenic. Many unintended consequences have resulted from over a century of fire suppression, such as increased tree densities and fuel, increased stress on older trees from competition, and greater risk of bark beetle attacks. These consequences are especially apparent in forests that historically burned frequently and have thus missed many fire cycles. Maintaining old trees and perpetuating large-diameter trees is an increasing concern. Stands of old trees that were historically common across vast landscapes in the United States are now relatively rare on the landscape because of harvesting (Noss and others 1995). Though logging is no longer the principal threat to most old-growth forests, they now face other risks (Vosick and others 2007). Prescribed fire has become a major tool for restoring fire-dependent ecosystem health and sustainability throughout the United States and use will likely increase in the future. However, increased mortality of large-diameter and old trees following fire has been reported in many areas around the country, and there is increased concern about maintaining these on the landscape (Kolb and others 2007; Varner and others 2005). As early as 1960, Ferguson and others (1960) reported high longleaf pine mortality after a low-intensity prescribed burn consumed the majority of heavy duff accumulations around the base of the trees. Mortality of pre-settlement ponderosa pines in prescribed burn areas in Grand Canyon National Park was higher than in control plots (Kaufmann and Covington 2001). After beginning a forest restoration program that reintroduced fire by prescribed burning at Crater Lake National Park, excessive post-fire mortality of larger ponderosa pine was observed in the burn areas, and early season burns had an even higher mortality than late season burns (Swezy and Agee 1991). Both Swezy and Agee (1991) and McHugh and Kolb (2003) reported a U-shaped mortality distribution for ponderosa pine following wildfires, with smaller- and larger-diameter trees having higher mortality than mid-diameter trees. Forest managers around the country have expressed concerns about large-diameter and old tree mortality when prescribed burning in long-unburned forests. The synthesis herein suggests recommendations for maintaining and perpetuating old trees in fire-dependent ecosystems. It expands on efforts funded by the Joint Fire Science Program (JFSP) to define the issues surrounding burning in fire excluded forests of the United States that are adapted to survive frequent fire. When the JFSP initially funded this synthesis, two JFSP projects were examining the effect of raking on reducing old ponderosa and Jeffrey pine (subsequently published in Fowler and others 2010; Hood and others 2007a). Another JFSP project examined the effect of prescribed burning under different duff moisture conditions on long-unburned old longleaf pine mortality (Varner and others 2007). Two other syntheses were also recently published on this subject: Perpetuating old ponderosa pine (Kolb and others 2007) and The conservation and restoration of old growth in frequent-fire forests of the American West (Egan 2007). The scope of the synthesis herein focuses only on limiting over story tree mortality in species adapted to survive frequent fire; therefore, the implications of fire suppression and fuel treatments on other ecosystem components are not discussed.