Theresa B. Jain

Challenges of assessing fire and burn severity using field measures, remote sensing and modelling

Comprehensive assessment of ecological change after fires have burned forests and rangelands is important if we are to understand, predict and measure fire effects. We highlight the challenges in effective assessment of fire and burn severity in the field and using both remote sensing and simulation models. We draw on diverse recent research for guidance on assessing fire effects on vegetation and soil using field methods, remote sensing and models. We suggest that instead of collapsing many diverse, complex and interacting fire effects into a single severity index, the effects of fire should be directly measured and then integrated into severity index keys specifically designed for objective severity assessment. Using soil burn severity measures as examples, we highlight best practices for selecting imagery, designing an index, determining timing and deciding what to measure, emphasising continuous variables measureable in the field and from remote sensing. We also urge the development of a severity field assessment database and research to further our understanding of causal mechanisms linking fire and burn severity to conditions before and during fires to support improved models linking fire behaviour and severity and for forecasting effects of future fires.

The efficacy of salvage logging in reducing subsequent fire severity in conifer-dominated forests of Minnesota, USA

Although primarily used to mitigate economic losses following disturbance, salvage logging has also been justified on the basis of reducing fire risk and fire severity; however, its ability to achieve these secondary objectives remains unclear. The patchiness resulting from a sequence of recent disturbances-blowdown, salvage logging, and wildfire-provided an excellent opportunity to assess the impacts of blowdown and salvage logging on wildfire severity. We used two fire-severity assessments (tree-crown and forest-floor characteristics) to compare post-wildfire conditions among three treatment combinations (Blowdown-Salvage-Fire, Blowdown-Fire, and Fire only). Our results suggest that salvage logging reduced the intensity (heat released) of the subsequent fire. However, its effect on severity (impact to the system) differed between the tree crowns and forest floor: tree-crown indices suggest that salvage logging decreased fire severity (albeit with modest statistical support), while forest-floor indices suggest that salvage logging increased fire severity. We attribute the latter finding to the greater exposure of mineral soil caused by logging operations; once exposed, soils are more likely to register the damaging effects of fire, even if fire intensity is not extreme. These results highlight the important distinction between fire intensity and severity when formulating post-disturbance management prescriptions.

A Soil Burn Severity Index for Understanding Soil-fire Relations in Tropical Forests

Abstract Methods for evaluating the impact of fires within tropical forests are needed as fires become more frequent and human populations and demands on forests increase. Short- and long-term fire effects on soils are determined by the prefire, fire, and postfire environments. We placed these components within a fire-disturbance continuum to guide our literature synthesis and develop an integrated soil burn severity index. The soil burn severity index provides a set of indicators that reflect the range of conditions present after a fire. The index consists of seven levels, an unburned level and six other levels that describe a range of postfire soil conditions. We view this index as a tool for understanding the effects of fires on the forest floor, with the realization that as new information is gained, the index may be modified as warranted.

Silviculture's Role in Managing Boreal Forests

Boreal forests, which are often undeveloped, are a major source of raw materials for many countries. They are circumpolar in extent and occupy a belt to a width of 1000 km in certain regions. Various conifer and hardwood species ranging from true firs to poplars grow in boreal forests. These species exhibit a wide range of shade tolerance and growth characteristics, and occupy different successional positions. The climate is subarctic, with short growing seasons, and the soils are shallow. Both wildfires and timber harvesting play an important role in shaping the structure and composition of boreal forests. Both uneven-aged and even-aged silvicultural systems can be used to produce commercial harvests, but systems can also be designed to meet a variety of other forest management objectives. Wildlife habitat maintenance, water production or conservation, and fire hazard reduction are only some of the objectives for which silvicultural systems can be designed. Coarse wood debris, snags, shrubs, canopy layers, and species composition are examples of forest attributes that can be managed using silvicultural systems. Systems can be designed to sustain predator habitat, yet provide a continual production of http://www.ecologyandsociety.org/vol2/iss2/art8/ (1 of 9) [10/20/2008 2:53:47 PM] Conservation Ecology: Silvicultures role in managing boreal forests wood products. Uneven-aged systems tend to favor the regeneration and development of shade-tolerant species, whereas even-aged systems tend to favor shade-intolerant species. These systems and all of their permutations can create and maintain a suite of different stand compositions and structures that can be used to meet a wide variety of management objectives.

Photographic handbook for comparing burned and unburned sites within a dry forested and grassland mosiac: a tool for communication, calibration, and monitoring post-fire effects

This photograph handbook describes characteristics and burn severity of a dry forested and grassland mosaic that burned within the last decade. We show photographs of different burned and unburned sites to help compare fire occurrence in similar stands. The handbook provides local land managers with a quick, inexpensive, and efficient way to evaluate effects of prescribed fire, wildfire, or a combination of the two, based on current conditions of unburned sites. This handbook can be used as a communication, calibration, or monitoring tool. It also contains a CD (RMRS-RP-67) that documents the vegetation and soil effects from prescribed, wild, and combined fire effects in our study.

Forest descriptions and photographs of forested areas along the breaks of the Missouri River in eastern Montana, USA

This handbook presents information and photographs obtained from forest lands along the breaks of the Missouri River in eastern Montana. Forest characteristics summarized in tables with accompanying photographs can be used to provide quick estimates of species composition and densities within similar landscape features. These estimates may be useful to foresters, wildlife biologists, range ecologists, and fire and fuel specialists. The book is organized by six physiographic positions: 1) waterways (ravines or gullies), 2) south aspects 25 percent slope angle, 4) north aspects 25 percent slope angle, and 6) ridges or benches. Within each physiographic position, sites containing three overstory densities are represented. Inventory data describes the forest floor, ground-level vegetation, tree density, average crown ratio, canopy base height, and other characteristics; two photographs (close and distant view) provide a visual image and accompany the quantitative descriptions.

One-Hundred Years of Wildfire Research: A Legacy of the Priest River, Deception Creek, and Boise Basin Experimental Forests of Idaho

The 1910 fires, which burned more than 1.3 million ha of northern Rocky Mountain forests, provided a mission and management objectives for the newly created Forest Service. By 1911, the Priest River Experimental Station (Forest-PREF) was established in northern Idaho to help meet the needs of the Forest Service. Harry T. Gisborne, whose work was centered at PREF, proved to be one, if not the most influential and far-seeing fire researcher in the history of the Forest Service. Examples of his contributions include the fire danger rating system, fuel moisture sticks, short- and long-term specialized fire-weather forecasting, and the beginnings of predicting fire behavior. After Gisborne’s death in 1949, Jack Barrows, one of Gisborne’s assistants, led the fire program and introduced high-tech approaches to fire research. Barrows was instrumental in creating the state-of-the-art Fire Sciences Laboratory in Missoula, Montana. The McSweeney–McNary Act (1928) laid the groundwork for a nationwide system of forest experiment stations and experimental forests, and in 1933 Deception Creek (DCEF) and Boise Basin Experimental Forests (BBEF) were established. DCEF was located in a productive mixed conifer forest in northern Idaho. Fire was integral to studies conducted at DCEF on harvesting, regenerating, and tending western white pine stands. Research at BBEF in southern Idaho emphasized timber production within interior ponderosa pine forests and prescribed fire was studied as a means of preparing seedbeds and minimizing grass and shrub competition to trees. Similar to other dry forests of the West, wildfires were aggressively controlled at BBEF, causing portions of it to be overrun with seedlings and saplings, which created dense forests. As such, BBEF was well suited for investigating ways of restoring ponderosa pine forests. After nearly 100 years of fire research, we still strive to effectively manage forests in the face of ever-growing threats of urbanization and unwanted wildfires. Building on the legacy of research accomplished on the Idaho experimental forests and the basic understanding of fire and its effects the early researchers developed, these forests are now more valuable than ever.