Abstract. Changes in vegetation and fuels were evaluated from measurements taken before and after fuel reduction treatments (prescribed fire, mechanical treatments, and the combination of the two) at 12 Fire and Fire Surrogate (FFS) sites located in forests with a surface fire regime across the conterminous United States. To test the relative effectiveness of fuel reduction treatments and their effect on ecological parameters we used an informationtheoretic approach on a suite of 12 variables representing the overstory (basal area and live tree, sapling, and snag density), the understory (seedling density, shrub cover, and native and alien herbaceous species richness), and the most relevant fuel parameters for wildfire damage (height to live crown, total fuel bed mass, forest floor mass, and woody fuel mass).In the short term (one year after treatment), mechanical treatments were more effective at reducing overstory tree density and basal area and at increasing quadratic mean tree diameter. Prescribed fire treatments were more effective at creating snags, killing seedlings, elevating height to live crown, and reducing surface woody fuels. Overall, the response to fuel reduction treatments of the ecological variables presented in this paper was generally maximized by the combined mechanical plus burning treatment. If the management goal is to quickly produce stands with fewer and larger diameter trees, less surface fuel mass, and greater herbaceous species richness, the combined treatment gave the most desirable results. However, because mechanical plus burning treatments also favored alien species invasion at some sites, monitoring and control need to be part of the prescription when using this treatment.

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The 12-site National Fire and Fire Surrogate study (FFS) was a multivariate experiment that evaluated ecological consequences of alternative fuel-reduction treatments in seasonally dry forests of the US. Each site was a replicated experiment with a common design that compared an un-manipulated control, prescribed fire, mechanical and mechanical + fire treatments. Variables within the vegetation, fuelbed, forest floor and soil, bark beetles, tree diseases and wildlife were measured in 10-ha stands, and ecological response was compared among treatments at the site level, and across sites, to better understand the influence of differential site conditions. For most sites, treated stands were predicted to be more resilient to wildfire if it occurred shortly after treatment, but for most ecological variables, short-term response to treatments was subtle and transient. Strong site-specificity was observed in the response of most ecosystem variables, suggesting that practitioners employ adaptive management at the local scale. Because ecosystem components were tightly linked, adaptive management would need to include monitoring of a carefully chosen set of key variables. Mechanical treatments did not serve as surrogates for fire for most variables, suggesting that fire be maintained whenever possible. Restoration to pre-settlement conditions will require repeated treatments over time, with eastern forests requiring more frequent applications.

A variety of techniques that estimate temperature and/or heat output during fires are available. We assessed the predictive ability of metal and tile pyrometers, calorimeters of different sizes, and fuel consumption to time-temperature metrics derived from thick and thin thermocouples at 140 points distributed over 9 management-scale burns in a longleaf pine forest in the southeastern US. While all of these devices underestimate maximum flame temperatures, we found several to be usehl for characterizing other rnetrics of fire behavior. While the degree to which thermocouples underestimated maximum temperatures was based on thickness, metrics derived from thermocouple data that inte~ated time and temperature minimized this discrepancy between thin and thick thermocouples. Thermocouples also provided the most detailed spatial and temporal data of the devices tested. Pyrometers underestimated maximum temperatures relative to tl~ermocouples, but due to their low cost, can be useful for examining spatial variation in temperature during fires. Use of calorimeters is disadvantageous given their lack of precision and high labor cost. Simple fire behavior observations taken during burns and indicators of fire severity observed post-burn were inexpensive to estimate and revealed useful differences among fires. Due to the wide variation among these techniques in cost, labor, accuracy, and level of detail of results, their suitability for a particular project will vary according to research objectives and available resources. Researchers should ensure that the fire behavior parameter measured has a logical relationship to the effect of interest, is measured at an appropriate level of detail, and is reported with attention to the limitations of the measuring devices used. Estimating flame temperature and duration has become increasingly common in studies of the ecological effects of fire. Researchers have found estimates of fire temperatures and their durations correlate well with fire effects on specific plant parts (seeds, roots, cambium) or soil components (e.g., Auld and O'Conner 1991; Dichnson and Johnson 2001). Time-temperature curves are most commonly measured using thermocouples deployed with data loggers. However due to the high cost of data loggers, researchers often rely on less expensive tools such as pyrometers or calorimeters to provide an index of flame temperature or heat release. Pyrometers, namely pellets, paints, or crayons manufactured to melt or change colors at specific temperatures, are commonly used to estimate fire temperatures in ecological studies (Fonteyn et al. 1984;Hobbs et al. 1984;Gibson et al. 1990;Cole et al. 1992; Franklin et al. 1997 (Beaufait 1966; Knight 1981;Moreno and Oechel 1989;Perez and Moreno 1998).This suite of techniques commonly used by fire ecologists vary considerably in cost, level of detail of results, and most importantly, accuracy. Notably, few of these instruments measure actual flame temperatures (or heat release in the case of calorimeters) as is sometimes er...