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.

Designing a fuel-sampling program that accurately and efficiently assesses fuel load at relevant spatial scales requires knowledge of each sample method’s strengths and weaknesses. We obtained loading values for six fuel components using five fuel load sampling techniques at five locations in western Montana, USA. The techniques included fixed-area plots, planar intersect, photoloads, a photoload macroplot, and a photo series. For each of the six fuels, we compared (1) the relative differences in load values among techniques and (2) the differences in load between each method and a reference sample. Totals from each method were rated for how much they deviated from totals for the reference in each fuel category. The planar-intersect method, which used 2.50 km of transects, was rated best overall for assessing the six fuels. Bootstrapping showed that at least 1.50 km of transect were needed to obtain estimates that approximate the reference sample. A newly developed photoload method, which compared fuel conditions on the forest floor with sets of pictures calibrated for load by fuel type, compared well with the reference and planar intersect. The commonly used photo series consistently produced higher mean load estimates than any other method for total fine woody debris (0.05–0.20 kg m–2) and logs (0.50–1.25 kg m–2).

Lithofacies analysis of the Tertiary Ojo Alamo Sandstone and related strata in the San Juan Basin indicates that Laramide (Late Cretaceous-early Tertiary) volcanism and uplift north of the present-day San Juan Basin controlled sedimentation patterns of Upper Cretaceous and lower Tertiary rocks. Eight major lithofacies reflect changes in sedimentation that occurred during this time.The Ojo Alamo Sandstone is characterized in most areas of the San Juan Basin by a pebbly, trough-crossbedded lithofacies. A related channel-form sandstone and shale facies makes up the Ojo Alamo at Mesa Portales. Both lithofacies include both sediment derived from north of the present-day San Juan Basin and sediment eroded and reworked from (1) a carbonaceous shale and channel-form sandstone facies, (2) a shale and volcaniclastic sandstone facies, and (3) a volcaniclastic conglomerate and sandstone facies.The pebbly, trough-crossbedded lithofacies, which was deposited by streams on alluvial plains, differs in grain size, pebble composition, and transport direction on the east and west sides of the present-day basin. At least two distinct source areas for the streams are suggested by these differences. One source is in the area of the present-day Needle Mountains and western San Juan Mountains. A second source is located in the area of the central to eastern San Juan Mountains of southwest Colorado. Sediments deposited by alluvial streams in the western San Juan basin include sand-and pebblesize material. Initially, Ojo Alamo streams carried up to 25 percent volcanic pebbles reworked from the Animas Formation or from Upper Cretaceous andesitic flows in the source area. Later streams, however, carried an increasing percentage of quartz pebbles over volcanic pebbles.Lithofacies of the Ojo Alamo in the eastern San Juan Basin include channel sandstone and conglomerates and a channel-form sandstone and shale facies. Compared to sediments of the western alluvial complex, the eastern sediments (mapped as Ojo Alamo Sandstone, upper part of the Animas Formation, and Nacimiento Formation) are finer grained, contain few pebbles, contain less than 1 percent volcanic pebbles, and show different transport directions. Mudstone interbeds are thicker and more abundant, especially at Mesa Portales where an accompanying down-dip change in the alluvial system contributes to formation of the channel-form sandstone and shale lithofacies. 81 on July 13, 2015 specialpapers.gsapubs.org Downloaded from on July 13, 2015 specialpapers.gsapubs.org Downloaded from

This report details a procedure for identifying fuel loading models (FLMs) in the field. FLMs are a new classification system for predicting fire effects from on-site fuels. Each FLM class represents fuel beds that have similar fuel loadings and produce similar emissions and soil surface heating when burned using computer simulations. We describe how to estimate fuel load in the field, match the load estimates to an appropriate FLM, and use the FLMs to predict the smoke or soil heating that could result from burning those loads. The FLM names can also be used as fuel descriptors in other applications, including inputs into fire models for predicting fire effects, data layers for mapping fuel conditions, and supplements to vegetation data for more complete environmental descriptions to use in restoration or wildlife habitat planning.