Active wildfire seasons in the western U.S. warrant the evaluation of post‐fire forest management strategies. Ground‐based salvage logging is often used to recover economic loss of burned timber. In unburned forests, ground‐based logging often follows best management practices by leaving undisturbed areas near streams called stream buffers. However, the effectiveness of these buffers has not been tested in a post‐wildfire setting. This experiment tested buffer width effectiveness with a novel field‐simulated rill experiment using sediment‐laden runoff (25 g/L) released over 40 min at evenly timed flow rates (50, 100 and 150 L/min) to measure surface runoff travel length and sediment concentration under unburned and high and low soil burn severity conditions at 2‐, 10‐ and 22‐month post‐fire. High severity areas 2‐month post‐fire had rill lengths of up to 100 m. Rill length significantly decreased over time as vegetation regrowth provided ground cover. Sediment concentration and sediment dropout rate also varied significantly by soil burn severity. Sediment concentrations were 19 g/L for the highest flow 2‐month post‐fire and reduced to 6.9–14 g/L 10‐month post‐fire due to abundant vegetation recovery. The amount of sediment dropping out of the flow consistently increased over the study period with the low burn severity rate of 1.15 g L−1 m−1 approaching the unburned rate of 1.29 g L−1 m−1 by 2‐year post‐fire. These results suggest that an often‐used standard, 15 m buffer, was sufficient to contain surface runoff and reduce sediment concentration on unburned sites, however buffers on high burn severity sites need to be eight times greater (120 m) immediately after wildfire and four times greater (60 m) 1‐year post‐fire. Low burn severity areas 1‐year post‐fire may need to be only twice the width of an unburned buffer (30 m), and 2‐year post‐fire these could return to unburned widths.

As wildland fires amplify in size in many regions in the western USA, land and water managers are increasingly concerned about the deleterious effects on drinking water supplies. Consequences of severe wildfires include disturbed soils and areas of thick ash cover, which raises the concern of the risk of water contamination via ash. The persistence of ash cover and depth were monitored for up to 90 days post-fire at nearly 100 plots distributed between two wildfires in Idaho and Washington, USA. Our goal was to determine the most ‘cost’ effective, operational method of mapping post-wildfire ash cover in terms of financial, data volume, time, and processing costs. Field measurements were coupled with multi-platform satellite and aerial imagery collected during the same time span. The image types spanned the spatial resolution of 30 m to sub-meter (Landsat-8, Sentinel-2, WorldView-2, and a drone), while the spectral resolution spanned visible through SWIR (short-wave infrared) bands, and they were all collected at various time scales. We that found several common vegetation and post-fire spectral indices were correlated with ash cover (r = 0.6–0.85); however, the blue normalized difference vegetation index (BNDVI) with monthly Sentinel-2 imagery was especially well-suited for monitoring the change in ash cover during its ephemeral period. A map of the ash cover can be used to estimate the ash load, which can then be used as an input into a hydrologic model predicting ash transport and fate, helping to ultimately improve our ability to predict impacts on downstream water resources.

Large wildfires can have profound and lasting impacts not only from direct consumption of vegetation but also longer‐term effects such as persistent soil erosion. The 2002 Hayman Fire burned in one of the watersheds supplying water to the Denver metropolitan area; thus there was concern regarding hillslope erosion and sedimentation in the reservoirs. The efficacy of various treatments for reducing erosion was tested, including hand scarification on contour, agricultural straw mulch, wood mulch, burned controls and unburned reference plots. Simulated rill erosion experiments were used both immediately after the fire and again 10 years post fire. To better understand untreated recovery, the same experiments were applied to control plots in post‐fire years 1, 2, 3 and 4, and in unburned reference plots in years 4 and 10. Results indicate that control and scarified plots produced significantly greater sediment flux rates – 1.9 and 2.8 g s−1 respectively – than the straw and wood mulch treatments – 0.9 and 1.1 g s−1 – immediately after the fire. Mulch treatments reduced runoff rate, runoff velocity, and sediment concentration and flux rate. The straw mulch cover was no longer present, whereas the wood mulch was still there in year 10. Vegetation regrowth was slow and mulch treatments provided effective cover to reduce sediment right after the fire. In post‐fire year 10, there were no significant differences in sediment flux rates across treatments; it is notable, however, that the wood mulch treatment (0.09 g s−1) most closely approached the unburned condition (0.07 g s−1). The burned control plots had high sediment flux rates until post‐fire year 3, when flux rates significantly decreased and were statistically no longer higher than the unburned levels from year 4 and 10. These results will inform managers of the longer‐term post‐fire sediment delivery rates and of the ability of post‐fire emergency hillslope treatments to mitigate erosion rates. Published 2019. This article is a U.S. Government work and is in the public domain in the USA.

Continuing long and extensive wildfire seasons in the Western US emphasize the need for better understanding of wildfire impacts including post-fire management scenarios. Advancements in our understanding of post-fire hillslope erosion and watershed response such as flooding, sediment yield, and debris flows have recently received considerable attention. The potential impacts of removing dead trees, called salvage logging, has been studied, however the use of remotely sensed imagery after salvage logging to evaluate spatial patterns and recovery is novel. The 2015 North Star Fire provided an opportunity to evaluate hillslope erosion reduction using two field experiments and coincidental remotely sensed imagery over 3 years. Simulated rill experiments with four flow rates were used to quantify hillslope erosion on skidder trails with and without added logging slash compared with a burned-only control. Seven replicated hillslope silt fence plots with the same treatments were also evaluated for natural rainfall events. WorldView-2 satellite imagery was used to relate ground cover and erodible bare soil between the two experiments using multi-temporal Normalized Differenced Vegetation Index (NDVI) values. Results indicate that the skid trails produced significantly more sediment (0.70 g s(-1)) than either the slash treated skid trail (0.34 g s(-1)) or controls (0.04 g s(-1)) with the simulated rill experiment. Similarly, under natural rainfall conditions sediment yield from hillslope silt fence plots was significantly greater for the skid trail (3.42 Mg ha(-1)) than either the slash treated skid trail (0.18 Mg ha(-1)) or controls (0 Mg ha(-1)). An NDVI value of 0.32 on all plots over all years corresponded to a ground cover of about 60% which is an established threshold for erosion reduction. Significant relationships between NDVI, ground cover, and sediment values suggest that NDVI may help managers evaluate ground cover and erosion potential remotely after disturbances such as a wildfire or salvage logging.

Wildfire is a natural component of sagebrush (Artemisia spp.) steppe rangelands that induces temporal shifts in plant community physiognomy, ground surface conditions, and erosion rates. Fire alteration of the vegetation structure and ground cover in these ecosystems commonly amplifies soil losses by wind- and water-driven erosion. Much of the fire-related erosion research for sagebrush steppe has focused on either erosion by wind over gentle terrain or water-driven erosion under high-intensity rainfall on complex topography. However, many sagebrush rangelands are geographically positioned in snow-dominated uplands with complex terrain in which runoff and sediment delivery occur primarily in winter months associated with cold-season hydrology. Current understanding is limited regarding fire effects on the interaction of wind- and cold-season hydrologic-driven erosion processes for these ecosystems. In this study, we evaluated fire impacts on vegetation, ground cover, soils, and erosion across spatial scales at a snow-dominated mountainous sagebrush site over a 2-year period post-fire. Vegetation, ground cover, and soil conditions were assessed at various plot scales (8 m(2) to 3.42 ha) through standard field measures. Erosion was quantified through a network of silt fences (n = 24) spanning hillslope and side channel or swale areas, ranging from 0.003 to 3.42 ha in size. Sediment delivery at the watershed scale (129 ha) was assessed by suspended sediment samples of streamflow through a drop-box v-notch weir. Wildfire consumed nearly all above-ground live vegetation at the site and resulted in more than 60% bare ground (bare soil, ash, and rock) in the immediate post-fire period. Widespread wind-driven sediment loading of swales was observed over the first month post-fire and extensive snow drifts were formed in these swales each winter season during the study. In the first year, sediment yields from north- and south-facing aspects averaged 0.99-8.62 t ha(-1) at the short-hillslope scale (0.004 ha), 0.02-1.65 t ha(-1) at the long-hillslope scale (0.02-0.46 ha), and 0.24-0.71 t ha(-1) at the swale scale (0.65-3.42 ha), and watershed scale sediment yield was 2.47 t ha(-1). By the second year post fire, foliar cover exceeded 120% across the site, but bare ground remained more than 60%. Sediment yield in the second year was greatly reduced across short- to long-hillslope scales (0.02-0.04 t ha(-1)), but was similar to first-year measures for swale plots (0.24-0.61 t ha(-1)) and at the watershed scale (3.05 t ha(-1)). Nearly all the sediment collected across all spatial scales was delivered during runoff events associated with cold-season hydrologic processes, including rain-on-snow, rain-on-frozen soils, and snowmelt runoff. Approximately 85-99% of annual sediment collected across all silt fence plots each year was from swales. The high levels of sediment delivered across hillslope to watershed scales in this study are attributed to observed preferential loading of fine sediments into swale channels by aeolian processes in the immediate post-fire period and subsequent flushing of these sediments by runoff from cold-season hydrologic processes. Our results suggest that the interaction of aeolian and cold-season hydrologic-driven erosion processes is an important component for consideration in post-fire erosion assessment and prediction and can have profound implications for soil loss from these ecosystems. (c) 2019 John Wiley & Sons, Ltd.

Post-wildfire soil erosion can be caused by water or aeolian processes, yet most erosion research has focused on predominantly water-driven erosion. This study investigates the effectiveness of three agricultural mulches, with and without a tackifier, on aeolian sediment transport processes. A wind tunnel was used to simulate post-wildfire wind erosion at three wind speeds (6, 11 and 18 m s(-1)). Shallow trays containing soil collected after a wildfire were treated with chopped rice, wheat or chopped wheat mulch; mulch treatments were also compounded with liquid treatments, tackifier to water ratios of 1:6, 1:3 and water. The mulch treatments were generally easily moved at all wind speeds with cover reductions greater than 90% at the highest wind speed. As expected, sediment loss was greatest for the bare soil treatment, ranging from 6.5 g m(-2) at the lowest wind speed which increases to 6258 g m(-2) at the highest wind speed. Adding wheat or chopped wheat mulch significantly reduced sediment loss by an order or magnitude (698 and 298 g m(-2), respectively) at the highest wind speed. Adding chopped rice straw reduced sediment loss by a half to 3573 g m(-2) at the highest wind speed, but the effect was not significant due to mobilization of the mulch. The most effective sediment loss mitigation was achieved with liquid tackifier treatments when applied to bare soil and when compounded with various mulch treatments, particularly at the highest wind speed. These results may aid management decisions when mitigating aeolian sediment transport after wildfires. Published by Elsevier B.V.

Malignancy following solid organ transplant remains a significant threat to the survival of cardiac transplant recipients. Plasma cell dyscrasias including multiple myeloma have been encountered in this population, and medication treatments traditionally used to treat these disorders demonstrate immunomodulatory effects that may have implications on the transplanted allograft. Lenalidomide is an immunomodulatory agent that has been used to treat plasma cell disorders, including light-chain amyloidosis (AL) and multiple myeloma, and represents such a class of medications in which the risks and benefits in the solid organ transplant population remain to be fully elucidated. This report highlights a clinical practice issue where the treatment of a patient’s multiple myeloma with lenalidomide may have potentiated an episode of severe acute cellular rejection and further demonstrates the need for future investigation of the optimal treatment of plasma cell disorders including AL amyloidosis and multiple myeloma following solid organ transplantation.

Following wildfires, forest managers often consider salvage logging burned trees to recover monetary value of timber, reduce fuel loads, or to meet other objectives.. Relatively little is known about the cumulative hydrologic effects of wildfire and subsequent timber harvest using logging equipment. We used controlled rill experiments in logged and unlogged (control) forests burned at high severity in northern Montana, eastern Washington, and southern British Columbia to quantify rill overland flow and sediment production rates (fluxes) after ground-based salvage logging. We tested different types of logging equipment feller-bunchers, tracked and wheeled skidders, and wheeled forwarders as well as traffic levels and the addition of slash to skid trails as a best management practice. Rill experiments were done at each location in the first year after the fire and repeated in subsequent years. Logging was completed in the first or second post-fire year. We found that ground-based logging using heavy equipment compacted soil, reduced soil water repellency, and reduced vegetation cover. Vegetation recovery rates were slower in most logged areas than the controls. Runoff rates were higher in the skidder and forwarder plots than their respective controls in the Montana and Washington sites in the year that logging occurred, and the difference in runoff between the skidder and control plots at the British Columbia site was nearly significant (p = 0.089). Most of the significant increases in runoff in the logged plots persisted for subsequent years. The type of skidder, the addition of slash, and the amount of forwarder traffic did not significantly affect the runoff rates. Across the three sites, rill sediment fluxes were 5-1900% greater in logged plots than the controls in the year of logging, and the increases were significant for all logging treatments except the low use forwarder trails. There was no difference in the first-year sediment fluxes between the feller-buncher and tracked skidder plots, but the feller-buncher fluxes were lower than the values froth the wheeled skidder plots. Manually adding slash after logging did not affect sediment flux rates. There were no significant changes in the control sediment fluxes over time, and none of the logging equipment impacted plots produced greater sediment fluxes than the controls in the second or third year after logging. Our results indicate that salvage logging increases the risk of sedimentation regardless of equipment type and amount of traffic, and that specific best management practices are needed to mitigate the hydrologic impacts of post-fire salvage logging. (C) 2016 Elsevier B.V. All rights reserved.

After the 2009 Terrace Mountain fire near Kelowna, BC, Canada, wood shred and agricultural straw mulch effects on post-fire runoff and sediment yields were compared using three experimental techniques: rainfall simulations on 1-m2 plots, concentrated flow (rill) simulations on 9-m long plots, and sediment yields from natural rainfall on 30-m2 plots. All experimental plots were located on and along a planar hillslope burned at high severity. Experiments were conducted once a year for three consecutive years beginning in Sep 2009, except for the rainfall simulations which only were conducted the first two years. Although results varied by experiment and time since fire, both agricultural straw and wood shred mulch treatments performed similarly for reducing runoff and sediment; thus were combined into a single "treated" class for analyses. The mulch treatments were effective in reducing sediment yields as compared to the controls in all three experiments in 2009. In the rill simulation experiment, the mulch treatments significantly reduced overland flow velocity and increased the proportion of overland flow that infiltrated the soil before reaching the plot outlet. The elapsed time since the fire, which was strongly related to the increase in vegetative ground cover, was a significant factor for predicting sediment yields in the statistical models. Favorable spring rainfall in 2010 and 2011 supported rapid regrowth of vegetation, which recovered similarly on all plots regardless of treatment. The runoff and sediment yields on the treated plots were similar to those measured on the control plots a year later; we concluded that the mulch was, in effect, a surrogate for a year of recovery. Given that agricultural straw mulch is an established and effective post-fire hillslope treatment, it was important to find that wood shred mulch was similarly effective in reducing post-fire runoff and sediment yields. Thus, the choice of agricultural straw or wood shreds for a post-fire mulch treatment may be based on the performance characteristics (longevity, potential to carry invasive species seeds, cost, etc.) that best fit the needs of the site.

Mulch treatments often are used to mitigate post-fire increases in runoff and erosion rates but the comparative effectiveness of various mulches is not well established. The ability of mulch treatments to reduce sediment yields from natural rainfall and resulting overland flow was measured using hillslope plots on areas burned at high severity following four wildfires in the western United States. Wheat straw mulch, wood strand mulch, and hydromulch were evaluated along with untreated control plots on multiple fires for 4 to 7 years after burning. Needle cast from fire-killed conifer trees was evaluated in an area of moderate burn severity at one fire, and seeding with genetically native seed was tested, with and without hydromulch, at another fire. Rainfall, ground cover, and soil water repellency were measured in each treatment site at all 4 fires. Mean sediment yields on the control plots ranged from 0.3 to 7.5 Mg ha− 1 in the first post-fire year, from 0.03 to 0.6 Mg ha− 1 in the second, and from 0 to 0.4 Mg ha− 1 in the third and fourth post-fire years. Assuming a linear fit between sediment yield and rainfall intensity, storms with equivalent rainfall intensities produced nearly an order of magnitude less sediment on the control plots in the second post-fire year as compared to the first post-fire year. Large storms (at least a 2-year return period, 10-min maximum rainfall intensity) produced sediment on all fires in all years where they occurred; however, sediment yields produced by large storms that occurred in the first post-fire year were larger than the sediment yields from equivalent storms that occurred in later years at the same fire. Sediment yields decreased as ground cover increased and all the mulch treatments increased total ground cover to more than 60% immediately after application. However, the longevity of the mulches varied, so that the contribution of the treatment mulch to total ground cover varied by mulch type over time. The wood strand mulch was the most long-lived of the mulch treatments and was observed in ground cover assessments throughout the study period (4 and 7 years) at two fires. The wheat straw mulch decreased nearly twice as fast as the wood strand mulch, and no hydromulch was detected after the first post-fire year on either fire where it was tested. Mulch treatment effectiveness varied when data were analyzed separately for each fire. Wood strand mulch reduced sediment yields at both fires where it was tested, wheat straw mulch reduced sediment yields at 2 of the 4 fires where it was applied, and the hydromulch tested at 2 fires did not reduce sediment yields on either. When data were normalized and analyzed by treatment across all fires, wood strand mulch reduced sediment yields for the first four post-fire years, but wheat straw mulch and hydromulch did not significantly reduce sediment yields in any post-fire year. The greater variability in the combined data resulted in fewer statistically significant treatment effects being observed as compared to the individual fire analyses. We believe the fire-specific results provide the more accurate representation of potential post-fire mulch treatment effectiveness.

In the past decade, wildfires around the world have continued to increase in size, severity, and cost. The number of people living in wildland areas has also increased, putting public safety, homes, roads, public infrastructure, water quality, and valued natural resources at risk from wildfire and secondary fire effects. Major concerns after wildfires are the increased runoff and erosion due to loss of the protective forest floor layer, loss of water storage, and creation of water repellent soil conditions. To reduce the potential postfire erosion and flooding, various postfire mitigation treatments are commonly used on highly erodible areas. We have developed and implemented rapid response approaches to compare treatment effectiveness by monitoring sediment yield and runoff response from hillslopes and small catchments. High-intensity rainfall simulation and concentrated flow (rill) experiments are done to compare treated and untreated areas within a burned area. Small watershed impoundments and/or sediment fence barriers are established within weeks following a forest fire and are monitored for three to five years to measure runoff and sediment yields from natural rainfall. These rapid response protocols allow measurements to be made during the first postfire year when runoff and erosion are likely to be greatest with continued monitoring through the initial recovery period. Our study sites in the Western U.S. encompass a range of rainfall regimes including monsoonal rains in the southwest (Arizona and New Mexico), thunderstorms in the Colorado Front Range and Northern Rockies, and wet frontal systems in Southern California. A paired watershed study that examined the effectiveness of contour-felled log erosion barriers found that runoff, peak flows, and sediment yields were generally lower on the treated sites compared to the control sites for lower intensity storms (storms with less than a 2-yr, 10-min maximum rainfall intensity return interval I10-min); however for higher intensity storms (2-yr or greater return interval I10-min) there was no detectable treatment effect. Mulch treatments (agricultural straw, wood shreds or wood strands) appear to out-perform the barrier-type treatments in reducing erosion and can be effective even for the higher intensity events. Our research results have brought a shift in post-wildfire erosion management strategies. For example, in the 1990’s contour-felled log erosion barriers were commonly used to mitigate hillslope erosion on forested landscapes; but this treatment is seldom used today. Since 2002, mulches, especially agricultural straw, are increasingly used for post-fire hillslope stabilization.