Archaeological Study of the Settlement Gorozhane in 2018

В 2018 г. были продолжены археологические исследования поселения X-XI вв. у д. Горожане (Новосокольнический район Псковской области). Была доисследована южная половина раскопа 1 (24 кв. м). Раскоп 2 (площадь 16 кв. м) был заложен в южной части поселения у западного края площадки. Общая площадь исследований составила 40 кв. м. Под слоем распашки в раскопе 1 сохранился непотревоженный культурный слой мощностью до 0,2 м, который содержит следы крупного пожара. Предварительная датировка пожара - середина - вторая половина X в. В раскопе 2 слой перепахан до самого материка - борозды тракторной распашки прослежены на всей площади раскопа. Керамический комплекс более чем на 90% состоит из лепной керамики. Находки гончарной керамики немногочисленны. Впервые на памятнике встречены фрагменты западнославянской («балтийской») керамики. Коллекция индивидуальных находок представлена 327 предметами. Значительную часть коллекции составляют стеклянные и каменные бусы. Кроме того, среди находок представлены предметы вооружения, украшения, торговый инвентарь, бытовые предметы, несколько дирхемов. In 2018, archaeological excavations of the 10-11 centuries settlement near Gorozhane (Novosokolnichesky district, Pskov Region) were continued. The excavations of the southern half of the site 1 (24 sq. m.) was completed. In the southern part of the settlement at the western edge of the site, excavation 2 (16 sq. m.) was started. The total area of the research was 40 sq. m. Under the plowed layer in excavation 1, there has been preserved an undisturbed cultural layer thick to 0.2 m, which contains traces of a large fire. The fire is preliminary dated by the middle of the second half of the 10 century. In excavation 2, the layer was plowed to the very mainland - the furrows of tractor plowing were traced throughout the entire area of the excavation. The 90 % of the ceramic complex is stucco ceramics. Pottery items are few. For the first time, fragments of West Slavic (“Baltic”) ceramics were found on the site. The collection of individual finds is represented by 327 items. A significant part of the collection consists of glass and stone beads. Besides, the finds are represented by weapons, jewelry, trade equipment, household items, several dirhams.

Managing Fuels, Tree, and Stand Growth Using Prescribed Fire and Alternatives in Young Mixed Conifer Stands

Background In the wake of increasingly frequent and severe wildfires in California, artificial regeneration and density management facilitate prompt reforestation and the rapid growth of large, fire-resistant trees. Young plantations are particularly prone to high-severity wildfire effects, suggesting the implementation of fuel reduction treatments in the early stages of stand development. The extent to which density management (i.e., thinning) and fuels management (i.e., prescribed fire) can work together is uncertain given their potentially conflicting effects on tree and stand level growth. We investigated how four different treatments – mastication, mastication plus herbicide, two prescribed burns, and mastication plus two burns – affected individual and stand-level growth versus fuel loads in mixed-conifer plantations during young stand development in the north-central Sierra Nevada, California, USA. Results The mastication plus herbicide treatment maximized individual tree growth, especially for white fir and incense-cedar, but fuel loads doubled after five years without the use of fire. The mastication only treatment resulted in a 151% increase in fuel loads over the same period, and individual tree growth was comparable to the burn only and mastication plus burn treatments. The burn only treatment greatly decreased fuel loads but also resulted in low relative stand growth. The mastication plus burn treatment prevented fuel accumulation and generally did not slow down individual tree growth. In addition, stand growth occurred at a rate similar to that of the mastication plus herbicide treatment. Conclusions Mastication followed by repeated prescribed burning could be a viable management strategy to reduce wildfire hazard without sacrificing growth in young mixed-conifer stands that are entering a vulnerable stage of fire risk. Mastication in combination with herbicide may grow trees to a large, fire-resistant size more quickly, but does not address fuel buildup. The use of fire alone can effectively reduce fuels while not substantially impacting individual tree growth, but stand growth may decline relative to mastication and herbicide.

Large California wildfires: 2020 fires in historical context

Background California in the year 2020 experienced a record breaking number of large fires. Here, we place this and other recent years in a historical context by examining records of large fire events in the state back to 1860. Since drought is commonly associated with large fire events, we investigated the relationship of large fire events to droughts over this 160 years period. Results This study shows that extreme fire events such as seen in 2020 are not unknown historically, and what stands out as distinctly new is the increased number of large fires (defined here as > 10,000 ha) in the last couple years, most prominently in 2020. Nevertheless, there have been other periods with even greater numbers of large fires, e.g., 1929 had the second greatest number of large fires. In fact, the 1920’s decade stands out as one with many large fires. Conclusions In the last decade, there have been several years with exceptionally large fires. Earlier records show fires of similar size in the nineteenth and early twentieth century. Lengthy droughts, as measured by the Palmer Drought Severity Index (PDSI), were associated with the peaks in large fires in both the 1920s and the early twenty-first century.

Impact of a Large Fire and Subsequent Pollution Control Failure at a Coke Works on Acute Asthma Exacerbations in Nearby Adult Residents

Clairton, Pennsylvania, is home to the largest coke works facility in the United States (US). On 24 December 2018, a large fire occurred at this facility and damaged pollution control equipment. Although repairs were not completed for several months, production continued at pre-fire capacity and daily emissions increased by 24 to 35 times, with multiple exceedances of monitored levels of outdoor air pollution (OAP). The aim of this study was to objectively evaluate the impact of this industrial incident and resultant OAP exceedances on asthma morbidity. We assessed pre-fire and post-fire rate ratios (RR) of outpatient and emergency department (ED) visits for asthma exacerbations among nearby adult residents. Pre-fire versus post-fire RRs increased for both visit types: RR = 1.82 (95% CI: 1.30, 2.53; p < 0.001) and 1.84 (95% CI: 1.05, 3.22; p = 0.032) for outpatient and ED visits, respectively. Additionally, total visit rates increased on days with OAP exceedances: RR = 2.47 (95% CI: 1.52, 4.01; p < 0.0001), 1.58 (95% CI: 1.00, 2.48; p = 0.048) and 1.79 (95% CI: 1.27, 2.54; p = 0.001) for PM2.5, SO2, and H2S exceedance days, respectively. These results show a near doubling of acute visits for asthma exacerbations in nearby adult residents during this industrial incident and underscore the need for prompt remediation and public notification of OAP exceedances to prevent adverse health impacts.

Impact of a Large Fire and Subsequent Pollution Control Failure at a Coke Works on Acute Asthma Exacerbations in Nearby Adult Residents

Clairton, Pennsylvania, is home to the largest coke works facility in the United States (US). On 24 December 2018, a large fire occurred at this facility and damaged pollution control equipment. Although repairs were not completed for several months, production continued at pre-fire capacity and daily emissions increased by 24 to 35 times, with multiple exceedances of monitored levels of outdoor air pollution (OAP). The aim of this study was to objectively evaluate the impact of this industrial incident and resultant OAP exceedances on asthma morbidity. We assessed pre-fire and post-fire rate ratios (RR) of outpatient and emergency department (ED) visits for asthma exacerbations among nearby adult residents. Pre-fire versus post-fire RRs increased for both visit types: RR = 1.82 (95% CI: 1.30, 2.53; p < 0.001) and 1.84 (95% CI: 1.05, 3.22; p = 0.032) for outpatient and ED visits, respectively. Additionally, total visit rates increased on days with OAP exceedances: RR = 2.47 (95% CI: 1.52, 4.01; p < 0.0001), 1.58 (95% CI: 1.00, 2.48; p = 0.048) and 1.79 (95% CI: 1.27, 2.54; p = 0.001) for PM2.5, SO2, and H2S exceedance days, respectively. These results show a near doubling of acute visits for asthma exacerbations in nearby adult residents during this industrial incident and underscore the need for prompt remediation and public notification of OAP exceedances to prevent adverse health impacts.

Verification of Red Flag Warnings across the Northwestern U.S. as Forecasts of Large Fire Occurrence

Red Flag Warnings (RFWs) issued by the National Weather Service in the United States (U.S.) are an important early warning system for fire potential based on forecasts of critical fire weather that promote increased fire activity, including the occurrence of large fires. However, verification of RFWs as they relate to fire activity is lacking, thereby limiting means to improve forecasts as well as increase value for end users. We evaluated the efficacy of RFWs as forecasts of large fire occurrence for the Northwestern U.S.—RFWs were shown to have widespread significant skill and yielded an overall 124% relative improvement in forecasting large fire occurrences than a reference forecast. We further demonstrate that the skill of RFWs is significantly higher for lightning-ignited large fires than for human-ignited fires and for forecasts issued during periods of high fuel dryness than those issued in the absence of high fuel dryness. The results of this first verification study of RFWs related to actualized fire activity lay the groundwork for future efforts towards improving the relevance and usefulness of RFWs and other fire early warning systems to better serve the fire community and public.

Fires can overwinter in boreal forests of North America

&lt;div&gt;The boreal forest stores 35 % of the world&amp;#8217;s soil carbon reserves. Wildfires burn frequently in the boreal forest of North America and drive the boreal forest carbon balance. Previously, lightning strikes and human activities were identified as the sole ignition sources for wildfires in the boreal regions of North America. In recent years however, fire managers in Alaska, USA and Northwest Territories, Canada have started reporting the occurrence of overwintering fires. Overwintering fires are fires, that survive the cold and wet boreal winter by smouldering in deep, carbon-rich soils and re-emerge early in the subsequent spring, when fire weather favours fire spread.&lt;/div&gt;&lt;div&gt;Using the location and ignition dates of 42 overwintering fires reported by fire managers in Alaska and Northwest Territories between 2002 and 2017, we developed an algorithm to identify these new ignition sources. Our algorithm detected 8 out of 9 additional reported fires we used for validation, and further identified 15 unreported overwintering fires. Even though overwintering fires make up only 0.5 % of the burned area in total, they can amount to up to more than 10 % of the annual burned area after exceptionally large fire years.&lt;/div&gt;&lt;div&gt;We found that overwintering of fires is facilitated by deep burning into the organic soils. Overwintering fires occur more frequently after large fire years in combination with subsequent mild winters and springs leading to an early snowmelt.&lt;/div&gt;&lt;div&gt;In a warming climate, the boreal forest is burning more frequently and more intensely. As a consequence, the burned area and burn depth are predicted to increase. Our results suggest that overwintering fires are closely tied to these conditions and will therefore occur more often in the future.&lt;/div&gt;