Fire Episodes Research Articles

Characterization of air quality and fine particulate matter sources in the town of Hinton, Alberta

With concern in recent years about dust issues and fine particulate matter (PM2.5) levels approaching a new Canadian Ambient Air Quality Standards (CAAQS), an investigation of air quality characteristics and potential sources influencing PM2.5 concentrations was undertaken in the community of Hinton, Alberta. The study was conducted for the period November 2013 to February 2016 using hourly concentrations of criteria air pollutants. Comparatively higher concentrations of PM2.5 were observed in summer (mean: 12.5 μg/m3, median: 8.0 μg/m3) than in winter (mean: 7.5 μg/m3, median: 6.0 μg/m3).The 3-year averages of annual average PM2.5 concentrations (8.1–8.9 μg/m3) were below the 2015 annual CAAQS value of 10 μg/m3. Exceedances of a 1 h Alberta Ambient Air Quality objective (58 times > 80 μg/m3) and a 24 h CAAQS (16 times > 28 μg/m3) were observed at Hinton for the study period and occurred during summer months primarily due to occurrence of forest fire episodes. A multivariate model positive matrix factorization (PMF) revealed five sources. Background dust and secondary aerosol was identified as the largest source contributing 68% to PM2.5 mass. Other sources included traffic (13.4%), an O3-rich source (12.7%), industry (3.1%) and a mixed source (3.1%). These findings offer preliminary information about contributions of different sources to PM2.5 at Hinton; and this information can support policy makers in developing appropriate management initiatives for reducing dust and secondary particulate matter pollution.

Effects of traditional extractive management on the seedling recruitment dynamics of Comanthera elegantula (Eriocaulaceae) in Espinhaço mountain range, SE Brazil

The intense harvesting of inflorescences prior to seed setting and the persistent use of fire to boost flowering are considered to be the main factors driving starflower species to extinction along the Espinhaço mountain range, in eastern Brazil. In this study we experimentally reproduced these traditional management practices upon a natural population of the starflower Comanthera elegantula (Ruhland) L.R. Parra & Giul. (Eriocaulacece) using eight distinct treatments consisting of ‘fire', “harvest” and the combined absence of these interventions over two years, in order to assess their effects on seedling recruitment. The study was conducted at the central Espinhaço range region, in Minas Gerais State, Brazil. Our results show that the extractive management practices interfere with the recruitment dynamics of C. elegantula, with fire significantly reducing the competing herbaceous cover and stimulating seedling recruitment. An intermittent fire regime seem to favor seedling establishment and growth, while sequential fire episodes seem to negatively impact the progression of seedling cohorts and the regrowth of the herbaceous cover. Additional seed input took place at local scale, probably through dispersion from outer sources and/or from seed banks. Seed pool depletion isto be expected under a persistent and efficient inflorescence collection regime and may ultimately contribute to population senescence.

From pristine forests to high‐altitude pastures: an ecological approach to prehistoric human impact on vegetation and landscapes in the western Italian Alps

Summary This paper addresses the origin and development of the oldest prehistoric pasture in the timberline ecotone known so far in the Alps and its relation to anthropogenic pressure and natural climate change. Palaeoecological and geochemical techniques were applied on the Crotte Basse mire stratigraphy (2365 m a.s.l, northwestern Italy) to describe changes in vegetation composition, forest biomass, land use and fertilization between c. 6400–1800 cal years bp. Subalpine forests dominated by Pinus cembra occurred at very high‐altitude up to c. 5600 cal years bp, when a sharp contraction of woody vegetation took place. This major vegetation shift is matched by increasing charcoal input and markers of pastoral/grazing activities (pollen, dung spores and forms of phosphorus) in the sediment sequence in this small basin. Major phases of landscape change detected in our multiproxy record chronologically match intervals of cumulative probability density of 14C ages from nearby archaeological sites, suggesting that human activity was the factor leading to massive landscape change from the onset of the Copper Age (c. 5600 cal years bp). The change may have been reinforced by climate variability in the period 5700–5300 cal years bp. Sensitivity of woody species to fires was statistically explored (Appendix S1, Supporting Information), revealing negative reactions of P. cembra and Betula to frequent fire episodes and positive reactions of Alnus viridis and Juniperus. Fire episodes do not affect Larix dynamics. Synthesis. Mt. Fallère provides some of the oldest and consistent evidence so far available in the Alps for major anthropogenic pressure at the upper forest limit. As far back as 5600 cal years bp, high‐elevation forest ecosystems were permanently disrupted and the alpine pastures were created. Palaeoecological data enable a clear distinction between a random and sporadic use of the alpine space, typical for Mesolithic and Neolithic societies, and an organized seasonal exploitation of natural resources, starting from the Copper Age onwards. The chronological comparison of independent climate proxies, palaeoecological information and pollen‐based temperature reconstructions sheds light on the relationships between climate and humans since prehistoric times.

Estimating Ambient Ozone Effect of Kansas Rangeland Burning with Receptor Modeling and Regression Analysis

Prescribed rangeland burning in April is a long-standing practice in the Flint Hills region of eastern Kansas to maintain the tallgrass prairie ecosystem. The smoke plumes originating from these fires increases ambient PM2.5 concentrations and potentially contributes to ozone (O3) exceedances in downwind communities. Source apportionment research using Unmix modeling has been utilized to estimate contributions of Kansas rangeland burning to ambient PM2.5 concentrations. The objective of this study was to investigate the potential correlations between O3 and various sources of PM2.5 that are derived from receptor modeling, and then to specifically estimate contributions of Kansas rangeland burning to ambient O3 concentrations through regression analysis. Various daily meteorological data were used as predictor variables. Multiple regression models were developed for the eight-hour daily maximum O3 as well as the daily contributions of the five PM2.5 source categories that were derived from receptor modeling. Cross correlation was analyzed among residuals of the meteorological regression models for O3 and the daily contributions of the five PM2.5 source categories in order to identify the potential hidden correlation between O3 and PM2.5. The model including effects of meteorological variables and episodic contributions from fire and industrial emissions can explain up to 78% of O3 variability. For non-rainy days in April, the daily average contribution from prescribed rangeland burning to O3 was 1.8 ppb. On 3% of the days in April, prescribed rangeland burning contributed over 12.7 ppb to O3; and on 7% of the days in April, burning contributed more than 7.2 ppb to O3. When the intensive burning activities occur in days with high O3 background due to high solar radiation or O3 carryover from the previous day, the contributions from these episodic fire emissions could result in O3 exceedances of the National Ambient Air Quality Standards (NAAQS). The regression models developed in this study demonstrated that the most valuable predictors for O3 in the Flint Hills region include the O3 level on the previous day, total solar radiation, difference between daily maximum and minimum air temperature, and levels of episodic fire and industrial emissions. The long term goal is to establish an online O3 forecasting tool that can assist regulators and land managers in smoke management during the burning season so that the intensive burning activities can be planned to avoid forecasted high O3 days and thus prevent O3 exceedance.

LOST IN CONTAGION? BUILDING A LIQUIDATION INDEX FROM COVARIANCE DYNAMICS

We propose a tool for monitoring fire sales and fund liquidations in financial markets. This liquidation index detects fire sales episodes in a contemporaneous manner and estimates their magnitude, using only publicly available data (asset prices and volumes). At every date [Formula: see text], it takes as input the movement of asset prices and realized covariances between dates [Formula: see text] and [Formula: see text] and the market depth of each asset and estimates a theoretical magnitude for fire sales over the period [Formula: see text] that generated such joint movement of prices and covariances. As such, the liquidation index spikes during fire sales episodes and can hence be used in a systemic risk management perspective, as it enables to detect fire sales episodes — even complex liquidation events such as the hedge fund crash of August 2007 which was undetected by commonly-used monitoring tools. It can also be useful in a trading and portfolio allocation perspective as it allows to distinguish between periods of “fundamental” asset behavior from fire sales periods, characterized by crowding and contagion effects and during which diversification effects are reduced.

Evaluating the representation of aerosol optical properties using an online coupled model over the Iberian Peninsula

Abstract. The effects of atmospheric aerosol particles on the Earth's climate mainly depend on their optical, microphysical and chemical properties, which modify the Earth's radiative budget. The aerosol radiative effects can be divided into direct and semi-direct effects, produced by the aerosol–radiation interactions (ARIs), and indirect effects, produced by aerosol–cloud interactions (ACIs). In this sense the objective of this work is to assess whether the inclusion of aerosol radiative feedbacks in the online coupled WRF-Chem model improves the modelling outputs over the Iberian Peninsula (IP) and surrounding water areas. For this purpose, the methodology is based on the evaluation of modelled aerosol optical properties under different simulation scenarios. The evaluated data come from two WRF-Chem simulations for the IP differing in the inclusion/no-inclusion of ARIs and ACIs (RF/NRF simulations). The case studies cover two episodes with different aerosol types over the IP in 2010, namely a Saharan dust outbreak and a forest fire episode. The evaluation uses observational data from AERONET (Aerosol Robotic Network) stations and MODIS (Moderate Resolution Imaging Spectroradiometer) sensor, including aerosol optical depth (AOD) and Ångström exponent (AE). Experimental data of aerosol vertical distribution from the EARLINET (European Aerosol Research Lidar Network) Granada station are used for checking the models. The results indicate that for the spatial distribution the best-represented variable is AOD and the largest improvements when including the aerosol radiative feedbacks are found for the vertical distribution. In the case of the dust outbreak, a slight improvement (worsening) is produced over the areas with medium (high/low) levels of AOD(−9 % / +12 % of improvement) when including the aerosol radiative feedbacks. For the wildfire episode, improvements of AOD representation (up to 11 %) over areas further away from emission sources are estimated, which compensates for the computational effort of including aerosol feedbacks in the simulations. No clear improvement is observed for the AE representation, the variability of which is largely underpredicted by both simulations.

Interpreting Temporal Changes of Atmospheric CO2Over Fire Affected Regions Based on GOSAT Observations

The carbon dioxide (CO2) emissions released from biomass burning significantly affect the temporal variations of atmospheric CO2 concentrations. Based on a long-term (July 2009–June 2015) retrieved data sets by the greenhouse gases observing satellite (GOSAT), the seasonal cycle and interannual variations of column-averaged volume mixing ratios of atmospheric carbon dioxide (XCO2) in four fire affected continental regions were analyzed. The results showed that Northern Africa (NA) had the largest seasonal variations after removing its regional trend of XCO2 with peak-to-peak amplitude of 6.2 ppm within the year, higher than central South America (CSA) (2.4 ppm), Southern Africa (SA) (3.8 ppm), and Australia (1.7 ppm). The detrended regional XCO2 ( $\triangle $ XCO2) was found to be positively correlated with the fire CO2 emissions during the fire activity period but with different seasonal variabilities. NA recorded the largest change of seasonal variations of $\triangle $ XCO2 with a total of 12.8 ppm during fire seasons, higher than CSA, SA, and Australia with 5.4, 6.7, and 2.2 ppm, respectively. During the fire episode, the positive $\triangle $ XCO2 was noticed during June–November in CSA, December to next June in NA, and May–November in SA. The Pearson correlation coefficients between the variations of $\triangle $ XCO2 and fire CO2 emissions achieved the best correlations in SA ( $R = 0.77$ and $p ). This letter revealed that fire CO2 emissions and GOSAT XCO2 presented consistent seasonal variations.

Late Holocene fire–climate relationships of the western San Juan Mountains, Colorado

In recent decades, warming temperatures and severe drought have contributed to large and severe wildfires in the south-western United States. To put current wildfires in a long-term context, we reconstructed fire events with alluvial stratigraphy methods in south-western Colorado, and compared with paleoclimate records over the late Holocene. The chronology of 32 fire-related sedimentation events from six tributary basins was established using 48 radiocarbon dates. Based on deposit characteristics, we found episodes of increased high-severity fire for 2750–2350 cal yr BP (800–400 BCE); 1400–1175 cal yr BP (550–775 CE); 1050–700 cal yr BP (900–1250 CE); and 525–250 cal yr BP (1425–1700 CE). There were peaks in low-severity fires in 2350–2000 cal yr BP (400–50 BCE) and 300–70 cal yr BP (1650–1880 CE). Two of the four episodes of high-severity fire corresponded with multi-decadal droughts, including clusters of extreme drought years. The most recent fire episode was preceded by wetter conditions and decreased frequency of extreme drought years, which facilitated the build-up of fuel loads. However, previous high-severity episodes were not consistently preceded by wetter conditions. Steep slopes and overall rugged terrain were also likely contributing factors to fuel accumulation and high-severity fires. A recent wildfire followed a fire-free interval of greater than 120 years and likely contained more extensive areas of high-severity burned area than fire events over the late Holocene.

STATUS OF PEATLAND FIRE RESEARCH IN INDONESIA

Peatland fire research has been on the increasing trend since 1997/1998 when fire episode experienced by Indonesia and ASEAN region. Its impact on transboundary haze pollution has not merely related to environmental but on social and political issues. Since then, research on peatland fire has been on local and global concerns. International scientific journals on peatland fire in the period of 1997-2014 were reviewed and analysed descriptively. The study shows that in the earlier stage, researches covered peatland fire characteristics, fire behaviour, fire causes and fire impacts on peat and biodiversity in limited area. Research concerns had been broadened to ecological, economical, social aspects, and even political aspects. Greater impacts on transboundary haze pollution had attracted scientists to study on haze-air pollution relationship with special concern on health and economical aspects. Moreover, peatland fire and climate change issues including greenhouse gas (GHG) emission had been covered and become an iconic topic of peatland fire studies. Geographycally, almost all peatland fire studies focused in Sumatera and Kalimantan. In the last two decades period, peatland fire researches had been explored and developed to spatial analyses on fire prone areas mapping, modelling on fire occurence prediction, haze trajectory, hotspot accuracy as fire indicator, and the latest issue was burned area estimation in relation to predict GHG emission. Key words: peatland fire, transboundary haze, hotspot, climate change, emission

The historical demise of Pinus nigra forests in the Northern Iberian Plateau (south‐western Europe)

Summary Pinus nigra Arn. forests dominated over extensive areas of the Northern Iberian Plateau (Spain) during the Holocene, but a strong decline during the historical period (c. 1300–700 cal. bp) led to the present fragmented populations. This demise has been generally attributed to land‐use changes or climate, but the specific roles of disturbance regimes such as fire variability and grazing on the long‐term are not fully understood yet. We combine multi‐proxy palaeoecological data (fossil pollen, spores, conifer stomata, microscopic and macroscopic charcoal) together with quantitative analyses (ordination and peak detection) from a high‐resolution sedimentary sequence (Tubilla del Lago, 900 m a.s.l.) to assess the causes of pine forests demise. A new microscopic charcoal record from an additional sequence (Espinosa de Cerrato, 885 m a.s.l.) is used to assess burning and pine decline at a more regional (100‐km radius) scale. Pinus nigra forests could cope with drought and fire regime variability (FRI = 110–500 years), with forest recovery taking c. 100–200 years after fires. Only at 1300–1200 cal. bp a long‐lasting irrecoverable demise of P. nigra forests occurred when human‐induced fires together with arable and pastoral farming became widespread in the area. Subsequently, Quercus woodlands expanded in the remnant patchy pinewoods. This vegetation shift was primarily caused by three particularly important fire episodes in less than a century (c. 1300–1200 cal. bp). Synthesis. Pinus nigra forests have shown a millennial resilience to the natural fire regime of the Northern Iberian Plateau that was characterized by relatively frequent small‐moderate fires and rare high‐intensity fires. However, frequent human‐caused crown fires and the onset of intensive farming caused their demise over an extensive area. Ongoing land‐use abandonment in the Iberian mountains could promote the occurrence of high‐intensity, severe fires due to the rapid build‐up of high fuel loads. Forest management could mimic the natural fire regime by periodically reducing fuel loads for a transitional period until natural disturbance variability is fully restored, thus preserving these relict native plant communities.

The 2015 Borneo fires: What have we learned from the 1997 and 2006 El Niños?

Fire activity in Indonesia is strongly linked with El Niño events, whose sea surface temperature (SST) patterns can weaken the Walker circulation to induce drought conditions in the region. Here we show via case analyses and idealized climate model simulations that it is the central location of the SST anomalies associated with El Niño, rather than its strength, that is mostly linked with the fire occurrence. During our study period of 1997–2015, Eastern Pacific (EP) El Niño events produced the largest fire events in southern Borneo (i.e., in 1997, 2006, and 2015), while Central Pacific (CP) El Niño events consistently produced minor fire events. The EP El Niño is found to be more capable than the CP El Niño of weakening the Walker circulation that acts to prolong Borneo’s drought condition from September to October. The extended dry conditions in October potentially increase the occurrence of fires during EP El Niño years. The 2015 fire event owes its occurrence to the location of the 2015 El Niño but not necessarily its ‘Godzilla’ strength in affecting the fire episodes over southern Borneo. Projecting the location of El Niño events might be more important than projecting their strength for fire management in southern Borneo.

Human Effects in Holocene Fire Dynamics of Central Western Patagonia (~44° S, Chile)

The forest-steppe ecotone of the eastern slope of the Andes in Central Western Patagonia (43°40'-49°15' S, Chile, South America) provides a unique area for assessing long and short term dynamics between humans and past environments. Central Western Patagonian was a demographically marginal zone inhabited intermittently and with low intensity by hunter-gatherers during the Holocene. This paper adopts a novel approach in order to assess the relationship between trends in the archaeological, pollen and charcoal records. The recognition of temporal and spatial scales in both archaeology and paleoecology is crucial for defining roles in paleofire records. The main goal of the paper is to assess the role of climate and human beings as potential ignitors of wildfires by acknowledging the scales in which they operate and the different roles either one played in paleofire trends. We investigated a case study in the Cisnes River Valley where the frequencies and magnitudes of fire episodes – reconstructed from macro-charcoal particles from the Lake Shaman intermoraine sequence – can be attributed to human action, while acknowledging the driving role of climate over broader time scales. The Lake Shaman charcoal record spanning the last 19000 cal years is compared to the archaeological record starting at 11500 cal years BP. After comparing paleofires, reconstructed from the charcoal record, with peaks and troughs in the radiocarbon record and archaeological evidence at local and site scales, we argue that this approach provides insights for assessing the timing and magnitude of human effects on the environment. We examine collation and correlation scenarios for comparative trends between the archaeological, pollen and charcoal records. The correlation of occupational events at the El Chueco 1 archaeological site and other sites along the Cisnes River Valley with the results obtained at Lake Shaman is suggestive of a combination of human agency and climate drivers in the occurrence of fires during most of the Holocene.

EFFECTS OF FIRE ON POPULATION DYNAMICS OF AN ENDEMIC HIGH ALTITUDE RUPICOLOUS GEOPHYTE

Stevia camporum (Asteraceae) is a threatened and endemic geophyte of the rocky outcrop vegetation in the high altitude grasslands on the top of the Itatiaia massif. This is a locally abundant plant, which establishes itself preferentially on vegetation mats dominated by pioneer species such as mosses (Campylopus pilifer) and by the vascular endemic plants Fernseea itatiaiae and Barbacenia gounelleana. With a very distinctive morphology, these nurse plants may differently influence the dynamics of S. camporum. These relations were previously studied for two years when a 3-day unnatural fire burned the grassy vegetation around the rocky outcrops, thereby affecting indirectly the vegetation mats (islands) growing at the exposed rocky surfaces, through ash emissions and changes on the availability of nutrients. We described pre-fire (1999-2001) and post-fire (2002-2003) population demography and growth of S. camporum under the hypothesis that Stevia demography would change due to effects of fire, such as nutrient income and, further, that responses would vary according to the dominant pioneer species of each vegetation mat. Forty-three islands containing S. camporum (total area of 30.08m2) were monitored. Despite considerable variation in rainfall between years, population structure and dynamics of S. camporum were very similar in the two pre-fire growing seasons. A massive increase in the frequency of branches in the first size class followed fire, but with nearly no changes in the other classes with a thinning process being observed. The height, number of nodes and number of fruits of Stevia camporum’s ramets showed significant differences when comparing the values for periods before and after the fire. Stevia’s demography on Fernseea (Bromeliaceae) mats was significantly different in relation to the other mat species, after fire. In Itatiaia, indirect effects of smoke produced by fire episodes seem to trigger rapid responses on rupicolous communities followed by rapid return to previous conditions, particularly in secondary species. Prolonged effects on more often disturbed communities remain to be seen, and might be relevant to community structure of high altitude outcrop vegetation.

Rapidly evolving ultrafine and fine mode biomass smoke physical properties: Comparing laboratory and field results

AbstractCombining field and laboratory results, we present biomass smoke physical properties. We report sub‐0.56 µm diameter (Dp) particle sizing (fast mobility particle sizer, FMPS) plus light absorption and scattering at 870 nm (photoacoustic extinctiometer). For Dp < 200 nm, the FMPS characterized sizing within ±20% compared to standards. As compared to the traditional scanning mobility particle sizer, the FMPS responded most accurately to single‐mode polydispersions with mean Dp < 200 nm, which characterized the smoke sampled here. Smoke was measured from laboratory fresh emissions (seconds to hours old), the High Park Fire (hours to < 1 day), and from regional biomass burning (several days). During a High Park Fire episode, light extinction rapidly reached a maximum of σep = 569 ± 21 Mm−1 (10 min) with aerosol single scattering albedo peaking at ω = 0.955 ± 0.004. Concurrently, number concentration and size peaked with maximum Dp = 126 nm and a unimodal distribution with σg = 1.5. Long‐range transported smoke was substantially diluted (Ntot factor of 7 lower) and shifted larger (maximum Dp = 143) and wider (σg = 2.2). We compared ambient data to laboratory burns with representative western U.S. forest fuels (coniferous species Ponderosa pine and Alaska black spruce). Smoldering pine produced an aerosol dominated by larger, more strongly light scattering particles (Dp > 100 nm), while flaming combustion produced very high number concentrations of smaller (Dp ~ 50 nm) absorbing particles. Due to smoldering and particle growth processes, Dp approached 100 nm within 3 h after emission. Increased particle cross‐sectional area and Mie scattering efficiency shifted the relative importance of light absorption (flaming maximum) and light scattering (smoldering maximum), increasing ω over time. Measurements showed a consistent picture of smoke properties from emission to aging.

Holocene fire-regime changes near the treeline in the Retezat Mts. (Southern Carpathians, Romania)

To investigate Holocene vegetation and fire-disturbance histories in the treeline ecotone, macroscopic charcoal, plant-macrofossil, and pollen records from two lacustrine sediment records were used. Lake Lia is on the southern slope and Lake Brazi is on the northern slope of the west-east-oriented Retezat Mountain range in the Romanian Carpathians. The records were used to reconstruct Holocene fire-return intervals (FRIs) and biomass burning changes. Biomass burning was highest at both study sites during the drier and warmer early Holocene, suggesting that climate largely controlled fire occurrence. Fuel load also influenced the fire regime as shown by the rapid biomass-burning changes in relation to timberline shifts. Overall, the number of inferred fire episodes was smaller on the northern than on the southern slope. FRIs were also comparatively longer (1000–4000 years) on the northern slope where Picea abies-dominated woodlands persisted around Lake Brazi throughout the Holocene. On the southern slope, where Pinus mugo was more abundant around Lake Lia, FRIs were significantly shorter (80–1650 years). A period of frequent fire episodes occurred around 1900–1300 cal yr BP on the southern slope, when chironomid-inferred summer temperatures increased and the pollen record documents increased anthropogenic activity near the treeline. However, the forest clearance by burning to increase grazing land was subdued in comparison to other European regions.

Historical records of mercury in southern latitudes over 1600 years: Lake Futalaufquen, Northern Patagonia

Mercury is released to the environment from natural and anthropogenic sources, and through atmospheric transport is distributed globally. Lake Futalaufquen (42.8°S) is an oligotrophic lake located in Los Alerces National Park (Northern Patagonia), providing a remote and unpolluted study system. A lacustrine sedimentary sequence revealed 1600years of Hg deposition, identifying natural baselines and marked peaks not correlated with long-range atmospheric transport. Organic matter and catchment erosion were discarded as Hg drivers. Natural background, pre-1300CE Hg concentrations, ranged between 27 and 47ngg−1 (accumulation rates from 8 to 15μgm−2y−1). From 1300CE on, the Hg background profile did not follow the generally increasing Hg pattern observed in both Southern and Northern Hemisphere since pre-industrial times. It was not until the last century that a 1.6-fold increase is observed in the Hg accumulation rate, considered among the lowest increments in southern South America. Noteworthy local/regional sources of Hg for this area, along with global transport, are forest fires and volcanic activity. Between approx. 1340 and 1510CE, sharp increase in Hg concentration and accumulation rate (up to 204ngg−1 and 51μgm−2y−1, respectively) were clearly associated with extended fire episodes. Furthermore, high Hg peaks during the last 300years were associated with volcanic eruptions in northernmost Patagonia together with fairly irregular fire episodes, caused by anthropogenic burning by settling population in the Andes.

Reconstructing Fire Records from Ground-Based Routine Aerosol Monitoring

Long-term fire records are important to understanding the trend of biomass burning and its interactions with air quality and climate at regional and global scales. Traditionally, such data have been compiled from ground surveys or satellite remote sensing. To obtain aerosol information during a fire event to use in analyzing air quality, we propose a new method of developing a long-term fire record for the contiguous United States using an unconventional data source: ground-based aerosol monitoring. Assisted by satellite fire detection, the mass concentration, size distribution, and chemical composition data of surface aerosols collected from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network are examined to identify distinct aerosol characteristics during satellite-detected fire and non-fire periods. During a fire episode, elevated aerosol concentrations and heavy smoke are usually recorded by ground monitors and satellite sensors. Based on the unique physical and chemical characteristics of fire-dominated aerosols reported in the literature, we analyzed the surface aerosol observations from the IMPROVE network during satellite-detected fire events to establish a set of indicators to identify fire events from routine aerosol monitoring data. Five fire identification criteria were chosen: (1) high concentrations of PM2.5 and PM10 (particles smaller than 2.5 and 10 in diameters, respectively); (2) a high PM2.5/PM10 ratio; (3) high organic carbon (OC/PM2.5) and elemental carbon (EC/PM2.5) ratios; (4) a high potassium (K/PM2.5) ratio; and (5) a low soil/PM2.5 ratio. Using these criteria, we are able to identify a number of fire episodes close to 15 IMPROVE monitors from 2001 to 2011. Most of these monitors are located in the Western and Central United States. In any given year within the study period fire events often occurred between April and September, especially in the two months of April and September. This ground-based fire climatology is also consistent with that derived from satellite retrievals. This study demonstrates that it is feasible to reconstruct historic records of fire events based on continuous ground aerosol monitoring. This dataset can provide not only fire activity information but also fire-induced aerosol surface concentrations and chemical composition that can be used to verify satellite-based products and evaluate air quality and climate modeling results. However, caution needs to be exercised because these indicators are based on a limited number of fire events, and the proposed methodology should be further tested and confirmed in future research.

Impact of the New South Wales fires during October 2013 on regional air quality in eastern Australia

Smoke plumes from fires contain atmospheric pollutants that can be transported to populated areas and effect regional air quality. In this paper, the characteristics and impact of the fire plumes from a major fire event that occurred in October 2013 (17–26) in the New South Wales (NSW) in Australia, near the populated areas of Sydney and Wollongong, are studied. Measurements from the Fourier Transform InfraRed (FTIR) spectrometer located at the University of Wollongong allowed a calculation of specific emission factors (EFs) in terms of grams per kilogram of dry fuel burned: 1640 g kg−1 of carbon dioxide; 107 g kg−1 of carbon monoxide; 7.8 g kg−1 of methane; and 0.16 g kg−1 of nitrous oxide. These EFs have then been used to calculate daily fire emissions for the NSW fire event using the APIFLAME emissions' model, leading to an increase of 54% of CO emitted compared to calculations with EFs from Akagi et al. (2011), widely used in the literature.Simulations have been conducted for this event using the regional chemistry-transport model (CTM) CHIMERE, allowing the first evaluation of its regional impact. Fire emissions are assumed well mixed into the boundary layer. The model simulations have been evaluated compared to measurements at the NSW air quality stations. The mean correlation coefficients (R) are 0.44 for PM10, 0.60 for PM2.5 and 0.79 for CO, with a negative bias for CO (−14%) and a positive bias for PM2.5 (64%). The model shows higher performance for lower boundary layer heights and wind speeds. According to the observations, 7 days show concentrations exceeding the air quality Australian national standards for PM10, 8 days for PM2.5. In the simulations, 5 days are correctly simulated for PM10, 8 days for PM2.5. For PM10, the model predicts 1 additional day of exceedance (one false detection). During this fire episode, inner Sydney is affected during 5 days by PM exceedances, that are mainly attributed to organic carbon in the model simulations.To evaluate the influence of the diurnal variability and the injection heights of fire emissions, two additional simulations were performed: one with all fire emissions injected below 1 km (CHIM_1 km), since satellite observations suggest low injection for this fire case, and one with a diurnal profile (CHIM_diu) adjusted to best match surface observations closest to the fires. CHIM_1 km displays less bias and root mean square error, and CHIM_diu presents a good agreement for hourly statistics for stations where peaks of PM are well captured, but enhances the differences when a peak is overestimated by the model. This sensitivity analysis highlights significant uncertainties related to these two key fire parameters (which add up to uncertainties on emissions), resulting in variations on concentrations of PM and CO.

Somatic Embryogenesis of Abies cephalonica Loud.

Greek fir (Abies cephalonica Loudon) belongs to the Mediterranean fir species and is widely distributed in the mountains of Central and Southern Greece. Considering a climatic scenario, infestation by pathogens or insects and fire episodes, it has been proposed that Mediterranean firs could be in danger in some parts of their present range but, on the other hand, could also replace other species in more northern zones with temperate humid climates (e.g., silver fir, Abies alba Mill.). As fir species are generally highly productive and therefore important for commercial forestry, they have traditionally been involved in conventional tree improvement programs. A lot of effort has been put into the development of vegetative propagation methods for firs, in order to rapidly gain the benefits of traditional breeding to be utilized in reforestation. The present paper provides up to date information on protocols for somatic embryogenesis (i.e., the most promising in vitro method for vegetative propagation) of Greek fir. Moreover, the protocols for cryopreservation and long-term storage of embryogenic material are described as well.

Forest Fire and its Impact on Deforestation and Environment of Uttarakhand

Of all environmental degradation problems facing the Himalaya are its various forms and results, the forest depletion has been most acute and attained the most dangerous level in the Himalayan region. In past few decades the rapid growth of population and expectation have led to the increased use of forest to such an extent that the forest in many places have disappeared. The ecological and hydrological consequences of deforestation are the present conditions of large-scale aridification and even desertification. The forest cover has already depleted in the Himalayan region due to forest fire, which is not an independent force in nature, being one of the major factors which can affect every aspect of forest ecology and contribute towards the disappearance of forests. The present paper clearly indicated the major fire episodes and impact on deforestation.