Increasing Frequency Of Wildfires Research Articles

Wildfires Influence Mercury Transport, Methylation, and Bioaccumulation in Headwater Streams of the Pacific Northwest.

The increasing frequency and severity of wildfires are among the most visible impacts of climate change. However, the effects of wildfires on mercury (Hg) transformations and bioaccumulation in stream ecosystems are poorly understood. We sampled soils, water, sediment, in-stream leaf litter, periphyton, and aquatic invertebrates in 36 burned (one-year post fire) and 21 reference headwater streams across the northwestern U.S. to evaluate the effects of wildfire occurrence and severity on total Hg (THg) and methylmercury (MeHg) transport and bioaccumulation. Suspended particulate THg and MeHg concentrations were 89 and 178% greater in burned watersheds compared to unburned watersheds and increased with burn severity, likely associated with increased soil erosion. Concentrations of filter-passing THg were similar in burned and unburned watersheds, but filter-passing MeHg was 51% greater in burned watersheds, and suspended particles in burned watersheds were enriched in MeHg but not THg, suggesting higher MeHg production in burned watersheds. Among invertebrates, MeHg in grazers, filter-feeders, and collectors was 33, 48, and 251% greater in burned watersheds, respectively, but did not differ in shredders or predators. Thus, increasing wildfire frequency and severity may yield increased MeHg production, mobilization, and bioaccumulation in headwaters and increased transport of particulate THg and MeHg to downstream environments.

Multitemporal Dynamics of Fuels in Forest Systems Present in the Colombian Orinoco River Basin Forests

In Colombia’s Orinoco, wildfires have a profound impact on ecosystem dynamics, particularly affecting savannas and forest–savanna transitions. Human activities have disrupted the natural fire regime, leading to increased wildfire frequency due to changes in land use, deforestation, and climate change. Despite extensive research on fire monitoring and prediction, the quantification of fuel accumulation, a critical factor in fire incidence, remains inadequately explored. This study addresses this gap by quantifying dead organic material (detritus) accumulation and identifying influencing factors. Using Brown transects across forests with varying fire intensities, we assessed fuel loads and characterized variables related to detritus accumulation over time. Employing factor analysis, principal components analysis, and a generalized linear mixed model, we determined the effects of various factors. Our findings reveal significant variations in biomass accumulation patterns influenced by factors such as thickness, wet and dry mass, density, gravity, porosity, and moisture content. Additionally, a decrease in fuel load over time was attributed to increased precipitation from three La Niña events. These insights enable more accurate fire predictions and inform targeted forest management strategies for fire prevention and mitigation, thereby enhancing our understanding of fire ecology in the Orinoco basin and guiding effective conservation practices.

Formation of secondary organic aerosols from Cl-initiated oxidation of anisole: Rapid release of ultrafine particles and organic chlorides

Recent studies have highlighted the increased occurrence of reactive chlorine, drawing significant attention to the process of chlorinated chemical oxidation of oxygenated aromatics emitted from biomass burning (BB) in the formation of secondary organic aerosols (SOA). This study selected an oxygenated aromatic, anisole, as a representative of BB, and investigated the products and mechanisms of its reaction with Cl•, as well as exploring the implications of precursor-to-oxidant ratio ([anisole/Cl2]0), NOx levels, and seed particles on SOA generation. The gas-phase composition, SOA composition, and particle information were determined using a single-photon ionization time-of-flight mass spectrometry (SPIMS), a thermal desorption unit gas chromatography mass spectrometry (TDU-GC/MS), and a scanning mobility particle sizer (SMPS), respectively. Experimental results indicate that within minutes of turning on the ultraviolet (UV) lights, a large quantity of ultrafine particles (UFPs) (diameter <100 nm) is immediately formed. The SOA yield is significantly dependent on [anisole/Cl2]0, decreasing from 66.2% to 20.0% as the [anisole/Cl2]0 increases. Upon oxidation by Cl•, anisole promptly released organic chlorides, including 2-chlorophenol and 2,4,6-trichlorophenol. The addition of NOx decreased the SOA yield, enhanced the role of OH• in the reaction process, and led to the formation of organic nitrogen products, such as C6H5NO3 and C7H7NO4. Furthermore, Cl• primarily initiates reactions through H-abstraction and Cl-substitution, resulting in the oxidation products largely retaining the benzene ring. This provides a potential explanation for the high SOA yield induced by Cl• in this study. Overall, our work suggests that the release of UFPs and organic chlorides can be found in the Cl-initiated oxidation of anisole, which contributes to high SOA yields. Against the backdrop of increasing wildfire frequency due to global warming, it is necessary to consider the contributions and sources of UFPs and organic chlorides caused by the reaction of wildfire emissions with Cl atoms.

Appearance of Recalcitrant Dissolved Black Carbon and Dissolved Organic Sulfur in River Waters Following Wildfire Events.

Increasing wildfire frequency, a consequence of global climate change, releases incomplete combustion byproducts such as aquatic pyrogenic dissolved organic matter (DOM) and black carbon (DBC) into waters, posing a threat to water security. In August 2022, a series of severe wildfires occurred in Chongqing, China. Samples from seven locations along the Yangtze and Jialing Rivers revealed DBC, quantified by the benzene poly(carboxylic acid) (BPCA) method, comprising 9.5-19.2% of dissolved organic carbon (DOC). High concentrations of BPCA-DBC with significant polycondensation were detected near wildfire areas, likely due to atmospheric deposition driven by wind. Furthermore, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) revealed that wildfires were associated with an increase in condensed aromatics, proteins, and unsaturated hydrocarbons, along with a decrease in lignins. The condensed aromatics primarily consisted of dissolved black nitrogen (DBN), contributing to abundant high-nitrogen-containing compounds in locations highly affected by wildfires. Meanwhile, wildfires potentially induced the input of recalcitrant sulfur-containing protein-like compounds, characterized by high oxidation, aliphatic nature, saturation, and low aromaticity. Overall, this study revealed the appearance of recalcitrant DBC and dissolved organic sulfur in river waters following wildfire events, offering novel insights into the potential impacts of wildfires on water quality and environmental biogeochemistry.

The importance of habitat type and historical fire regimes in arthropod community response following large-scale wildfires.

Novel wildfire regimes are rapidly changing global ecosystems and pose significant challenges for biodiversity conservation and ecosystem management. In this study, we used DNA metabarcoding to assess the response of arthropod pollinator communities to large-scale wildfires across diverse habitat types in California. We sampled six reserves within the University of California Natural Reserve System, each of which was partially burned in the 2020 Lightning Complex wildfires in California. Using yellow pan traps to target pollinators, we collected arthropods from burned and unburned sites across multiple habitat types including oak woodland, redwood, scrub, chamise, grassland, forest, and serpentine habitats. We found no significant difference in alpha diversity values between burned and unburned sites; instead, seasonal variations played a significant role in arthropod community dynamics, with the emergence of plant species in Spring promoting increased pollinator richness at all sites. When comparing all sites, we found that burn status was not a significant grouping factor. Instead, compositional differences were largely explained by geographic differences, with distinct communities within each reserve. Within a geographic area, the response of arthropods to fire was dependent on habitat type. While communities in grasslands and oak woodlands exhibited recovery following burn, scrublands experienced substantial changes in community composition. Our study highlights the importance of examining community responses to wildfires across broad spatial scales and diverse habitat types. By understanding the nuanced dynamics of arthropod communities in response to fire disturbances, we can develop effective conservation strategies that promote resilience and maintain biodiversity in the face of increasing wildfire frequency and severity driven by climate change.

The effects of wildfire frequency on post-fire soil surface water dynamics

Increasing wildfire frequency in the Mediterranean Basin could affect future plant-soil–water-dynamics. The capacity of soils to retain water is a key parameter affecting plant post-fire regeneration. Yet, few research has looked at how different soil properties related to water retention is affected by increasing wildfire frequency. This study aimed at understanding the relationship between wildfire frequency, soil–water-related properties and the dynamics of surface water in soils. To this, after a 2012-summer wildfire in Portugal, three sets of three replicate maritime pine stands with contrasted wildfire frequency were selected (0 vs. 1 vs. 4 fires since 1975). At each of the nine study sites, three re-sprouter shrubs and neighbouring bare soil were chosen (54 microsites). There, soil cover, soil–water retention curves and surface (0–5 cm) soil–water-related properties (texture, bulk density, organic matter content, soil moisture, soil surface water repellency) were monitored for one year. Furthermore, records of post-fire soil moisture dynamics were analysed continuously using 72 probes installed at 2.5 and 7.5 cm depth. The hillslopes affected by 1 fire showed higher plant recovery than the 4 fires hillslopes. During the dry season, the threshold for water stress was reached 17 days sooner in the 4 fires hillslopes, and also 10 days sooner on bare microsites. Periods of plant water stress were longer and bare soil patches size bigger. The increase in wildfire frequency promoted high soil organic matter contents but less available water content, stressing the importance of soil organic matter quality characterization in water-related properties.

Wyoming Big Sagebrush Transplant Survival and Growth Affected by Age, Season of Planting, and Competition

Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis [Beetle & A. Young] S. L. Welsh) has decreased from its historic prevalence across the sagebrush steppe in part because of its interaction with invasive annual grasses and the increased wildfire frequency. Restoration of this species is vital to the ecosystem; however, traditional seeding methods such as broadcast or drill seeding have low success rates. Seedling mortality is associated with harsh weather conditions such as freezing temperatures in the winter and extreme temperature and soil moisture conditions during the summer drought. Transplanting sagebrush has greater success by overcoming the bottleneck of early seedling mortality. We tested how sagebrush transplant survival and size (canopy volume) are affected by age at the time of planting (10 classes, 6−24 wk), planting season (fall versus spring), and invasive annual grass competition (low/high) with a randomized factorial design over 2 yr. Survival was lower for age classes under 10 or 12 wk (in yr 1 and 2, respectively) but relatively similar from 12 to 24 wk. Fall-planted transplants had lower survival but increased canopy volume compared with spring-planted transplants. Survival and canopy volume decreased with competition with annual grasses. Our results suggest that land managers should consider planting younger transplants than previously thought and controlling invasive annual grasses before planting sagebrush transplants to increase long-term survival and canopy volume.

Tundra fire increases the likelihood of methane hotspot formation in the Yukon–Kuskokwim Delta, Alaska, USA

Rapid warming in Arctic tundra may lead to drier soils in summer and greater lightning ignition rates, likely culminating in enhanced wildfire risk. Increased wildfire frequency and intensity leads to greater conversion of permafrost carbon to greenhouse gas emissions. Here, we quantify the effect of recent tundra fires on the creation of methane (CH4) emission hotspots, a fingerprint of the permafrost carbon feedback. We utilized high-resolution (∼25 m2 pixels) and broad coverage (1780 km2) airborne imaging spectroscopy and maps of historical wildfire-burned areas to determine whether CH4 hotspots were more likely in areas burned within the last 50 years in the Yukon–Kuskokwim Delta, Alaska, USA. Our observations provide a unique observational constraint on CH4 dynamics, allowing us to map CH4 hotspots in relation to individual burn events, burn scar perimeters, and proximity to water. We find that CH4 hotspots are roughly 29% more likely on average in tundra that burned within the last 50 years compared to unburned areas and that this effect is nearly tripled along burn scar perimeters that are delineated by surface water features. Our results indicate that the changes following tundra fire favor the complex environmental conditions needed to generate CH4 emission hotspots. We conclude that enhanced CH4 emissions following tundra fire represent a positive feedback that will accelerate climate warming, tundra fire occurrence, and future permafrost carbon loss to the atmosphere.

Wildfire immediately reduces nest and adult survival of greater sage-grouse

Wildfire events are becoming more frequent and severe on a global scale. Rising temperatures, prolonged drought, and the presence of pyrophytic invasive grasses are contributing to the degradation of native vegetation communities. Within the Great Basin region of the western U.S., increasing wildfire frequency is transforming the ecosystem toward a higher degree of homogeneity, one dominated by invasive annual grasses and declining landscape productivity. Greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse) are a species of conservation concern that rely on large tracts of structurally and functionally diverse sagebrush (Artemisia spp.) communities. Using a 12-year (2008–2019) telemetry dataset, we documented immediate impacts of wildfire on demographic rates of a population of sage-grouse that were exposed to two large wildfire events (Virginia Mountains Fire Complex—2016; Long Valley Fire—2017) near the border of California and Nevada. Spatiotemporal heterogeneity in demographic rates were accounted for using a Before-After Control-Impact Paired Series (BACIPS) study design. Results revealed a 40% reduction in adult survival and a 79% reduction in nest survival within areas impacted by wildfires. Our results indicate that wildfire has strong and immediate impacts to two key life stages of a sagebrush indicator species and underscores the importance of fire suppression and immediate restoration following wildfire events.

Cascading effects of climate change and wildfire on a subarctic lake: A 20‐year case study of watershed change

AbstractMean annual air temperature has been increasing in Alaska since the 1970s and is expected to continue to increase through the current century, resulting in significant environmental changes (e.g., permafrost thaw, shifts in vegetation community composition and distribution, increased wildfire frequency and severity). Because there is little long‐term monitoring data available on lake ecosystems in the subarctic it is difficult to predict how lakes will respond. Here we present data from an ~20‐year long‐term lake and climate monitoring program in Interior Alaska. A significant portion of the lake catchment was burned by wildfires in 1986 and again in 2004. As a result, much of the vegetation in the lake catchment was converted from spruce‐dominated forest to deciduous forest, indicating likely permafrost degradation. At a nearby monitoring site absent of fire effects, mean annual ground temperatures at 50 and 90 cm warmed significantly from about −2°C to about −1°C over the 20‐year monitoring period. Warming of similar or greater magnitude is inferred at the study site due to fire effects. Lake water analyses before and after the 2004 fire show a significant postfire increase in dissolved organic carbon, total nitrogen, and total phosphorous that persisted for a short period (~3 years) and was followed by small, but significant, increases in specific conductance and ion concentrations. Approximately 15 years postfire sulfate and cation concentrations in the lake increased exponentially due to the development of a groundwater seep near the lake. The seep likely formed as a result of permafrost thaw creating new subsurface flowpaths in response to long‐term climate warming and fire effects. In 2021, specific conductance and sulfate concentrations reached 657 μS/cm and 71 mg/L respectively, exceeding tolerance thresholds of the water lily Nuphar lutea. In 2021, N. lutea beds that had occupied the lake since 1981 were no longer visible. Depending on local catchment characteristics, source waters and flow paths contributing to small subarctic lakes will continue to evolve uniquely in response to climate change and thawing permafrost. This case study shows the cascading effects of warming soil and wildfires on catchment characteristics as well as terrestrial and aquatic vegetation and lake water chemistry.

Tissue-Level Flammability Testing: A Review of Existing Methods and a Comparison of a Novel Hot Plate Design to an Epiradiator Design

Increased wildfire frequency and size has led to a surge in flammability research, most of which investigates landscape-level patterns and wildfire dynamics. There has been a recent shift towards organism-scale mechanisms that may drive these patterns, as more studies focus on flammability of plants themselves. Here, we examine methods developed to study tissue-level flammability, comparing a novel hot-plate-based method to existing methods identified in a literature review. Based on a survey of the literature, we find that the hot plate method has advantages over alternatives when looking at the specific niche of small-to-intermediate live fuel samples—a size range not addressed in most studies. In addition, we directly compare the hot plate method to the commonly used epiradiator design by simultaneously conducting flammability tests along a moisture gradient, established with a laboratory benchtop drydown. Our design comparison addresses two basic issues: (1) the relationship between hydration and flammability and (2) relationships between flammability metrics. We conclude that the hot plate method compares well to the epiradiator method, while allowing for testing of bigger samples.

Soil biogeochemistry and microbial community dynamics in Pinus pinaster Ait. forests subjected to increased fire frequency

Fire frequency might increase in many fire-dominated ecosystems of the world due to the combined effects of global warming, land-use change and increased human pressures. Understanding how changes in fire frequency can affect the main soil biogeochemical dynamics, as well as the microbial community, in the long term is utmost important. Here we determined the effect of changes in fire frequency and other fire history characteristics on soil C and N dynamics and the main microbial groups (using soil fatty acid profiles), in Pinus pinaster forests from central Spain. Stands were chosen to differ in the number of fires (1 to 3) occurred between 1976 and 2018, in the time elapsed since the last fire and the interval undergone between the last two consecutive fires. We found that, in general, most of the studied biogeochemical and microbial variables showed clear differences between unburned and burned stands. The time elapsed since the last fire was the most important fire history covariable and governed the main soil nutrient dynamics and microbial groups. Recovery to pre-fire values took 30–40 years. Increased wildfire frequency only modified total C and nitrification rate, but results were not consistent between stands burned twice and thrice. The time interval (years) between the last two fires was not a significant covariable. The fact that some stands burnt up to thrice in a period of 43 years supports the strong capacity of this ecosystem to recover, even under an increased fire frequency.

Wildfire response to rapid climate change during the Permian-Triassic biotic crisis

Char and polycyclic aromatic hydrocarbons (PAHs), which can serve as proxies for wildfire frequency and/or intensity, are widely present in Permian-Triassic boundary (PTB) strata, providing information on volcanism or on climatic control of fuel availability (linked to vegetation type and density) or combustibility (linked to aridity). Here, we present evidence to separate temporal from geographic signals of climate impact on wildfire during the Permian-Triassic (P-Tr) transition. Geographically, char and pyrolytic PAHs for wildfire are concentrated in temperate and tropical regions and show a connection with forest distribution as reflected by occurrences of Upper Permian coals. Temporally, the subtropical terrestrial Dalongkou section of northwestern China provides evidence of two intervals of increased pyrolytic PAHs of combustion origin. The first interval was linked to climatic hyperwarming during the latest Permian, whereas the second interval was associated with rapid climatic drying, as recorded by spore-to-pollen ratios (S/P), during the P-Tr transition. This record suggests that rapid climate change during the P-Tr transition increased wildfire frequency. A climate link is also shown by turnovers of ostracods, conchostracans, and charophytes in conjunction with greater wildfire frequency. The trigger for enhanced wildfires and biotic changes is inferred to have been volcanically induced climatic warming and aridification. Our data thus document important links between wildfires, climate change, volcanism, and mass extinction during the P-Tr transition.

Polycyclic Aromatic Compounds in Rivers Dominated by Petrogenic Sources after a Boreal Megafire.

Polycyclic aromatic compounds (PACs) threaten the health of aquatic ecosystems. In northeastern Alberta, Canada, decades of oil sands mining and upgrading activities have increased PAC delivery into freshwaters. This PAC pollution adds to natural inputs from river erosion of bitumen-bearing McMurray Formation outcrops and wildfire inputs. Quantifying these petrogenic and pyrogenic PAC inputs, which is key for understanding industrial impacts, remains a challenge. To distinguish petrogenic from pyrogenic inputs, we characterized river water PACs before and after the 2016 Fort McMurray wildfire, one of the largest natural disasters in Canadian history. Samples of wildfire ash and outcropping bitumen allow us to distinguish between these important PAC sources. River PAC concentrations ranged over multiple orders of magnitude (10s-10 000s ng/L). Petrogenic PACs dominated most of the postfire period with only short-term episodes of pyrogenic signatures in burned watersheds due to the wash-in of ash from the watershed. Wildfire PAC inputs during these events resulted in exceptional increases in concentrations that met or exceeded high (petrogenic) background concentrations, driven by the natural erosion of outcropping bitumen. Our dataset offers the first quantification of these two important PAC sources in this industrialized region and provides new insight into the impacts of increasing wildfire frequency and severity across the Boreal Forest.

Forest fire effects on stream water quality at continental scales: a meta-analysis

Forested watersheds supply over two thirds of the world’s drinking water. The last decade has seen an increase in the frequency and intensity of wildfires that is threatening these source watersheds, and necessitating more expensive water treatment to address degrading water quality. Given increasing wildfire frequency in a changing climate, it is important to understand the magnitude of water quality impacts following fire. Here, we conducted a meta-analysis to explore post-fire changes in the concentrations of nitrogen (N) and phosphorus (P) species, dissolved organic carbon, and total suspended sediments in 121 sites around the world. Changes were documented over each study’s respective duration, which for 90% of sites was five years or fewer. We find concurrent increases in C, N and P species, highlighting a tight coupling between biogeochemical cycles in post-fire landscapes. We find that fire alters N and P speciation, with median increases of 40%–60% in the proportion of soluble inorganic N and P relative to total N and P. We also found that fire decreases C:N and C:P ratios, with median decreases ranging from 60% to 70%. Finally we observe a ‘hockey stick’-like response in changes to the concentration distribution, where increases in the highest concentration ranges are much greater than increases at lower concentrations. Our study documents strong heterogeneity in responses of water quality to wildfire that have been unreported so far in the literature.

Assessing the Role of Snow Cover for Post‐Wildfire Revegetation Across the Pacific Northwest

AbstractForested, mountain landscapes in the Pacific Northwest (PNW) are changing at an unprecedented rate, largely due to shifts in the regional climate regime. Documented climate warming trends across the PNW include increasing wildfire frequency and severity and an increasingly ephemeral snowpack, especially at moderate elevations. We analyzed 24 high severity wildfires across four distinct PNW mountainous subregions, examining snow‐vegetation relationships for two years pre‐fire and four years post‐fire. To assess the importance of snow cover for revegetation compared to other climatic, topographic, and burn severity‐related variables, binary regression tree models were constructed for the dominant pre‐fire conifer species within each of the four PNW subregions. Summer precipitation consistently appeared as the most important variable driving post‐fire revegetation across all four subregions. Snow cover variables (snow cover frequency and snow disappearance date), along with elevation, were shown to be secondary but significantly influential explanatory variables for revegetation in the Oregon and Washington Cascades. Revegetation was also analyzed using a time series of linear regressions across 200‐m elevation bands by measuring correlations between winter snow cover and summer vegetation greenness. Results showed strong positive post‐fire correlations at moderate elevations in the western Montana Rockies and at the lowest elevation band in the Idaho Rockies. Considering trends of increasing wildfire activity, lower snowpacks, and earlier snow disappearance dates across the PNW, forests will likely experience more frequent drought conditions that will impact post‐wildfire vegetation regrowth.

Avian Response to Wildfire Severity in a Northern Boreal Region

Research Highlights: The effects of fire on birds in the most northern parts of the boreal forest are understudied. We found distinct differences in bird communities with increasing fire severity in two vegetation types with naturally different burn severity. The highest severity burns tended to have communities dominated by generalist species, regardless of the original vegetation type. Background and Objectives: Wildfire is the primary natural disturbance in the boreal ecosystems of northwestern Canada. Increased wildfire frequency, extent, and severity are expected with climate change in this region. In particular, the proportion of burns that are high severity and the area of peatlands burned are increasing, and how this influences birds is poorly understood. Materials and Methods: We quantified the effects of burn severity (low, moderate, and high severity) in uplands and peatlands on occupancy, density, richness, community composition, and functional diversity using point counts (n = 1158) from the first two years post-fire for two large fires in the Northwest Territories, Canada. Results: Burn severity had a significant effect on the occupancy and density of 86% of our focal species (n = 20). Responses to burn severity depended on vegetation type for four of the 18 species using occupancy and seven of the 18 using density, but were typically in a similar direction. Species richness and functional diversity were lower in areas of high severity burns than unburned areas and low severity burns in peatlands. Richness was not related to severity in uplands, but functional diversity was. Peatlands had higher species richness than uplands in all burn severities, but as burn severity increased the upland and peatland communities became more similar. Conclusions: Our results suggest that high severity burns in both vegetation types support five generalist species and two fire specialists that may benefit from alterations in vegetation structure as a result of climate induced changes to fire regimes. However, eight species avoided burns, particularly birds preferring peatlands, and are likely to be more susceptible to fire-driven changes to their habitat caused by climate change. Understanding the long-term risks to these species from climate change requires additional efforts that link fire to bird populations.

Ormanlarda iklim değişikliğinin etkilerinin belirlenmesinde bazı önemli parametreler: Cerle planlama birimi örneği, Antalya, Türkiye

Climate change is one of the most detrimental issues of the earth in this century. It is evident that a change in climate parameters would affect considerably the entire global ecosystem’s environment. On the other hand, different forest related parameters such as natural disaster occurrence or land cover change of forest ecosystems could also help to understand the effects of climate change besides climate parameters such as temperature, precipitation or relative humidity. Therefore, in this study, selected parameters describing climate change were tried to display in a Mediterranean forest planning unit called “Cerle” located in Antalya. Firstly, trend analysis was carried out using climate parameters in the selected study area to detect the amount of climate change. Then, different natural disaster occurrences such as forest fire, windstorm, insects and pest attack evolution were displayed over a period of 30 to 50 years. Spatiotemporal changes for the same period were also tried to be demonstrated, based on historical and actual maps to identify the impact of climate change on the structure and composition of forest ecosystems. In brief, Mann-Kendall test results showed significant increasing trends in annual mean temperature and precipitation. Moreover, the natural development of crimean pine as a result of land use change analysis, as well as the increasing frequency of wildfires and windstorm leading to salvage cutting have been interpreted as the impact of climate change. It is concluded that changes in selected climate parameters are very important to display the climate change digitally. The outputs of this study could help in future forest management planning decisions and determination of silvicultural prescriptions. Furthermore, the obtained results might be the basis for the integration of climate change to forest management planning related to future climate projections and scenarios.

Pre-Columbian Fire Management Linked to Refractory Black Carbon Emissions in the Amazon

Anthropogenic climate change—combined with increased human-caused ignitions—is leading to increased wildfire frequency, carbon dioxide emissions, and refractory black carbon (rBC) aerosol emissions. This is particularly evident in the Amazon rainforest, where fire activity has been complicated by the synchronicity of natural and anthropogenic drivers of ecological change, coupled with spatial and temporal heterogeneity in past and present land use. One approach to elucidating these factors is through long-term regional fire histories. Using a novel method for rBC determinations, we measured an approximately 3500-year sediment core record from Lake Caranã in the eastern Amazon for rBC influx, a proxy of biomass burning and fossil fuel combustion. Through comparisons with previously published records from Lake Caranã and regional evidence, we distinguished between local and regional rBC emission sources demonstrating increased local emissions of rBC from ~1250 to 500 calendar years before present (cal yr BP), coinciding with increased local-scale fire management during the apex of pre-Columbian activity. This was followed by a regional decline in biomass burning coincident with European contact, pre-Columbian population decline, and regional fire suppression associated with the rubber boom (1850–1910 CE), supporting the minimal influence of climate on regional burning at this time. During the past century, rBC influx has rapidly increased. Our results can serve to validate rBC modeling results, aiding with future predictions of rBC emissions and associated impacts to the climate system.

The compounding consequences of wildfire and climate change for a high‐elevation wildflower (Saxifraga austromontana)

AbstractAimHigh‐elevation plants are disproportionally affected by climate change. As temperatures rise, the amount of available alpine habitat in the Rocky Mountains will decrease resulting in potential local extinctions of plant species. In addition to the direct effects of climate‐driven habitat loss, alpine plants must also respond to indirect effects, such as changes in disturbance regimes. One notable shift is the increase of wildfire frequency in regions where fire was previously rare or absent, including the alpine. We hypothesized that direct climatic changes compounded with increased wildfire frequency will reduce the future suitable habitat of high‐elevation plants more than if climate was considered alone.LocationRocky Mountain Floristic Region, western North America.TaxonSaxifraga austromontana (Saxifragaceae), a wildflower endemic to high elevations of the Rocky Mountain Floristic Region.MethodsOur approach integrated historical herbarium records, field surveys, remote sensing, species distribution models, historic wildfire data, and predictive models.ResultsOur results indicate wildfire has significantly reduced the abundance and increased the likelihood of extirpation for S. austromontana. Increased fire frequency compounded with direct climatic changes will likely reduce the range of the species by approximately 43% by 2050 compared to 38% due to climate alone, under a moderate CO2 emissions scenario. The influence of wildfire varies regionally. For instance, the Middle Rockies will likely lose 74% of its suitable habitat of which 16% may be lost due to fire, while other regions, such as the northern range, will be less negatively affected by direct and indirect effects.Main ConclusionsOur evidence that increased wildfire frequency will compound the impacts of climate change on alpine taxa in North America led to the development of a new, general hypothesis on the fundamental interaction between direct and indirect effects of climate change on species range reductions.