Road network density correlated with increased lightning fire incidence in the Canadian western boreal forest

2009 ◽  
Vol 18 (8) ◽  
pp. 970 ◽  
Author(s):  
M. Cecilia Arienti ◽  
Steven G. Cumming ◽  
Meg A. Krawchuk ◽  
Stan Boutin
Keyword(s):  
Boreal Forests ◽  
Negative Binomial ◽  
Fire Regime ◽  
Positive Association ◽  
Fire Frequency ◽  
Forest Composition ◽  
Road Density ◽  
Linear Features ◽  
Linear Feature ◽  
Lightning Fire

This paper quantifies the influence of anthropogenic linear disturbances on fire ignition frequency in the boreal forests of western Canada. Specifically, we tested if linear features increase the frequency of lightning fires, and whether this relationship is affected by spatial resolution. We considered fires that ignited between 1995 and 2002 within a ~67 000 km2 region of boreal mixed-wood forest in north-eastern Alberta where linear features are highly abundant and spatially heterogeneous. We constructed Poisson, Negative Binomial and Zero-Inflated Poisson models at two spatial resolutions (~10 000 and ~2400 ha), including covariates for linear feature densities, forest composition, weather–lightning indices and geography. We found a positive association between lightning fire frequency and road density; this association was consistent at both spatial resolutions. We suggest this occurs owing to increased availability of flammable fine fuels near roads. The effect was attributable neither to increased detectability of fires proximal to roads by human observers, nor to increased lightning strikes due to metallic infrastructure alongside roads or the topographic characteristics of road location. Our results suggest that, in the face of projected road developments in the region, the potential exists for important changes to the regional fire regime. Further research should elucidate the precise mechanisms in order to develop methods for mitigation.

Interaction between peatland moisture and plant functional types drives fire dynamics in forested peatlands in central-western Siberia

2021 ◽  
Author(s):  
Angelica Feurdean ◽  
Andrei-Cosmin Diaconu ◽  
Geanina Butiseaca ◽  
Mariusz Galka ◽  
Simon M. Hutchinson ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Western Siberia ◽  
Fire Regime ◽  
Fire Regimes ◽  
Forest Composition ◽  
Vegetation Composition ◽  
Picea Obovata ◽  
Peatland Hydrology ◽  
In Fire

<p>Boreal forests are among the ecosystems most significantly impacted by wildfires as a consequence of climate warming. A large proportion of the global boreal forest area is located in Siberia, however, its vast extent and restricted access limit datasets recording changes in wildfire activity, especially from a longer-term perspective. Such long-term records of wildfire activity are vital to understanding how fire regimes vary with changes in climate, vegetation composition and human-vegetation interaction, as well as the impacts of wildfires on boreal forests.</p><p>Here, we explore how patterns in fire regime (biomass burned, fire frequency, fire type) have changed over the Holocene. We focus on the relationship between fire regime, forest density and the fire-related traits of the main tree species, and peatland hydrology. We used charcoal-morphologies based reconstructions of fire regimes, along with pollen-based assessments of vegetation composition and testate amoebae-based hydro-climate reconstructions in Pinus-Betula dominated peatlands from central-western Siberia, Tomsk Oblast, Russia.</p><p>The occurrence of more severe fires (i.e., higher biomass burning per fire episode and abundant woody morphotypes) were recorded between 7500 and 5000 cal yr BP. Higher temperatures during that time, likely enhanced peatland dryness and fuel flammability creating conditions conducive to peat and forest fires. Drier peatland conditions also affected forest composition and density by favouring the expansion of a mix of light taiga and fire resisters (e.g., Pinus sylvestris, P. sibirica, Larix) with denser taiga and fire avoiders (Picea obovata and Abies sibirica) on the peatland. A shift to the lowest biomass burning and fire types affecting mostly litter and understorey vegetation, was registered between 4000 and 1500 cal yr BP. Temporally, it coincides with an increase in peatland surface moisture and a change in forest composition characterised by a decline in fire resisters, while fire avoiders remained abundant. An almost synchronous intensification in fires frequency and severity from ca. 2000 cal yr BP to the present at all sites, was concurrent with the rise to dominance of fire-invader species (Betula), as well as a more abundant biomass in the understory layer (shrubs, herbs, ferns, moss), while fire resisters and avoiders declined substantially. We found that Picea obovata to be highly vulnerable tree taxa to frequent, severe fires.</p><p>This long-term perspective demonstratesthat peatland hydrology is connected to, and feedbacks on peatland and forest composition and fuel dryness and ultimately fire regime. It also shows that more frequent fires of higher severity can lead to compositional or structural changes of forests, if trees cannot reach reproductive ages prior to the next burning events. Future predicted increases in temperatures are likely to enhance peatland drying, with cascading effects on forest and peat plant composition, subsequently exacerbating wildfire activity. This study thus contributes to an understanding of disturbance regimes in boreal forests and considers their potential to adapt to new climate conditions and fire regimes.</p><p> </p>

scholarly journals Change of fire frequency in the eastern Canadian boreal forests during the Holocene: does vegetation composition or climate trigger the fire regime?

2001 ◽  
Vol 89 (6) ◽  
pp. 930-946 ◽  
Author(s):  
Christopher Carcaillet ◽  
Yves Bergeron ◽  
Pierre J. H. Richard ◽  
Bianca Fréchette ◽  
Sylvie Gauthier ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Fire Regime ◽  
Fire Frequency ◽  
Vegetation Composition ◽  
The Holocene

scholarly journals How Initial Forest Cover, Site Characteristics and Fire Severity Drive the Dynamics of the Southern Boreal Forest

2020 ◽  
Vol 12 (23) ◽  
pp. 3957
Author(s):  
Victor Danneyrolles ◽  
Osvaldo Valeria ◽  
Ibrahim Djerboua ◽  
Sylvie Gauthier ◽  
Yves Bergeron
Keyword(s):  
Boreal Forest ◽  
Forest Fires ◽  
Forest Dynamics ◽  
Boreal Forests ◽  
Forest Cover ◽  
Fire Severity ◽  
Fire Frequency ◽  
Aerial Photographs ◽  
Forest Composition ◽  
Site Characteristics

Forest fires are a key driver of boreal landscape dynamics and are expected to increase with climate change in the coming decades. A profound understanding of the effects of fire upon boreal forest dynamics is thus critically needed for our ability to manage these ecosystems and conserve their services. In the present study, we investigate the long-term post-fire forest dynamics in the southern boreal forests of western Quebec using historical aerial photographs from the 1930s, alongside with modern aerial photographs from the 1990s. We quantify the changes in forest cover classes (i.e., conifers, mixed and broadleaved) for 16 study sites that were burned between 1940 and 1970. We then analyzed how interactions between pre-fire forest composition, site characteristics and a fire severity weather index (FSWI) affected the probability of changes in forest cover. In the 1930s, half of the cover of sampled sites were coniferous while the other half were broadleaved or mixed. Between the 1930s and the 1990s, 41% of the areas maintained their initial cover while 59% changed. The lowest probability of changes was found with initial coniferous cover and well drained till deposits. Moreover, an important proportion of 1930s broadleaved/mixed cover transitioned to conifers in the 1990s, which was mainly associated with high FSWI and well-drained deposits. Overall, our results highlight a relatively high resistance and resilience of southern boreal coniferous forests to fire, which suggest that future increase in fire frequency may not necessarily result in a drastic loss of conifers.

scholarly journals Multiple air pollutant exposure and lung cancer in Tehran, Iran

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zahra Khorrami ◽  
Mohsen Pourkhosravani ◽  
Maysam Rezapour ◽  
Koorosh Etemad ◽  
Seyed Mahmood Taghavi-Shahri ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Air Pollution ◽  
Cancer Incidence ◽  
Latent Profile Analysis ◽  
Negative Binomial ◽  
Profile Analysis ◽  
Positive Association ◽  
Air Pollutant ◽  
World Health ◽  
Lung Cancer Incidence

AbstractLung cancer is the most rapidly increasing malignancy worldwide with an estimated 2.1 million cancer cases in the latest, 2018 World Health Organization (WHO) report. The objective of this study was to investigate the association of air pollution and lung cancer, in Tehran, Iran. Residential area information of the latest registered lung cancer cases that were diagnosed between 2014 and 2016 (N = 1,850) were inquired from the population-based cancer registry of Tehran. Long-term average exposure to PM10, SO2, NO, NO2, NOX, benzene, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene (BTEX), and BTEX in 22 districts of Tehran were estimated using land use regression models. Latent profile analysis (LPA) was used to generate multi-pollutant exposure profiles. Negative binomial regression analysis was used to examine the association between air pollutants and lung cancer incidence. The districts with higher concentrations for all pollutants were mostly in downtown and around the railway station. Districts with a higher concentration for NOx (IRR = 1.05, for each 10 unit increase in air pollutant), benzene (IRR = 3.86), toluene (IRR = 1.50), ethylbenzene (IRR = 5.16), p-xylene (IRR = 9.41), o-xylene (IRR = 7.93), m-xylene (IRR = 2.63) and TBTEX (IRR = 1.21) were significantly associated with higher lung cancer incidence. Districts with a higher multiple air-pollution profile were also associated with more lung cancer incidence (IRR = 1.01). Our study shows a positive association between air pollution and lung cancer incidence. This association was stronger for, respectively, p-xylene, o-xylene, ethylbenzene, benzene, m-xylene and toluene.

scholarly journals Analysis of Pneumonia Occurrence in Relation to Climate Change in Tanga, Tanzania

2021 ◽  
Vol 18 (9) ◽  
pp. 4731
Author(s):  
Samweli Faraja Miyayo ◽  
Patrick Opiyo Owili ◽  
Miriam Adoyo Muga ◽  
Tang-Huang Lin
Keyword(s):  
Climate Change ◽  
Negative Binomial ◽  
Health Management ◽  
Severe Pneumonia ◽  
Positive Association ◽  
Negative Binomial Regression ◽  
Health Management Information System ◽  
Cold Temperatures ◽  
Climate Indicators ◽  
And Control

In 2018, 70% of global fatalities due to pneumonia occurred in about fifteen countries, with Tanzania being among the top eight countries contributing to these deaths. Environmental and individual factors contributing to these deaths may be multifaceted, but they have not yet been explored in Tanzania. Therefore, in this study, we explore the association between climate change and the occurrence of pneumonia in the Tanga Region, Tanzania. A time series study design was employed using meteorological and health data of the Tanga Region collected from January 2016 to December 2018 from the Tanzania Meteorological Authority and Health Management Information System, respectively. The generalized negative binomial regression technique was used to explore the associations between climate indicators (i.e., precipitation, humidity, and temperature) and the occurrence of pneumonia. There were trend differences in climate indicators and the occurrence of pneumonia between the Tanga and Handeni districts. We found a positive association between humidity and increased rates of non-severe pneumonia (incidence rate ratio (IRR) = 1.01; 95% CI: 1.01–1.02; p ≤ 0.05) and severe pneumonia (IRR = 1.02; 95% CI: 1.01–1.03; p ≤ 0.05). There was also a significant association between cold temperatures and the rate of severe pneumonia in Tanga (IRR = 1.21; 95% CI: 1.11–1.33; p ≤ 0.001). Other factors that were associated with pneumonia included age and district of residence. We found a positive relationship between humidity, temperature, and incidence of pneumonia in the Tanga Region. Policies focusing on prevention and control, as well as promotion strategies relating to climate change-related health effects should be developed and implemented.

Fire regime shift linked to increased forest density in a piñon–juniper savanna landscape

2014 ◽  
Vol 23 (2) ◽  
pp. 234 ◽  
Author(s):  
Ellis Q. Margolis
Keyword(s):  
Regime Shift ◽  
Fire History ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Climatic Conditions ◽  
Tree Density ◽  
High Severity ◽  
Wide Range ◽  
In Fire

Piñon–juniper (PJ) fire regimes are generally characterised as infrequent high-severity. However, PJ ecosystems vary across a large geographic and bio-climatic range and little is known about one of the principal PJ functional types, PJ savannas. It is logical that (1) grass in PJ savannas could support frequent, low-severity fire and (2) exclusion of frequent fire could explain increased tree density in PJ savannas. To assess these hypotheses I used dendroecological methods to reconstruct fire history and forest structure in a PJ-dominated savanna. Evidence of high-severity fire was not observed. From 112 fire-scarred trees I reconstructed 87 fire years (1547–1899). Mean fire interval was 7.8 years for fires recorded at ≥2 sites. Tree establishment was negatively correlated with fire frequency (r=–0.74) and peak PJ establishment was synchronous with dry (unfavourable) conditions and a regime shift (decline) in fire frequency in the late 1800s. The collapse of the grass-fuelled, frequent, surface fire regime in this PJ savanna was likely the primary driver of current high tree density (mean=881treesha–1) that is >600% of the historical estimate. Variability in bio-climatic conditions likely drive variability in fire regimes across the wide range of PJ ecosystems.

Exploiting Poisson additivity to predict fire frequency from maps of fire weather and land cover in boreal forests of Québec, Canada

Ecography ◽  
2016 ◽  
Vol 40 (1) ◽  
pp. 200-209 ◽  
Author(s):  
Jean Marchal ◽  
Steve G. Cumming ◽  
Eliot J. B. McIntire
Keyword(s):  
Land Cover ◽  
Boreal Forests ◽  
Fire Frequency ◽  
Fire Weather

Landscape Eragmentation and Forest Composition Effects on Grouse Breeding Success in Boreal Forests

Ecology ◽  
2000 ◽  
Vol 81 (7) ◽  
pp. 1985 ◽  
Author(s):  
Sami Kurki ◽  
Ari Nikula ◽  
Pekka Helle ◽  
Harto Linden
Keyword(s):  
Breeding Success ◽  
Boreal Forests ◽  
Forest Composition ◽  
Composition Effects

scholarly journals Long-term effects of fire frequency on carbon storage and productivity of boreal forests: a modeling study

2004 ◽  
Vol 24 (7) ◽  
pp. 765-773 ◽  
Author(s):  
J. H. M. Thornley ◽  
M. G. R. Cannell
Keyword(s):  
Carbon Storage ◽  
Boreal Forests ◽  
Fire Frequency ◽  
Long Term Effects ◽  
Modeling Study
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