Winter Fire Research Articles

Impact of Uncontrolled, Rapid Winter Fire in Extensive Grassland

Impact of Uncontrolled, Rapid Winter Fire in Extensive Grassland

A Cold Climate Wooden Home and Conflagration Danger Index: Justification and Practicability for Norwegian Conditions

The vast majority of fire-related deaths occur in residential buildings. Until recently, the fire risk for these buildings was only considered through static risk assessments or period-based assessments applying to certain periods of the year, e.g., Christmas holidays. However, for homes with indoor wooden panelling, especially in the ceiling, a dynamic fire danger indicator can be predicted for cold climate regions. Recognising the effect of fuel moisture content (FMC) of indoor wooden panelling on the enclosure fire development allows for the prediction of a wooden home fire danger indicator. In the present study, dry wood fire dynamics are analysed and experimental observations are reported to support in-home wooden panel FMC as a suitable wooden home fire danger indicator. Then, from previous work, the main equation for modelling in-home FMC is considered and a generic enclosure for FMC modelling is justified based on literature data and supported through a sensitivity study for Norwegian wooden homes. Further, ten years of weather data for three selected locations in Norway, i.e., a coastal town, an inland fjord town and a mountain town, were analysed using a three-dimensional risk matrix to assess the usability of the fire risk modelling results. Finally, a cold climate wooden home fire danger index was introduced to demonstrate how the risk concept can be communicated in an intuitive way using similar gradings as the existing national forest fire index. Based on the generic enclosure, the findings support FMC as a fire risk indicator for homes with interior wooden panelling (walls and ceiling). Large differences in the number of days with arid in-home conditions were identified for the selected towns. The number of days with combined strong wind and dry wooden homes appears to depend more on the number of days with strong wind than days of in-home drought. Thus, the coastal town was more susceptible to conflagrations than the drier inland towns. This aligns well with the most significant fire disasters in Norway since 1900. In addition, it was demonstrated that the number of high-risk periods is manageable and can be addressed by local fire departments through proactive measures. In turn, the fire risk modelling and associated index respond well to the recent changes in Norwegian regulations, requiring the fire departments to have systems for detecting increased risk levels. Testing the modelling for a severe winter fire in the USA indicates that the presented approach may be of value elsewhere as well.

Oncolyic Virotherapy for Prostate Cancer: Lighting a Fire in Winter.

As the most common cancer of the genitourinary system, prostate cancer (PCa) is a global men′s health problem whose treatments are an urgent research issue. Treatment options for PCa include active surveillance (AS), surgery, endocrine therapy, chemotherapy, radiation therapy, immunotherapy, etc. However, as the cancer progresses, the effectiveness of treatment options gradually decreases, especially in metastatic castration-resistant prostate cancer (mCRPC), for which there are fewer therapeutic options and which have a shorter survival period and worse prognosis. For this reason, oncolytic viral therapy (PV), with its exceptional properties of selective tumor killing, relatively good safety in humans, and potential for transgenic delivery, has attracted increasing attention as a new form of anti-tumor strategy for PCa. There is growing evidence that OV not only kills tumor cells directly by lysis but can also activate anticancer immunity by acting on the tumor microenvironment (TME), thereby preventing tumor growth. In fact, evidence of the efficacy of this strategy has been observed since the late 19th century. However, subsequently, interest waned. The renewed interest in this therapy was due to advances in biotechnological methods and innovations at the end of the 20th century, which was also the beginning of PCa therapy with OV. Moreover, in combination with chemotherapy, radiotherapy, gene therapy or immunotherapy, OV viruses can have a wide range of applications and can provide an effective therapeutic result in the treatment of PCa.

Is Portugal Starting to Burn All Year Long? The Transboundary Fire in January 2022

Changes in the large fire seasons induced by climate variability may have implications in several sectors of modern society. This communication aims to investigate possible changes in the behaviour of active fires during the wintertime and document an event that occurred in the transboundary mountainous region in the north-western Iberian Peninsula between Portugal and Spain on 28 January 2022. The VIIRS active fire data, a satellite product, were analysed for the period between December 2012 and February 2022. The Meso-NH model was used to explore the atmospheric conditions during the event that burned almost 2400 ha. It was configured in a single domain with a horizontal resolution of 1500 m (300 × 300 grid points). The study highlights an increase in fire occurrence during the winter of 2021/22 and indicates that climate variability may create atmospheric conditions propitious for fire development even during the winter. The mild temperatures, dry air, and easterly flow affecting northern Portugal played an important role in the fire that occurred on 28 January 2022. Local orographic effects associated with downslope flow favoured fire propagation. Given the lack of knowledge about large winter fires, this study can be a starting point for future research on this subject.

The threat of an indigenous medicinal plant encroacher: Artemisia afra in Klipriviersberg Nature Reserve, Johannesburg, South Africa

AbstractArtemisia afra was identified as an encroaching shrub in the Klipriviersberg Nature Reserve (KNR). Ecological factors that influence the encroachment of A. afra and its population structure were unknown, making it difficult to monitor and control the spread of the plant. This study assessed the density and size‐class distributions (SCD) of A. afra across the main habitats in the KNR (streamside, plains and ridges, with ridges divided into crest, mid‐slope and bottom slope), as well as the relationship between A. afra density and certain ecological factors. Results showed that there was a significant difference (p < 0.05) between plant density on the different habitats with the ridge and bottom slope having by far the highest density (>900 plants/ha). Canopy volume was considered the best measure for the SCD of A. afra. Overall, the population structure of A. afra displayed an inverse J‐shaped curve, indicating that despite clearing efforts and the drought of 2015–2016, it is effectively a recruiting population. Over 71% of the A. afra population were flowering, suggesting relatively rapid attainment of reproductive maturity, and high seed production. Hence, the high levels of encroachment are likely to continue. Further research on controlling A. afra with the integrated use of more intense winter fires, herbicides and the feasibility of sustainable harvesting of this medicinal plant should be undertaken. We also need a much better understanding of the regeneration ecology of A. afra in order to better control it.

Pyric‐based restoration of C4 grasses in woody (Prosopis glandulosa) encroached grassland is best with an alternating seasonal fire regime

Prescribed fire is a management strategy for limiting or reducing woody plant invasion on grasslands and savannas. However, in dense mature woody stands several fires may be necessary to overcome woody dominance and facilitate grassland restoration. Here we determined if a concentrated series of fires could stimulate recovery of C4 perennial grasses in Southern Great Plains, U.S.A., grasslands that had become dominated by a fire tolerant woody legume, honey mesquite (Prosopis glandulosa). Our study included six treatments: three winter fires in 5 years (3WF), three alternating season winter‐summer‐winter fires in 4 years (3AF), three alternating season fires in a more compressed (extreme) timeframe (3AFX), two summer fires in 3 years (2SF), two summer fires in consecutive years (2SFX), and a no fire “Control.” Cattle grazing was excluded during the study. Treatments with summer fire were most effective at top‐killing mesquite, but no treatments root‐killed >5%. All top‐killed mesquite resprouted. Only the treatments that alternated fire seasons (3AF and 3AFX) increased C4 mid‐grass cover, most from stoloniferous vine mesquite (Panicum obtusum) and not C4 bunchgrasses. The 2SF treatment increased C4 short‐grass cover but not C4 mid‐grass cover. Because none of the treatments root‐killed mesquite, grass recovery declined as woody regrowth increased. Drought also contributed to the decline. Without additional fire disturbances to suppress mesquite regrowth or anthropogenic inputs to root‐kill mesquite, transition from woodland to savanna or grassland stable states was not possible.

Eastern Red Bat Responses to Fire during Winter Torpor

Prescribed fires are a forest management tool used to improve natural areas for a variety of benefits including increased plant diversity, reduced competition for desired species, decreased fuel loads, and improved wildlife habitat. The post-fire results in landscapes have shown positive benefits for bat populations. However, prescribed fires set in the winter may cause direct mortality of eastern red bat (Lasiurus borealis) populations that use leaf litter for roosting during periods of colder (<10 °C) temperatures. Therefore, we used controlled laboratory techniques to explore if eastern red bats arouse from torpor when exposed to cues associated with fire (i.e., smoke and the sound of fire). Through subsequent field trials, we confirmed latencies of first response (i.e., movement or increased respiration), arousal, and flight behaviors to the stimuli of fire. We provide evidence of smoke influencing eastern red bat first response and arousal through laboratory and field trial results. Latencies of all behaviors were negatively correlated with temperatures and wind speeds prior to and during field trials. We recommend prescribing winter fires on days when temperatures are >10 °C to provide eastern red bats with a better chance to passively rewarm and react to an approaching fire.

The effect of disturbance and drought on Hairy Jointgrass (Arthraxon hispidus) in north coast New South Wales: Understanding threatened species populations in a dynamic landscape

AbstractEcological disturbances such as fire, grazing or mechanical cultivation can promote or suppress plant populations within vegetation communities. Therefore, such processes can threaten vulnerable species, or play a significant role in their conservation, so an understanding of a species’ ecological response to disturbance is foundational to threatened species management. Various types of anthropogenic disturbance are listed as threats to the vulnerable‐listed Arthraxon hispidus (Hairy Jointgrass) (Poaceae) in NSW; however, there is evidence that slashing, grazing and fire can stimulate the recruitment and establishment of this annual species in some circumstances. We undertook field experiments to investigate the effects of each of these disturbance regimes on A. hispidus populations over two growing seasons within modified wetlands/moist pastures in north coast NSW. We found that the application of fire in winter had a stronger promotional effect on A. hispidus recruitment than slashing, though both treatments increased its abundance and reduced the height and cover of surrounding vegetation, particularly exotic perennial grasses. Following initial establishment, A. hispidus declined under drought conditions during the study, and continuous grazing exacerbated this effect. Drought also increased the abundance of introduced species relative to native wetland species across the study sites. Results confirm that disturbance, particularly fire, can promote A. hispidus populations in some vegetation communities; however, climatic variation also plays a role in its population dynamics. Consideration of each of these factors and their potential interactions is important when developing conservation approaches for this threatened species.

Complementing daily fire-danger assessment using a novel metric based on burnt area ranking

Understanding the relationship between fire and weather has important implications for fire danger evaluations, firefighting and fire management. Fire weather indices are mathematical representations of a suite of meteorological variables that are often used as decision-support tools for evaluating the likelihood of fire on a given day. However, these indices are seldom evaluated for their ability to express a probability in terms of final burnt area, which is a very important fire danger component. We propose a new approach for selecting fire weather indices that represent good proxies for both the probability of fire occurrence on a particular day and of the related final burnt area. The novel performance metric was applied to historical data (11 to 31 years) from four European regions with different fire regimes in Switzerland (Canton Ticino) and Italy (Cilento in Campania, Chilivani and Campidano in Sardinia). The results confirm the suitability of the approach for selecting an appropriate fire weather index for a particular region and for providing insight into the regional meteorological control patterns of fire ignition and spread. For three of the six fire regime types analyzed (Campidano, Cilento and winter fire season in Ticino), the prediction power for burnt area of most indices was generally in accordance with estimates of fire ignition risk. For the remaining case studies, fire ignition and burnt area appear to be controlled by different meteorological or non-climatic drivers. In these cases, the selection of the most suitable index should be based on a cutoff that optimizes the two selection criteria according to local needs. From an operational point of view, this novel approach that includes the burnt area aspect can strongly support decisions on firefighting alert and preparedness as well as requested firefighting strategies.

Forb Cover Increases After Solarization and Winter Fire in a Grassland Invaded by Yellow Bluestem

Solarization (covering soil and vegetation with plastic) has long been used in agriculture to control undesirable plants, but solarization of invasive plants in rangelands has shown mixed and species-specific results. Yellow bluestem (Bothriochloa ischaemum (L.) Keng var. songarica (Rupr. ex Fisch & C.A. Mey) Celarier & Harlan), an invasive perennial C4 grass, is common throughout the southern Great Plains and is not controlled by winter prescribed fire. We tested whether solarization (tarping) with black plastic, combined with winter prescribed fire, could control yellow bluestem. We applied three treatments (with four replicates): solarization (August to November 2017) + fire (January 2018), trimming + fire, and fire only. Results after two growing seasons show that total yellow bluestem cover in solarized + fire plots was reduced to 54% ± 10% (mean ± standard error), lower than trimmed + fire (82% ± 5%, p < 0.01) and fire only plots (78% ± 6%, p = 0.01). Forb cover in solarized + fire plots (15% ± 4%) was much higher than trimmed + fire (4% ± 1%, p < 0.01) and fire only plots (3% ± 1%, p < 0.01). Native forb richness was only slightly higher in solarized + fire plots (16 ± 2 species) compared to fire only (10 ± 2 species, p = 0.08) and trimmed + fire plots (10 ± 1 species, p = 0.08). Interestingly, native forb richness in all plots increased compared to pre-treatment values (2 ± 1 species for all treatments, p < 0.01). Solarization + winter fire can slightly decrease yellow bluestem cover and greatly increase native forb cover, creating islands of diversity in otherwise low-diversity grasslands. However, repeated treatments or alternative techniques will be needed for full control of yellow bluestem.

Fire regime dynamics in mainland Spain. Part 1: Drivers of change

Fire regimes are evolving worldwide driven by socioeconomic and environmental changes. Understanding the forces behind fire regime dynamics is essential to achieve effective wildfire management and policymaking. The current research belongs to a series of two manuscripts aimed at describing spatial-temporal dynamics of fire regime and its drivers in mainland Spain. In this work, we identified the main transitional pathways of fire regime zones between past (1974–1994) and current (1995–2015) conditions to identify the influence of the main wildfire drivers (demographic potential, climate trends, forest interfaces and topography). Our methodology combined Principal Component Analysis and Ward's hierarchical clustering to identify and spatialize homogenous regions of fire regime on the basis of the main fire regime features: number of fires, burned area, burnt area from lightning-caused fires, area affected by large fires (>100 ha) and seasonality. This procedure was replicated in current and past conditions to extract the most frequent combinations of fire regime typologies, eventually leading to a set of binary response variables (change versus persistence of fire regime). Finally, Random Forest regression was applied to estimate the explanatory performance of fire regime drivers for each transition path.Our results point to an overall decline in fire activity over most of the Spanish territory. The hinterlands and Mediterranean coast experienced the greatest decrease in fire activity. In contrast, winter activity has progressed in the North-western region. According to Random Forest outputs, demographic potential highlights as the main driver of fire regime change (both regressive and progressive), followed by climate dynamics (temperature and rainfall trends) and topographic features. In turn, Wildland-Agricultural Interface (WAI) and Wildland-Urban Interface (WUI) were also behind several noticeable trajectories as is the case of winter fire progression (WAI) or moderate increase in fire incidence linked to human-caused fires (WUI).

Fire regime dynamics in mainland Spain. Part 2: A near-future prospective of fire activity

The current research belongs to a series of two manuscripts aiming at describing spatial-temporal dynamics of fire regime and its drivers in Spain. In this work, we present the first attempt to produce a spatial-temporal delimitation of homogeneous fire regime zones in Spain providing insights into the near future. The analyses were based on historical fire records; leveraging autoregressive models to project fire features into the near future. We evaluated the spatial extent of homogenous fire regime zones in three different periods: past (1974–1994), current (1995–2015) and future (2016–2036). To do so, we applied Principal Component Analysis and Ward's hierarchical clustering to identify zones of fire regime on the basis of the spatial and temporal arrangement of their main fire features: number of fires, burned area, burnt area from natural-caused fires, incidence of large fires (> 100 ha) and seasonality. Clusters of fire regime were trained in the current period, being later projected into the past and future periods using of k-Nearest Neighbor classification.ARIMA modeling forecasted a shrinkage in all fire features except natural-caused fires that remained stable. Overall, we detected a transition from significant fire incidence in the past towards a situation with moderate impact of fires in the near future. The Mediterranean coast experienced the largest decline in fire activity with few locations maintaining the historical levels of occurrence of large fires. On the other hand, the Northwestern end of Spain depicted a progression towards winter fire activity while still linked to large fires. This pattern persisted in the near future along the northern coast, whereas an intermix of minor fire progression and regression was expected thorough the hinterlands and the Mediterranean.

Spatial stratification of wildfire drivers towards enhanced definition of large-fire regime zoning and fire seasons

The area affected by wildfires is experiencing an overall decrease in the Mediterranean European region. However, there is no clear trend associated to the incidence of large fire events, which continue to pose an important threat to assets-at-risk, while debates on control by meteorological or fuel drivers are ongoing. Understanding the underlying spatial and temporal patterns of large-fire drivers is of critical importance for a more efficient and science-based management, and specifically for improving wildfire season definition and informing fuel management.Taking advantage of the reliable wildfire data available in Spain, we analyzed large fires (>100 ha) in the period 2010–2015 to outline homogenous spatial-temporal regions in terms of the influence of the main drivers of large-fire activity: temperature, wind speed, slope, distance to populated places and roads, and proximity to agricultural lands. We combined Geographically Weighted Logit Regression (GWLR) models to parameterize the marginal influence of the drivers, with optimized hierarchical clustering to define uniform regions in terms of the underlying driving factors. These regions were subsequently analyzed for monthly distribution of fire occurrence and associated fuel models.We identified four different zones in terms of drivers' features, capturing dissimilar intra-annual patterns of fire activity and affected fuels: one covering the Mediterranean and two along the northern coast, and a fourth aggregation in the hinterlands that seems to act as transition area. The Mediterranean and hinterland were linked to weather-related summer ignitions, late and early summer respectively. The northern cluster gathers most winter fires starting in remote locations under steep slopes and strong wind conditions. The northwestern cluster accounts for most of the fire activity in Spain, related to complex relief and shrub-type fuels.

The importance of fire season when managing threatened plant species: A long-term case-study of a rare Leucopogon species (Ericaceae)

Implemented burns are a primary source of fire in natural systems and occur outside of the wildfire season. However, the impacts of fire season shift on native plant species are rarely studied. Understanding fire season effects are particularly important for managing threatened species, which are often the focus of managed burns. To assess the impacts of fire seasonality and identify potential limiting traits, I studied the threatened Leucopogon exolasius and two common congeners, all of which persist via fire-driven population dynamics. All species were monitored over a 16 year period to assess seedling survival, growth and primary juvenile period after fire. For L. exolasius and the common L. esquamatus, comparisons of survival, growth and maturation were made after winter and summer fires, to assess the effects of season of burn. A key difference was found in primary juvenile period, which was exceptionally long for L. exolasius (>11 years for 80% of the population to flower) compared to the common congeners (3.2–7.57 years). Seasonal seed dormancy mechanisms meant that winter fires delayed emergence, leading to increases in primary juvenile period for both species. A long primary juvenile period may limit L. exolasius population persistence because plants are more likely to be killed by subsequent fire before maturation, while seasonal dormancy cues is a trait that would exacerbate the effects of this interval squeeze. In fire-prone systems, fire frequency is the key factor assumed to drive persistence, however, interactions with fire season can influence recruitment success. There are scant data on recruitment variation in response to fire seasonality, a factor that may have broad implications for rare and common species with seasonal germination requirements.

Modeling anthropogenic and natural fire ignitions in an inner-alpine valley

Abstract. Modeling and assessing the factors that drive forest fire ignitions is critical for fire prevention and sustainable ecosystem management. In southern Europe, the anthropogenic component of wildland fire ignitions is especially relevant. In the Alps, however, the role of fire as a component of disturbance regimes in forest and grassland ecosystems is poorly known. The aim of this work is to model the probability of fire ignition for an Alpine region in Italy using a regional wildfire archive (1995–2009) and MaxEnt modeling. We analyzed separately (i) winter forest fires, (ii) winter fires on grasslands and fallow land, and (iii) summer fires. Predictors were related to morphology, climate, and land use; distance from infrastructures, number of farms, and number of grazing animals were used as proxies for the anthropogenic component. Collinearity among predictors was reduced by a principal component analysis. Regarding ignitions, 30 % occurred in agricultural areas and 24 % in forests. Ignitions peaked in the late winter–early spring. Negligence from agrosilvicultural activities was the main cause of ignition (64 %); lightning accounted for 9 % of causes across the study time frame, but increased from 6 to 10 % between the first and second period of analysis. Models for all groups of fire had a high goodness of fit (AUC 0.90–0.95). Temperature was proportional to the probability of ignition, and precipitation was inversely proportional. Proximity from infrastructures had an effect only on winter fires, while the density of grazing animals had a remarkably different effect on summer (positive correlation) and winter (negative) fires. Implications are discussed regarding climate change, fire regime changes, and silvicultural prevention. Such a spatially explicit approach allows us to carry out spatially targeted fire management strategies and may assist in developing better fire management plans.

Les notations hivernales dans le Moretum: Emprunts virgiliens et intentions parodiques

The author of the Moretum, who is quite unlikely to be identified with Virgil himself, designed a clear winter setting as the background to his narration. An in-depth scrutiny of winter images and topics dispersed throughout the poem (astronomical opening, repeated allusions to the winter fire, description of the farmer's occupations) shows that the poet was a careful reader of the Georgics and borrowed from Virgil's passages related to the winter season. The crafting and tone of several verses confirm the witty and parodic intentions of the author.

Effects of prescribed fire on germination and plant community of Carex cinerascens and Artemisia selengensis in Poyang Lake, China

As an important freshwater lake and wetland area with international significance in biodiversity conservation, Poyang Lake is facing increasing pressure from human activities, including prescribed fire. In the present study, two representative wetland plants from Poyang Lake (Carex cinerascens and Artemisia selengensis) were selected to determine their in situ regeneration success following a prescribed winter fire. Monitoring of plant growth and species composition was carried out monthly for one year following burn treatments. Results showed that significantly higher densities of both C. cinerascens and A. selengensis were observed in the spring. Moreover, the prescribed fire had little influence on the aboveground and belowground biomasses of C. cinerascens, whereas a significant effect on A. selengensis was observed. A smaller difference in dominance values of constructive species was detected between burned and unburned plots. However, a significant increase in biodiversity was found within the burned A. selengensis community in spring. In addition, there was little difference in plant traits and community characters found between burned and unburned plots after the flooding season. Our findings suggest that the water regime is the main driving factor in regulating the ecological process of Poyang Lake, and a single prescribed fire was not sufficient to change the plant community structure, although it did have a significant influence on biomass and species composition in the season following the fire.

Issues and Possible Improvements in Winter Fires Detection by Satellite Radiances Analysis: Lesson Learned in Two Regions of Northern Italy

Lombardy is a region of Northern Italy characterized by an alpine/continental climate, where, in winter, strong dry winds and scarce plants hydration frequently cause surface fires with a relatively low intensity level. In Liguria, a coastal region of Northwestern Italy, climate and vegetation conditions are different from Lombardy; in both winter and summer, severe forest fires frequently occur. This study is based on the investigation of winter fire regimes characterizing the aforementioned regions, using Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) data. In particular, we compare the RST-FIRES and the well-established MOD14/MYD14 fire detection products in order to assess their performance in detecting winter fires in Northern Italy. The study shows as a result that, despite the advantages offered by self-adaptive algorithms like RST-FIRES at local/regional scale, wildfires occurring in Lombardy during the winter season are challenging to identify by satellite. In Liguria region, where morphological and weather conditions favor flame propagation, they seem to be better detectable from space. This study aims at investigating issues affecting satellite monitoring of winter fires by encouraging the usage of a multiplatform observing system, integrating data provided by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) aboard Meteosat Second Generation (MSG) satellites, for better supporting fire management activities.

Seasonal changes in the human alteration of fire regimes beyond the climate forcing

Human activities have altered fire regimes for millennia by suppressing or enhancing natural fire activity. However, whether these anthropogenic pressures on fire activity have exceeded and will surpass climate forcing still remains uncertain. We tested if, how and the extent to which seasonal fire activity in southern France has recently (1976–2009) deviated from climate-expected trends. The latter were simulated using an ensemble of detrended fire–climate models. We found both seasonal and regional contrasts in climatic effects through a mixture of drought-driven and fuel-limited fire regimes. Dry contemporary conditions chiefly drove fire frequency and burned area, although higher fire activity was related to wetter conditions in the last three years. Surprisingly, the relative importance of preceding wet conditions was higher in winter than in summer, illustrating the strong potential dependency of regional fire–climate relationships on the human use and control of fires. In the Mediterranean mountains, warm winters and springs favour extensive fires in the following dry summer. These results highlight that increasing dryness with climate change could have antagonistic effects on fire regime by leading to larger fires in summer (moisture-limited), but lower fire activity in winter (fuel-limited fire regime). Furthermore, fire trends have significantly diverged from climatic expectations, with a strong negative alteration in fire activity in the Mediterranean lowlands and the summer burned area in the mountains. In contrast, alteration of winter fire frequency in the Mediterranean and Temperate mountains has shifted from positive to negative (or null) trends during the mid-1990s, a period when fire suppression policy underwent major revisions. Our findings demonstrate that changes in land-use and fire suppression policy have probably exceeded the strength of climate change effects on changing fire regime in southern Europe, making regional predictions of future fires highly challenging.

Survival and life expectancy of the treeProtea roupelliaesubsp.roupelliaein a montane grassland savanna: Effects of fire regime and plant structure

AbstractSurvival and life expectancy are key demographic determinants of population dynamics. Using data collected in a field experiment monitored over 14 years in montane grassland of the Ukhahlamba‐Drakensberg Park, South Africa, we determined the effects of components of fire regime and plant structure on the survival and life expectancy of the treeProtea roupelliaesubsp.roupelliae(Proteaceae). The field experiment comprised six plots (0.2–0.5 ha in area) from which the survival and life expectancies of 1567 juveniles (non‐reproductives) and 329 adults (reproductives) were estimated in response to differences in fire frequency, biennial seasonal fire, flame height, juvenile height, adult height, basal area and canopy vigour. Juvenile survival and life expectancies were highest when fires were excluded for 8 years. However, a fire after 12 years of fire exclusion and another fire 2 years later eliminated all juveniles. Over the same 14‐year period of biennial fires, juvenile survival was 5%. Juvenile survival and life expectancy were higher after biennial, winter fires than after annual, winter fires. Flame height had no effect on juvenile survival and life expectancy. Both survival and life expectancy of juveniles increased as plants got older and grew taller. Adult survival was unaffected by fire frequency, flame height or tree size, but the survival of adults in response to fire seasonality was inconclusive. Adults with low canopy vigour (&lt;25%) were negatively affected by fire. Juvenile survival and life expectancy are critical bottlenecks in the demography ofP. roupelliae. This species is neither a reseeder nor a resprouter. It avoids lethal fire damage by being restricted to rocky habitats with low fire intensities. Biennial winter fires least threaten the survival and life expectancy ofP. roupelliaeand impact least on its role in the summer feeding and breeding of Gurney's sugarbird.