Linking Forest Fire Regimes and Climate—A Historical Analysis in a Dry Inner Alpine Valley

Forest fire regimes are likely to experience considerable changes in the European Alps due to climatic changes. However, little is known about the recent regional fire history and the impact of local climate on the fire regime during the 20th century. We therefore reconstructed the fire history in a dry continental valley of the Swiss Alps (Valais) over the past 100 years based on documentary evidence, and investigated the relationship between the reconstructed fire regime and the local climatic variability. We compared the impact of temperature, precipitation, drought and dry foehn winds on fire frequency, extent of burnt area, and fire seasonality on various spatial and temporal scales. In the subalpine zone, the fire regime appears to have been mainly driven by temperature and precipitation, whereas these variables seem to have played only a secondary role in the colline–montane zones. Here, foehn winds and, probably, non-climatic factors seem to have been more important. Temperature and precipitation played a major role in shaping fire frequency and burnt area in the first half of the 20th century, but lost their importance during the second half. Our case study illustrates the occurrence of different fire regime patterns and their driving forces on small spatial scales (a few hundred square kilometers). We conclude that the strong rise in temperature over the past century has not profoundly changed the fire regime in Valais, but in the second half of the 20th century temperature was no longer a strong determinant for forest fires as compared to human activities or biomass availability in forests. Author contributions: T.Z., H.B., M.C., and M.B. conceived of or designed study; T.Z. performed research and analyzed data; T.Z., H.B., M.C., and M.B. wrote the paper.     

Changing growth response to wildfire in old‐growth ponderosa pine trees in montane forests of north central Idaho

North American fire‐adapted forests are experiencing changes in fire frequency and climate. These novel conditions may alter postwildfire responses of fire‐adapted trees that survive fires, a topic that has received little attention. Historical, frequent, low‐intensity wildfire in many fire‐adapted forests is generally thought to have a positive effect on the growth and vigor of trees that survive fires. Whether such positive effects can persist under current and future climate conditions is not known. Here, we evaluate long‐term responses to recurrent 20th‐century fires in ponderosa pine, a fire‐adapted tree species, in unlogged forests in north central Idaho. We also examine short‐term responses to individual 20th‐century fires and evaluate whether these responses have changed over time and whether potential variability relates to climate variables and time since last fire. Growth responses were assessed by comparing tree‐ring measurements from trees in stands burned repeatedly during the 20th century at roughly the historical fire frequency with trees in paired control stands that had not burned for at least 70 years. Contrary to expectations, only one site showed significant increases in long‐term growth responses in burned stands compared with control stands. Short‐term responses showed a trend of increasing negative effects of wildfire (reduced diameter growth in the burned stand compared with the control stand) in recent years that had drier winters and springs. There was no effect of time since the previous fire on growth responses to fire. The possible relationships of novel climate conditions with negative tree growth responses in trees that survive fire are discussed. A trend of negative growth responses to wildfire in old‐growth forests could have important ramifications for forest productivity and carbon balance under future climate scenarios.     

Modeling forest fire risk based on GIS-based analytical hierarchy process and statistical analysis in Mediterranean region

This study proposed an integrated approach to generating a forest fire risk map. It used geographic information system–based multiple criteria decision analysis (GIS-MCDA) with the analytic hierarchy process (AHP) and a statistical index (SI). The research was carried out at the Mersin Regional Directorate of Forestry (RDF) in the eastern Mediterranean region of Turkey. Four main criteria, the forest structure, topography, environment, and climate, and 16 subcriteria were used to create the fire risk map. The weight of each criterion was determined using the AHP. The AHP model revealed that environmental factors are the most influential in igniting forest fires, followed by the forest structure. In order to evaluate the results, 990 historical forest fire ignition points were obtained from the Mersin RDF. According to the forest fire risk map, more than 85% of the ignition points were in areas classified as having an extreme or high risk for forest fires. The findings show that the study area is highly prone to forest fires. The relative operating characteristic curve and area under the curve were used to validate the accuracy of the fire risk map. This validation revealed a very high accuracy of 0.775 for the AHP model, indicating a high accuracy in forest fire risk mapping, and the map produced was consistent and reliable. The AHP model and its results will assist decision makers in taking necessary precautions to prevent forest fires and to minimize fire damage, particularly in the eastern Mediterranean region.     

Climate change, human land use and future fires in the Amazon

There is increasing consensus that the global climate will continue to warm over the next century. The biodiversity-rich Amazon forest is a region of growing concern because many global climate model (GCM) scenarios of climate change forecast reduced precipitation and, in some cases, coupled vegetation models predict dieback of the forest. To date, fires have generally been spatially co-located with road networks and associated human land use because almost all fires in this region are anthropogenic in origin. Climate change, if severe enough, could alter this situation, potentially changing the fire regime to one of increased fire frequency and severity for vast portions of the Amazon forest. High moisture contents and dense canopies have historically made Amazonian forests extremely resistant to fire spread. Climate will affect the fire situation in the Amazon directly, through changes in temperature and precipitation, and indirectly, through climate-forced changes in vegetation composition and structure. The frequency of drought will be a prime determinant of both how often forest fires occur and how extensive they become. Fire risk management needs to take into account landscape configuration, land cover types and forest disturbance history as well as climate and weather. Maintaining large blocks of unsettled forest is critical for managing landscape level fire in the Amazon. The Amazon has resisted previous climate changes and should adapt to future climates as well if landscapes can be managed to maintain natural fire regimes in the majority of forest remnants.     

Mediterranean forest dynamics and forest bird distribution changes in the late 20th century

Processes derived from global change such as land-use changes, climate warming or modifications in the perturbation regime may have opposite effects on forest extent and structure with still unknown consequences on forest biodiversity at large spatial scales. In the present study, we aimed at determining forest dynamics associated with global change processes (forest spread, maturation and fire) that have driven the variation in forest bird distributions in Mediterranean forest ecosystems in recent years. The study was located in Catalonia (NE Spain) and used changes in richness of specialist and generalist forest bird species in the last 20 years of the 20th century as indicators of forest biodiversity change. Forest bird distribution changes showed strong spatial patterns and appeared to be related to population processes occurring beyond sampling units (10 km × 10 km squares). Forest maturation appeared as the most important driver of such changes because most of the studied species have a non-Mediterranean origin and are associated with more mature forests. To a lower degree, forest spread also contributed to forest bird distribution changes whereas the impact of forest fires was not associated to a decrease in the richness of either group of forest species. Given the relatively coarse scale at which our study was conducted, caution should be taken when extrapolating our results to the possible future impacts of climate change on fire regime and forest bird distribution. Our results indicate that large-scale forest maturation and spread due mainly to land abandonment in Catalonia has overridden the potentially negative effects of fires on forest bird distributions and are currently driving changes in forest biodiversity patterns across the region.     

Human influences superseded climate to disrupt the 20th century fire regime in Jasper National Park,Canada

To enhance understanding of how climate and humans influenced historical fire occurrence in the montane forests of Jasper National Park, we crossdated fire-scar and tree age samples from 172 plots. We tested effects of drought and climatic variation driven by the El Niño-Southern Oscillation (ENSO) and Pacific North American (PNA) pattern on fire occurrence. We also tested whether local droughts were associated with ENSO, PNA, Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation. We used a combination of instrumental and proxy-climate records to test whether climatic variation explained the absence of fire scars in our study area during the 20th century. From 1646 to 1915, 18 fires burned mainly during drier than average years. Drought years, but not fire years, were associated with positive ENSO and PNA indices, corresponding to warmer conditions with reduced snowpacks. Fire frequency varied through time, although no fire scars have formed since 1915. Potential recording trees present at all plots and climate conducive to fire over multiple years provide evidence that human influences superseded climatic variation to explain the lack of fire scars during the 20th century. Fire suppression significantly altered the fire regime after the formation of Jasper National Park, justifying the ongoing mechanical fuel treatments, prescribed and managed wildfires to improve forest resilience to climate change.     

Simulating vegetation shifts in north-eastern Mediterranean mountain forests under climatic change scenarios

Aim  To explore potential shifts in vegetation and fire regime in some dominant forest types in the north-eastern part of the Mediterranean basin under climate change.
Location  Two altitudinal gradients in the continental part of Greece.
Methods  We developed a forest gap dynamics simulator that provides feedback from the stand to its water balance and flammability status. The model is used to simulate vegetation dynamics in two mountainous areas, currently found under different aridity conditions. Two climatic change scenarios (Intergovernmental Panel on Climate Change A1 and B2) were applied to explore differences in the response of the established forest types. In addition we explicitly accounted for the role of fire, under both current and altered climate patterns.
Results  Fire was identified to play a significant role in low-altitude sites. Its significance increased with the severity of the climate change scenario. Elevational shifts of the dominant species were simulated for each site, while in some cases these changes were associated with a shorter fire cycle and a frequent resetting of processes of vegetation change.
Main conclusions  Our simulations suggest a greater vulnerability of mountainous Mediterranean drier areas regarding compositional alteration and flammability trends. Changes in vegetation could take place through both a discrete and synergistic realization of changes in the drought stress and fire frequency.     

Post‐fire succession and 20th century reduction in fire frequency on xeric southern Appalachian sites

Abstract. We document post‐fire succession on xeric sites in the southern Appalachian Mountains, USA and assess effects of 20th century reduction in fire frequency on vegetation structure and composition. Successional studies over 18 yr on permanent plots that had burned in 1976–1977 indicate that tree mortality and vegetation response varied with fuel load and fire season. In the first three years after fire, hardwood sprouts dominated tree regeneration. On sites where summer and autumn fires reduced litter depth to less than 1 cm, densities of shade‐intolerant Pinus seedlings increased steadily over this period. 4 to 8 yr after fire, large numbers of newly established seedlings and sprouts had grown to 1 – 10 cm DBH. By year 18 growth of these saplings led to canopy closure on most sites. Herbaceous cover and richness peaked in the first decade after fire, then declined. On similar sites that had not burned in more than 50 yr, regeneration of shade‐intolerant Pinus spp. and mean cover and richness of herbs were considerably lower than those observed on recently burned plots. Reconstructions of landscape conditions based on observed post‐fire succession and 20th century changes in fire regime suggest that reductions in fire frequency circa 1940 led to substantial changes in forest structure and decreases in cover and richness of herbaceous species.     

Climatic influences on fire regimes in the northern Sierra Nevada mountains, Lake Tahoe Basin, Nevada, USA

Aim The goal of this study was to understand better the role of interannual and interdecadal climatic variation on local pre‐EuroAmerican settlement fire regimes in fire‐prone Jeffrey pine (Pinus jeffreyi Grev. & Balf.) dominated forests in the northern Sierra Nevada Mountains. Location Our study was conducted in a 6000‐ha area of contiguous mixed Jeffrey pine‐white fir (Abies concolor Gordon & Glend.) forest on the western slope of the Carson Range on the eastern shore of Lake Tahoe, Nevada. Methods Pre‐EuroAmerican settlement fire regimes (i.e. frequency, return interval, extent, season) were reconstructed in eight contiguous watersheds for a 200‐year period (1650–1850) from fire scars preserved in the annual growth rings of nineteenth century cut stumps and recently dead pre‐settlement Jeffrey pine trees. Superposed epoch analysis (SEA) and correlation analysis were used to examine relationships between tree ring‐based reconstructions of the Palmer Drought Severity Index (PDSI), Southern Oscillation Index (SOI), Pacific Decadal Oscillation (PDO) and pre‐EuroAmerican fire regimes in order to assess the influence of drought and equatorial and north Pacific teleconnections on fire occurrence and fire extent. Results For the entire period of record (1650–1850), wet conditions were characteristic of years without fires. In contrast, fire years were associated with drought. Drought intensity also influenced fire extent and the most widespread fires occurred in the driest years. Years with widespread fires were also preceded by wet conditions 3 years before the fire. Widespread fires were also associated with phase changes of the PDO, with the most widespread burns occurring when the phase changed from warm (positive) to cold (negative) conditions. Annual SOI and fire frequency or extent were not associated in our study. At decadal time scales, burning was more widespread during decades that were dryer and characterized by La Niña and negative PDO conditions. Interannual and interdecadal fire–climate relationships were not stable over time. From 1700 to 1775 there was no interannual relationship between drought, PDO, and fire frequency or extent. However, from 1775 to 1850, widespread fires were associated with dry years preceded by wet years. This period also had the strongest association between fire extent and the PDO. In contrast, fire–climate associations at interdecadal time scales were stronger in the earlier period than in the later period. The change from strong interdecadal to strong interannual climate influence was associated with a breakdown in decadal scale constructive relationships between PDO and SOI. Main conclusions Climate strongly influenced pre‐settlement pine forest fire regimes in northern Sierra Nevada. Both interannual and interdecadal climatic variation regulated conditions conducive to fire activity, and longer term changes in fire frequency and extent correspond with climate‐mediated changes observed in both the northern and southern hemispheres. The sensitivity of fire regimes to shifts in modes of climatic variability suggests that climate was a key regulator of pine forest ecosystem structure and dynamics before EuroAmerican settlement. An understanding of pre‐EuroAmerican fire–climate relationships may provide useful insights into how fire activity in contemporary forests may respond to future climatic variation.     

Spatial and temporal variability in fire occurrence within the Las Bayas Forestry Reserve, Durango, Mexico

Patterns of fire occurrence within the Las Bayas Forestry Reserve, Mexico are analyzed in relation to variability in climate, topography, and human land-use. Significantly more fires with shorter fire return intervals occurred from 1900 to 1950 than from 1950 to 2001. However, the frequency of widespread fire years (25% filter) was unchanged over time, as widespread fires were synchronized by climatic extremes. Widespread fire years occurred during dry years that lagged wet years. Widespread fire years lagged the negative El Niño phase (wet winters) of the Southern Oscillation by 1 year, but were not synchronized by the positive, La Niña phase (dry winters) of the Southern Oscillation. The smaller, localized fires that occurred more frequently during the first half of the 20th century were attributed to changes in land tenure with the introduction of the ejido system in the early 1950s. Ejido management strategies lowered fire frequencies by suppressing fires and reducing anthropogenic fires. There were likely more ignitions prior to the arrival of the ejido system as fires were ignited by lightning and indigenous people. As the movement of indigenous peoples across the landscape has been restricted by changes in land tenure, numbers of human-ignited fires subsequently decreased post 1950. After 1950, fires occurred less frequently, were more synchronized, and more restricted to years of extreme climate.     

Climate regime shift and forest loss amplify fire in Amazonian forests

Frequent Amazonian fires over the last decade have raised the alarm about the fate of the Earth's most biodiverse forest. The increased fire frequency has been attributed to altered hydrological cycles. However, observations over the past few decades have demonstrated hydrological changes that may have opposing impacts on fire, including higher basin‐wide precipitation and increased drought frequency and severity. Here, we use multiple satellite observations and climate reanalysis datasets to demonstrate compelling evidence of increased fire susceptibility in response to climate regime shifts across Amazonia. We show that accumulated forest loss since 2000 warmed and dried the lower atmosphere, which reduced moisture recycling and resulted in increased drought extent and severity, and subsequent fire. Extremely dry and wet events accompanied with hot days have been more frequent in Amazonia due to climate shift and forest loss. Simultaneously, intensified water vapor transport from the tropical Pacific and Atlantic increased high‐altitude atmospheric humidity and heavy rainfall events, but those events did not alleviate severe and long‐lasting droughts. Amazonia fire risk is most significant in the southeastern region where tropical savannas undergo long seasonally dry periods. We also find that fires have been expanding through the wet–dry transition season and northward to savanna–forest transition and tropical seasonal forest regions in response to increased forest loss at the “Arc of Deforestation.” Tropical forests, which have adapted to historically moist conditions, are less resilient and easily tip into an alternative state. Our results imply forest conservation and fire protection options to reduce the stress from positive feedback between forest loss, climate change, and fire.     

Impacts of climate change on fire activity and fire management in the circumboreal forest

Forest fires are a significant and natural element of the circumboreal forest. Fire activity is strongly linked to weather, and increased fire activity due to climate change is anticipated or arguably has already occurred. Recent studies suggest a doubling of area burned along with a 50% increase in fire occurrence in parts of the circumboreal by the end of this century. Fire management agencies' ability to cope with these increases in fire activity is limited, as these organizations operate with a narrow margin between success and failure; a disproportionate number of fires may escape initial attack under a warmer climate, resulting in an increase in area burned that will be much greater than the corresponding increase in fire weather severity. There may be only a decade or two before increased fire activity means fire management agencies cannot maintain their current levels of effectiveness.     

A Climate-Based Approach to the Restoration of Fire-Dependent Ecosystems

Recurrent fires are integral to the function of many ecosystems worldwide. The management of fire‐frequented ecosystems requires the application of fire at the appropriate frequency and seasonality, but establishing the natural fire regime for an ecosystem can be problematic. Historical records of fires are often not available, and surrogates for past fires may not exist. We suggest that the relationship between climate and fire can provide an alternative means for inferring past fire regimes in some ecosystems.     

Fire-Mediated Forest Encroachment in Response to Climatic and Land-Use Change in Subtropical Andean Treelines

We used dendroecological techniques to analyze the effects of rainfall and grazing on fire regime and its implications for tree regeneration in subtropical mountains of northwestern Argentina during the 20th century, a period characterized by increasing rainfall and decreasing land-use intensity. We dated fire scars and establishment of Alnus acuminata (the dominant tree species) in six watersheds along a 600 km latitudinal range. We correlated fire frequency with rainfall records and performed Superposed Epoch Analyses to assess the relationship between rainfall and fire events during the century, and in two sub-periods: 1930–1965 (low rainfall, high grazing) and 1966–2001 (high rainfall, low grazing). We performed permutation analyses to assess the association between fire events and tree establishment, and to describe the spatial distribution of fires and forests in relation to hillslope aspect. Rainfall was associated with regional fires at interannual and decadal scales: fire probability increased after growing seasons with above-average rainfall and through the century, in concurrence with rainfall increase. The climatic control of fire was stronger under lower land-use intensity. Tree establishment was temporally associated with fire events, which occurred mainly in north facing slopes, where grassland cover is more extensive and forest colonization more likely. These results suggest that fire is limited by the availability of fine fuels, which is enhanced by high rainfall and reduced grazing; and tree establishment is limited by the competition with grasses. Consequently, increasing rainfall and decreasing grazing favored higher fire frequency, thus promoting forest encroachment during 20th century.     

Recent fire regime characteristics and potential natural vegetation relationships in Spain

Abstract. In heavily altered landscapes, where vegetation is not natural and where people are the main source of ignitions, relationships between fire occurrence and climate conditions may be unclear. The objective of this study was to evaluate to what extent territories with similar Potential Natural Vegetation (PNV) in peninsular Spain differ in their forest fire characteristics. From 1974 to 1994, more than 174 000 fires occurred. We used (1) the Spanish data base of forest fires, (2) a PNV map and (3) a land use map. Separate fire characteristics, based either on the number of fires occurred or the area burned, were obtained for each of the ca. 5000 grid‐cells (10 km × 10 km) into which peninsular Spain is divided in the UTM projection. Also, meteorological conditions at the time of fire ignition, cause of ignition and present forest cover were referred to the same grid‐cells as external factors potentially determinant of fire occurrence. The relationships between fire regime characteristics and PNV units were explored with Principal Components Analysis (PCA). The role of the three sets of external factors in the fire characteristics was evaluated with Redundancy Analysis (RDA). Groups of similar PNV types were clearly segregated, suggesting a gradient of fire characteristics. Higher fire incidence (higher frequencies and spatial incidence of fires, but lower proportions of grid‐cells affected by large fires) was associated with Atlantic, warm territories with deciduous forests as PNV. Intermediate fire frequency and rotation period, but with a higher relative incidence of medium and large fires occurred in Mediterranean PNV units, dominated by sclerophyllous oak forests. Low fire frequency and long rotation periods, with strong seasonal and yearly variability occurred for PNV units in the cold uplands (Fagus, Pinus, Abies, Juniperus) or in the semi‐arid, shrubby PNV units. The cause of ignition best explained the patterns of forest fire characteristics, followed by weather conditions. Our results indicate that, even in human influenced regions, climate and soil conditions exert control on the resulting forest fire characteristics, as indicated by the high segregation of the PNV types. However, the role of man was crucial in shifting the patterns of fire incidence. This was so that highest fire incidence occurred in regions that, otherwise, would be expected to have a much lower one, thus posing a serious threat for such areas. PNV maps, by providing a phytogeographical framework for characterizing forest fires, could be valuable tools for applying research results to forest fire management policies, taking properly into account the underlying determinant factors.     

Spatially explicit fire-climate history of the boreal forest-tundra (Eastern Canada) over the last 2000 years

Across the boreal forest, fire is the main disturbance factor and driver of ecosystem changes. In this study, we reconstructed a long-term, spatially explicit fire history of a forest-tundra region in northeastern Canada. We hypothesized that current occupation of similar topographic and edaphic sites by tundra and forest was the consequence of cumulative regression with time of forest cover due to compounding fire and climate disturbances. All fires were mapped and dated per 100 year intervals over the last 2,000 years using several fire dating techniques. Past fire occurrences and post-fire regeneration at the northern forest limit indicate 70% reduction of forest cover since 1800 yr BP and nearly complete cessation of forest regeneration since 900 yr BP. Regression of forest cover was particularly important between 1500s-1700s and possibly since 900 yr BP. Although fire frequency was very low over the last 100 years, each fire event was followed by drastic removal of spruce cover. Contrary to widespread belief of northward boreal forest expansion due to recent warming, lack of post-fire recovery during the last centuries, in comparison with active tree regeneration more than 1,000 years ago, indicates that the current climate does not favour such expansion.     

Inter-hemispheric synchrony of forest fires and the El Niño-Southern Oscillation

Fire histories were compared between the south-western United States and northern Patagonia, Argentina using both documentary records (1914–87 and 1938–96, respectively) and tree-ring reconstructions over the past several centuries. The two regions share similar fire–climate relationships and similar relationships of climatic anomalies to the El Niño–Southern Oscillation (ENSO). In both regions, El Niño events coincide with above-average cool season precipitation and increased moisture availability to plants during the growing season. Conversely, La Niña events correspond with drought conditions. Monthly patterns of ENSO indicators (southern oscillation indices and tropical Pacific sea surface temperatures) preceding years of exceptionally widespread fires are highly similar in both regions during the 20th century. Major fire years tend to follow the switching from El Niño to La Niña conditions. El Niño conditions enhance the production of fine fuels, which when desiccated by La Niña conditions create conditions for widespread wildfires. Decadal-scale patterns of fire occurrence since the mid-17th century are highly similar in both regions. A period of decreased fire occurrence in both regions from c. 1780–1830 coincides with decreased amplitude and/or frequency of ENSO events. The interhemispheric synchrony of fire regimes in these two distant regions is tentatively interpreted to be a response to decadal-scale changes in ENSO activity. The ENSO–fire relationships of the south-western USA and northern Patagonia document the importance of high-frequency climatic variation to fire hazard. Thus, in addition to long-term trends in mean climatic conditions, multi-decadal scale changes in year-to-year variability need to be considered in assessments of the potential influence of climatic change on fire regimes.     

Dynamics, patterns and causes of fires in Northwestern Amazonia

According to recent studies, two widespread droughts occurred in the Amazon basin, one during 2005 and one during 2010. The drought increased the prevalence of climate-driven fires over most of the basin. Given the importance of human-atmosphere-vegetation interactions in tropical rainforests, these events have generated concerns over the vulnerability of this area to climate change. This paper focuses on one of the wettest areas of the basin, Northwestern Amazonia, where the interactions between the climate and fires are much weaker and where little is known about the anthropogenic drivers of fires. We have assessed the response of fires to climate over a ten-year period, and analysed the socio-economic and demographic determinants of fire occurrence. The patterns of fires and climate and their linkages in Northwestern Amazonia differ from the enhanced fire response to climate variation observed in the rest of Amazonia. The highest number of recorded fires in Northwestern Amazonia occurred in 2004 and 2007, and this did not coincide with the periods of extreme drought experienced in Amazonia in 2005 and 2010. Rather, during those years, Northwestern Amazonia experienced a relatively small numbers of fire hotspots. We have shown that fire occurrence correlated well with deforestation and was determined by anthropogenic drivers, mainly small-scale agriculture, cattle ranching (i.e., pastures) and active agricultural frontiers (including illegal crops). Thus, the particular climatic conditions for air convergence and rainfall created by proximity to the Andes, coupled with the presence of one of the most active colonisation fronts in the region, make this region differently affected by the general drought-induced fire patterns experienced by the rest of the Amazon. Moreover, the results suggest that, even in this wet region, humans are able to modify the frequency of fires and impact these historically well preserved forests.     

Climate change and wildfires in Russia

The effect of climate change on the distribution, intensity, and transforming role of wild fires is considered. A general overview of the current wild fire regimes (WRs) and impacts on forest ecosystems and environment is provided. One distinctive feature of WRs is the increasing frequency of disastrous wild fires. The application of various remote sensing instruments has shown that the average vegetation wild fire area in Russia for 1998–2010 accounted for 8.2 ± 0.8 × 10⁶ ha, with about two-thirds of wildfires occurring on forest lands and half on the forested lands. The average annual fire carbon balance during the above period was 121 ± 28 Tg C yr^?1, including 92 ± 18 Tg C yr^?1 emitted from the forested land. The forecasts based on the General Circulation Models suggest the dramatic acceleration of fire regimes by the end of the 21st century. Taking into account the increase in the dryness of the climate and the thawing of permafrost, this will likely lead to a dramatic loss of forested area and the impoverishment of the forest cover over a major part of the forest zone. A transition to adaptive forestry would allow a substantial decrease of the expected losses. This paper takes a brief look at the general principals of adapting forest fire protection system to climate change, which is considered an integral part of the transition to sustainable forest management in Russia.     

Climate and the inter‐annual variability of fire in southern Africa: a meta‐analysis using long‐term field data and satellite‐derived burnt area data

Aim This study investigates inter‐annual variability in burnt area in southern Africa and the extent to which climate is responsible for this variation. We compare data from long‐term field sites across the region with remotely sensed burnt area data to test whether it is possible to develop a general model. Location Africa south of the equator. Methods Linear mixed effects models were used to determine the effect of rainfall, seasonality and fire weather in driving variation in fire extent between years, and to test whether the effect of these variables changes across the subcontinent and in areas more and less impacted by human activities. Results A simple model including rainfall and seasonality explained 40% of the variance in burnt area between years across 10 different protected areas on the subcontinent, but this model, when applied regionally, indicated that climate had less impact on year‐to‐year variation in burnt area than would be expected. It was possible to demonstrate that the relative importance of rainfall and seasonality changed as one moved from dry to wetter systems, but most noticeable was the reduction in climatically driven variability of fire outside protected areas. Inter‐annual variability is associated with the occurrence of large fires, and large fires are only found in areas with low human impact. Main conclusions This research gives the first data‐driven analysis of fire–climate interactions in southern Africa. The regional analysis shows that human impact on fire regimes is substantial and acts to limit the effect of climate in driving variation between years. This is in contrast to patterns in protected areas, where variation in accumulated rainfall and the length of the dry season influence the annual area burnt. Global models which assume strong links between fire and climate need to be re‐assessed in systems with high human impact.