Macroscopic Charcoal Research Articles

Land use history and resource utilisation from a.d. 400 to the present, at Chibuene, southern Mozambique

This paper discusses changing patterns of resource utilisation over time in the locality of Chibuene, Vilankulos, situated on the coastal plain of southern Mozambique. The macroscopic charcoal, bone and shell assemblages from archaeological excavations are presented and discussed against the off-site palaeoecological records from pollen, fungal spores and microscopic charcoal. The Chibuene landscape has experienced four phases of land use and resource utilisation that have interacted with changes in the environment. Phase 1 (a.d. 400–900), forest savanna mosaic, low intensity cattle herding and cultivation, trade of resources for domestic use. Phase 2 (a.d. 900–1400), forest savanna mosaic, high intensity/extensive cultivation and cattle herding. Phase 3 (a.d. 1400–1800), savanna woodland and progressive decrease in forests owing to droughts. Decline of agricultural activities and higher reliance on marine resources. Possible trade of resources with the interior. Phase 4 (a.d. 1800–1900), open savanna with few forest patches. Warfare and social unrest. Collapse of trade with the interior. Decline in marine resources and wildlife. Loss of cattle herds. Expansion of agriculture locally and introduction of New World crops and clearing of Brachystegia trees. The study shows the importance of combining different environmental resources for elucidating how land use and natural variability have changed over time.

The ancient forests of La Gomera, Canary Islands, and their sensitivity to environmental change

Summary Garajonay National Park in La Gomera (Canary Islands) contains one of the largest remnant areas of a forest formation once widespread throughout Europe and North Africa. Here, we aim to address the long‐term dynamics (the last 9600 cal. years) of the monteverde forest (laurel forest and Morella‐Erica heath) located close to the summit of the National Park (1487 m a.s.l.) and determine past environmental and human impacts. We used palaeoecological (fossil pollen, microscopic and macroscopic charcoal) and multivariate ecological techniques to identify compositional change in the monteverde forest in relation to potential climatic and human influences, based on the analysis of a core site at 1250‐m elevation. The regional mid‐Holocene change towards drier conditions was matched in this system by a fairly rapid shift in representation of key forest elements, with declines in Canarian palm tree (Phoenix canariensis), Canarian willow (Salix canariensis) and certain laurel forest taxa and an increase in representation of the Morella–Erica woody heath. Charcoal data suggest that humans arrived on the island between about 3000 and 1800 years ago, a period of minimal vegetation change. Levels of burning over the last 800 years are among the lowest of the entire 9600 years. Synthesis. A rapid climatic‐induced shift of forest taxa occurred 5500 years ago, with a decrease in hygrophilous species in the pollen record. In contrast, we found no evidence of a significant response to human colonization. These findings support the idea that Garajonay National Park is protecting a truly ancient relict, comprising a largely natural rather than cultural legacy.

2012 Deevey Award to Ryan Kelly

Edward S. Deevey, a founder of modern paleoecology, was a dedicated student advisor who mentored many investigators active in the field of paleoecology today. To honor his memory and to encourage high-quality research by graduate students, the Paleoecology Section presents an award for the best oral or poster presentation by a student in paleoecology at the ESA Annual Meeting. Ryan Kelly, a Ph.D. candidate in the Department of Plant Biology at the University of Illinois, is the winner of the 2012 Deevey award for his presentation: “Pushing the limits of the boreal-forest fire regime: recent changes in a 10,000 year context.” His presentation was coauthored by Melissa Chipman, Philip E. Higuera, Linda B. Brubaker, and Feng Sheng Hu. His research reconstructed 10,000 years of boreal-forest fire history from analysis of macroscopic charcoal accumulation in sediment cores from Alaska. He presented evidence that the boreal fire regime has been changing through fuel depletion. Mr. Kelly completed a Bachelor of Science in Integrative Biology from the University of Illinois in 2005. Ryan Kelly Carolyn Barrett This year the Deevey Committee awarded a second-place prize to Carolyn Barrett, a Ph.D. candidate in the Program in Ecology, Evolution, and Conservation Biology at the University of Illinois, for her presentation: “How many lake sediment cores do we need to characterize regional fire records?” This presentation was co-authored with Feng Sheng Hu. Ms. Barrett conducted a statistical analysis of charcoal accumulation rate (CHAR) records for lakes from two Alaskan ecoregions. Her research focuses on the interactions of landscape, vegetation, and climate in controlling boreal forest fires. The Paleoecology Section thanks students who competed for this year's Deevey Award, and we encourage them and others to participate in the 2013 competition, to be held in Minneapolis, Minnesota.

Palaeobotanical evidence of wildfire in the Upper Permian of India: Macroscopic charcoal remains from the Raniganj Formation, Damodar Basin

Macroscopic fossil charcoal has been discovered in the carbonaceous shales associated with Seam-VI of Raniganj Formation, Upper Permian, Damodar Basin, India. A pycnoxylic gymnosperm wood is described and confirms the occurrence of palaeo-wildfire in this area during the Late Permian. The integration of the data presented in the current study with previously published data for the Raniganj Formation, principally related to the occurrence of (pyrogenic) inertinites within coal layers, demonstrates that palaeo-wildfires were common events during the deposition of the preserved material. In addition, the presence of charcoal in Permian sediments associated with coal levels at different Gondwana localities demonstrates that wildfires have been relatively common events across the continent during this period.

The Age of the Late Mesolithic on the North York Moors, England: radiocarbon dating a small flint tool stratified in peat from East Bilsdale Moor

There has been a considerable amount of pollen-analytical research on the palaeoecology and palaeoenvironment of the Late Mesolithic culture of the North York Moors upland in north-east Yorkshire, which together with the Pennines is the most prolific area in Britain for Late Mesolithic flint sites. The peat sediments of the Moors have provided detailed data on the vegetation history of the mid-Holocene, both natural developments and also woodland disturbance by fire, as revealed in the macroscopic and microscopic charcoal evidence preserved in the peats and in its relation to the recorded changes in woodland composition and density. The Late Mesolithic vegetation history of the North York Moors can now be reconstructed with confidence and, given the high concentration of lithic sites of that period, linkages between the archaeological and palaeoecological records are often attempted with a view to explaining disturbance regimes as resulting from the impacts of foragers’ activities in the landscape. Unlike the Pennines, however, in the North York Moors no Late Mesolithic sites have been radiocarbon dated, so no chronological correlation can be made between the palaeoenvironmental data and the archaeological evidence. This paper presents the first radiocarbon date for a Late Mesolithic flint artefact from the North York Moors, from East Bilsdale Moor, and examines its implications for the age range of the Late Mesolithic on the Moors as a whole, and for the association of evidence of woodland disturbance on the Moors upland with the presence of Late Mesolithic hunters there.

The burning of Gondwana: Permian fires on the southern continent—A palaeobotanical approach

Fossil charcoal has widely been accepted as a direct indicator for the occurrence of palaeo-wildfires. In Upper Palaeozoic sediments of Euramerica and Cathaysia, records of these remains are relatively common and (regionally and stratigraphically) more or less homogeneously distributed in terrestrial sequences. On the other hand, just a few records have been published for the Permian of Gondwana and only recently has it been demonstrated that macroscopic charcoals are also common here. Most Permian macroscopic charcoal from Gondwana is gymnospermous and has been reported from coal-bearing strata. Macroscopic charcoal occurrences are spread out in different sequences and also in distinct stratigraphic intervals in the Permian [e.g., Paraná Basin (Sakmarian/Artinskian of Brazil), Karoo Basin (Artinskian of South Africa), Damodar Basin (Lopingian of India) and Dead Sea area (Changhsingian of Jordan)]. They range from peri-glacial/post-glacial to warm temperate climatic systems throughout the Permian. Macro- and micro-charcoal occurrences are compared to inertinite incidences to support the pyrogenic origin for these coal macerals and to provide an up to date overview on the known evidences of Permian wildfires on Gondwana in space and time.

A 7000-Year Record of Environmental Change, Bear Lake, Rocky Mountain National Park, USA

Few long-term records of the fire history of Rocky Mountain National Park exist. Data from a lake sediment core was used to reconstruct changes in vegetation and fire frequencies over the last 7000 cal yr. Bear Lake is a high-elevation lake surrounded by subalpine vegetation in Rocky Mountain National Park, Colorado. Pollen data indicate that a warm and dry climate prevailed between ca. 7000 and 5000 cal yr BP. Temperatures increased until shortly before ca. 3500 cal yr BP when evidence for a marked decline is seen. Cooler-than-present conditions were maintained until ca. 1700 cal yr BP, when conditions transitioned to more like those of the present-day climate. Based on macroscopic charcoal analyses, fire frequency had varied between two and five episodes per 1000 years. The largest peak in charcoal was at ca. 590 cal yr BP. The fire return interval has varied with climate over time; however, we calculate a fire return interval of 325 years over the past 7000 years. Given these results, fire activity is likely to increase under current Intergovernmental Panel on Climate Change climate projections of an increase in annual temperatures.

Mesozoic (Late Jurassic) palynomorphs and charcoal from a sandstone pebble from Quaternary glacial deposits of the North Sea

The palynological contents as well as macroscopic charcoal fragments from a calcareous sandstone pebble from Quaternary glacial deposits of the North Sea (80 km SW of the Dogger Bank) are described. The taxonomic composition of the palynoflora points to a Late Jurassic (or Late Jurassic/Early Cretaceous) age of the sandstone. The charcoal is interpreted as direct evidence of palaeo‐wildfire occurring during this period in the source area of the sediments of this particular sandstone. This finding, together with already published data on Mesozoic deposits, allows to conclude that wildfires were obviously widespread during this period in the area of the modern day North Sea and adjacent areas. Copyright © 2012 John Wiley & Sons, Ltd.

Late-glacial and Holocene vegetation and climate variability, including major droughts, in the Sky Lakes region of southeastern New York State

Sediment cores from Lakes Minnewaska and Mohonk in the Shawangunk Mountains of southeastern New York were analyzed for pollen, plant macrofossils, macroscopic charcoal, organic carbon content, carbon isotopic composition, carbon/nitrogen ratio, and lithologic changes to determine the vegetation and landscape history of the greater Catskill Mountain region since deglaciation. Pollen stratigraphy generally matches the New England pollen zones identified by Deevey (1939) and Davis (1969), with boreal genera (Picea, Abies) present during the late Pleistocene yielding to a mixed Pinus, Quercus and Tsuga forest in the early Holocene. Lake Minnewaska sediments record the Younger Dryas and possibly the 8.2calkyrBP climatic events in pollen and sediment chemistry along with an ~1400calyr interval of wet conditions (increasing Tsuga and declining Quercus) centered about 6400calyrBP. Both Minnewaska and Mohonk reveal a protracted drought interval in the middle Holocene, ~5700–4100calyrBP, during which Pinus rigida colonized the watershed, lake levels fell, and frequent fires led to enhanced hillslope erosion. Together, the records show at least three wet–dry cycles throughout the Holocene and both similarities and differences to climate records in New England and central New York. Drought intervals raise concerns for water resources in the New York City metropolitan area and may reflect a combination of enhanced La Niña, negative phase NAO, and positive phase PNA climatic patterns and/or northward shifts of storm tracks.

Charcoal Dispersal from Alpine Stallo Hearths in Sub-Arctic Sweden: Patterns Observed from Soil Analysis and Experimental Burning

To evaluate dispersal patterns and concentrations of macroscopic charcoal particles around Stollo settlements in sub-arctic Scandinavia, their distributions following experimental burning and soil concentrations around an alpine Stollo settlement dating between AD 700 and 1150 were recorded. After the burning 98% of recorded particles were 0.1-0.5 mm long, 90% were dispersed within 40 m of the fire, their mean concentration 40 m from the fire was 0.14±0.08 particles/cm2 and the concentration decreased with increasing distance. At the settlement, 95% of recorded charcoal particles were 0.1-0.5 mm long, 94% were within 40 m of the hearths, the mean concentration declined with increasing distance, and concentrations were much lower than expected from the experimental burning (e.g. 17.6±2.4 particles/cm2, 40 m away). In conclusion: biological archives used for charcoal analysis in archaeological and vegetation history studies should be located ?40 m from settlements, and data obtained from charcoal analyses should be interpreted cautiously.

The record of Triassic charcoal and other evidence for palaeo-wildfires: Signal for atmospheric oxygen levels, taphonomic biases or lack of fuel?

As wildfires are today important sources of disturbance in many terrestrial ecosystems, it is of great interest to understand how different environmental parameters and fire-activity interacted during past periods of the Earth history. Fossil charcoal, inertinites, and pyrogenic polycyclic aromatic hydrocarbons (PAHs) represent the only direct evidence for the occurrence of such palaeo-wildfires. In the present study, a review of published data, together with new data on the occurrence of fossil charcoal for the Permian and the Triassic is presented. For a long time, it has been speculated, that an assumed lack of evidence for palaeo-wildfires during the Triassic should be explained by a large drop in atmospheric oxygen concentration following or during the end-Permian mass extinction event, preventing the occurrence of wildfires. However, evidence for palaeo-wildfires is relatively common in many middle and late Triassic strata, whereas such evidence is almost totally lacking from early Triassic sediments. The interpretation of this “charcoal gap” or depression is difficult, as many factors (e.g. atmospheric oxygen concentration, taphonomical biases, lack of sediments suitable for the preservation of macroscopic charcoal, lack of fuel, and “ignorance” of scientists) may have influenced not only the production, but also the preservation and recovery of evidence for palaeo-wildfires during this period. Thus, it is not clear whether this Early Triassic “charcoal gap” can also be seen as evidence for an assumed “wildfire gap” or not. Without any doubt further investigations on the early Triassic record of charcoal and other evidence for palaeo-wildfires will be necessary before this problem can be solved. In fact, it can be expected that the number of published records of (early) Triassic evidence for palaeo-wildfires will increase in the future as more and more scientist working on sediments of this age may become aware of the interest in fires from this time. This will certainly make it possible to give a much better picture of the temporal and regional distribution of wildfires during this period in the future.

Long-term effects of agriculture on soil carbon pools and carbon chemistry along a Hawaiian environmental gradient

Intensive agriculture has the potential to reduce soil carbon stocks in the years following initial cultivation, although the magnitude and direction of the effect can vary with ecosystem and management factors. Agriculture can also shift the carbon chemistry of soils via changes in crop plant chemistry, decomposition, and/or soil amendments [e.g. black carbon (i.e. charcoal)]. It is possible that soil carbon levels can recover if intensive cultivation ends, but the factors driving the extent and quality of this recovery are not well understood. Here, we examined soil carbon pool sizes and carbon chemistry >200 years after intensive cultivation by early Hawaiians. We compared soils from an extensive pre-European-contact agricultural field system with reference sites under similar modern management. Sites were selected along a climate and soil weathering gradient to investigate interactions between historic land use and ecosystem properties, such as soil mineralogy, in driving soil carbon recovery. Soil carbon content was measured from 0 to 30 cm depth, and carbon chemistry was assessed using 13C nuclear magnetic resonance spectroscopy. Overall, we found significantly lower soil carbon stocks in pre-contact agricultural sites compared to reference sites. Radiocarbon dating of bulk soil carbon showed a trend toward older carbon in agricultural versus reference soils, suggesting decreased retention of newer C in agricultural sites. Radiocarbon dating of macroscopic charcoal particles from under agricultural field walls indicated that there were black carbon inputs concurrent with pre-contact agricultural activity. Nonetheless, black carbon and carbonyl carbon levels were lower in agricultural versus reference soils, suggesting decreased retention of specific carbon groups in cultivated sites. Proteins were the only biomolecule higher in abundance in agricultural versus reference sites. Finally, there was an interacting effect of soil mineralogy and historic land use on soil carbon stocks. Whereas short range order (SRO) minerals were positively associated with total soil carbon overall, differences in soil carbon between agricultural and reference soils were largest in soils with high concentrations of SRO minerals. Our results indicate that the negative effect of agriculture on soil carbon stocks can be long-lived, may be associated with persistent changes in soil carbon chemistry, and can vary with soil mineralogical properties.

Vegetation dynamics and anthropogenically forced changes in the Estanilles peat bog (southern Pyrenees) during the last seven millennia

Estanilles peat bog, located in the northeastern Iberian peninsula, was studied to determine the anthropogenic changes in the landscape over the past seven millennia. The pollen diagram and sedimentary charcoal analyses from this site permit us to reconstruct the landscape changes in an area of both Mediterranean and Atlantic influence. In addition, Montarenyo ombrotrophic peat bog was studied to strengthen the analysis of data from more recent centuries. This paper attempts a reconstruction of historical cultural landscapes using two complementary palaeobotanical proxies (pollen and charcoal) in high mountain environments. The macroscopic charcoal record shows a fire signal since 7500 cal. b.p. However, the relationship between fire frequency and human impact is not always linear. This divergence is linked to fuel availability and fire activity. Fire has been used repeatedly to clear ground and to maintain open areas, and has been a key tool for the management of these high mountain areas. The intensity of use of the landscape implies the expansion of agricultural areas into higher altitudes, including cereal cultivation above 2,200 m a.s.l., during the Middle Ages. The first clear human influence detected in the pollen percentage data is recorded between 6000 and 7000 cal. b.p. and, until present times, the greatest changes in vegetation and landscape history occurred during periods of particular specialization in socioeconomic activities during the Middle Ages.

ANÁLISE DE CARVÃO VEGETAL MACROSCÓPICO EM PORÇÕES DO SÍTIO ARQUEOLÓGICO RS-T-101, MARQUES DE SOUZA/RIO GRANDE DO SUL, BRASIL

Anthracology is a multidisciplinary discipline that allows the analysis of charcoal preserved in soils and archaeological sites, for the purpose of studies on climate, vegetation and man-made activities. In order to characterize the fuel used by pre-colonial populations, the present study evaluated the occurrence of charcoal in a Quaternary Age archaeological site in the municipality of Marques de Souza, Rio Grande do Sul state. Macroscopic charcoal fragments were collected from the archaeological site. Using the scheduling technique, process that consists in the layering of the excavation by blasting followed by manual recovery of fragments that resembled charcoal. Samples were analyzed by naked eye and under stereomicroscope. Those wich could be characterized as having charcoal, were separated mechanically and the fragments removed with the aid of spatula, tong and histological needle. The material was examined under SEM (Scanning Electron Microscope) for the establishment of taxonomic affinities. Based on the data was possible to rescue charcoal in a good state of preservation, and defined a combustion temperature between 230o-340o C, observing homogenized cell walls. It was also possible to observe cellular structures in good condition, identifying the fragments as belonging to angiosperms. One of the samples showed the presence of fusioned fungal hyphae.

566 Vegetation and fire history since the last glacial based on pollen and macroscopic charcoal records in the southern area of Mt. Yufu, northeast Kyushu, Japan

566 Vegetation and fire history since the last glacial based on pollen and macroscopic charcoal records in the southern area of Mt. Yufu, northeast Kyushu, Japan

Holocene history of intentional fires and grassland development on the Soni Plateau, Central Japan, reconstructed from phytolith and macroscopic charcoal records within cumulative soils, combined with paleoenvironmental data from mire sediments

Phytolith and macroscopic charcoal in cumulative soils on the Soni Plateau, Central Japan, were evaluated to clarify the Holocene history of intentional fires and grassland development, and to compare the findings with those derived from pollen and charcoal records in sediments taken from a nearby mire in the previous study. Prior to ~1500 cal. BP, Bambusoid short-cell phytoliths and Pleioblastus-type and Bambusoideae-type bulliform cell phytoliths were abundant with scarce charcoal particles (<1000 particles/cm3). In contrast, since ~1500 cal. BP Andropogoneae-type bulliform cell phytoliths and Bilobate short-cell phytoliths were dominant with abundant charcoal particles (>1000 particles/cm3). Based on correlating these records with pollen and charcoal records in mire sediments, prior to ~1500 cal. BP, dwarf bamboo flourished on the forest floor under largely fire-free conditions, whereas since ~1500 cal. BP, grassland dominated by Japanese pampas grass has been sustained by periodic intentional burning that has continued until the present day.

Variability of tundra fire regimes in Arctic Alaska: millennial-scale patterns and ecological implications

Tundra fires have important ecological impacts on vegetation, wildlife, permafrost, and carbon cycling, but the pattern and controls of historic tundra fire regimes are poorly understood. We use sediment records from four lakes to develop a 2000-yr fire and vegetation history in a highly flammable tundra region and compare this history with previously published fire records to examine spatial and temporal variability of tundra burning across Arctic Alaska. The four sites span a modern climatic gradient in the Noatak National Preserve, from warmer, drier down-valley locations to cooler, generally moister up-valley locations. Modern vegetation varies from herb- to shrub-dominated tundra from down- to up-valley sites, and pollen data suggest that this spatial pattern in vegetation persisted over the past two millennia. Peaks in macroscopic charcoal accumulation provide estimates of fire-event return intervals (FRIs), which did not vary significantly at millennial time scales but did vary across space. Down-valley sites burned relatively frequently over the past two millennia, with median FRIs of 150 years (95% CI 101–150) and FRI distributions statistically similar to those from ancient shrub tundra and modern boreal forest. At up-valley sites FRIs were significantly longer than those at down-valley sites, with a median FRI of 218 years (95% CI 128–285). These differences likely reflect the cooler growing-season temperatures and lower evaporative demand at up-valley sites, but local-scale variability in vegetation may have also shaped tundra fire regimes. Comparisons with other long-term fire records in Alaska reveal that the tundra biome can sustain a wide range of burning, with individual FRIs from as low as 30 years to more than 5000 years. These records together indicate that frequent tundra burning has occurred under a range of climatic and vegetation scenarios. The variety of tundra fire histories within Alaska suggests that the ecological impacts of tundra burning likewise vary widely, with important implications for wildlife-habitat maintenance and for the responses of tundra biophysical and biogeochemical processes to climatic change.

Impact of fire on long-term vegetation dynamics of ombrotrophic peatlands in northwestern Québec, Canada

A 7000-year record of local fire history was reconstructed from three ombrotrophic peatlands in the James Bay lowlands (northwestern Québec, Canada) using a high-resolution analysis of macroscopic charcoal (long axis≥0.5mm). The impact of fire on vegetation changes was evaluated using detailed analysis of plant macrofossils. Compared to upland boreal forest, fire incidence in these Sphagnum-dominated bogs is rather low. Past fire occurrence seems to have been controlled primarily by internal processes associated with local hydroseral succession. Size of the peatland basin and distance from the well-drained forest soils also appear to be factors controlling fire occurrence. The impact of peatland fires on long-term vegetation succession appears negligible except in a forested bog, where it initiated the replacement of Sphagnum by mosses. In some circumstances, fire caused marked changes in the bryophyte assemblages over many decades. However, ombrotrophic peatland vegetation is generally resilient to surface fire.

Palaeoecological evidence associated with earth mounds of the Murray Riverine Plain, south-eastern Australia

The characteristic mounded cultural deposits on the Murray Riverine Plain, regionally known as 'mounds', 'earth mounds' or 'oven mounds', are unique archives of palaeoecological information. Excavations of two large mounds on a distributary of the Lower Murrumbidgee River provide tangible evidence of past environments and human exploitation of these environments. The excavation data bridge the nearly 5000-year time gap between the construction of the excavated mounds and the 19th-century ethnohistorical observations linking women to specialised knowledge of wetland management, plant harvesting and preparation, and co-operative cooking in heat retainer ovens on mounds. Macroscopic charcoal, pollen and plant imprints from the mounds suggest that the ethnohistorically observed baking/steaming of carbohydrate-rich wetland plant foods such as Typha, Bolboschoenus and Triglochin in baked clay heat retainer ovens on mounds had its origins during the mid-Holocene. The consistent amounts of wetland faunal bone and shell and the clustered spatial patterning of mounds around specific types of current and former 'reed-beds', swamps and lakes, also provide evidence of a mid to late Holocene focus on wetland environments. This paper aims to encourage new palaeoecological research into these relatively neglected but extremely significant cultural deposits.

Fire history and vegetation recovery in two raised bogs at the Baltic Sea

Questions: What were the bog fire patterns and frequencies in two boreal peatlands during the last 5000 years? What is the nature and time-scale of post-fire vegetation successions? Were fire events related to climate? Location: Mannikjarve bog, central east Estonia; Kontolanrahka bog, southwest Finland. Methods: Macroscopic charcoal, plant macrofossils and radiocarbon dating were examined. Redundancy analysis was used in the assessments. Results: During the last 5000 years, both of the above peatlands have experienced several fire events. A typical pre-fire vegetation community consisted of dry hummock Sphagnum spp., often accompanied by Calluna vulgaris. Only the most severe occasional fires resulted in a dramatic change in the vegetation composition. In these cases, a wet shift occurred, where the pre-fire hummock community was replaced by a wet hollow community. Calluna vulgaris was found to be a key species in both pre- and post-fire vegetation dynamics. The recovery time of dry microtopes following severe combustion and the subsequent hydrological change could take up to 350 years. Even after a long-lasting wet phase, the post-fire disturbance succession led towards a dry hummock community. Conclusions: Fire succession appeared to be cyclic, starting as and developing towards a dry hummock community. Fires have been a regular phenomenon in boreal bogs, even in regions with rather low human impact. The fire history records did not indicate any direct link to the regional long-term climate.