Fire frequency for the transitional mixedwood forest of Timiskaming, Quebec, Canada

2005 ◽  
Vol 35 (3) ◽  
pp. 656-666 ◽  
Author(s):  
Daniel J Grenier ◽  
Yves Bergeron ◽  
Daniel Kneeshaw ◽  
Sylvie Gauthier

Fire history was reconstructed for a 2500-km2 area at the interface between the boreal coniferous and northern hardwood forests of southwestern Quebec. The fire cycle, the time required for an area equal to the study site to burn once over, was described using a random sampling strategy that included dendrochronological techniques in conjunction with provincial and national government archival data. Physiographic elements were not found to spatially influence fire frequency; however, human land-use patterns were observed to significantly affect the fire frequency. A temporal shift in fire frequency was also detected, which coincided with the period of Euro-Canadian colonization and known extreme dry years for the study site. Additionally, a fire-free period was identified in the most recent times that could be associated with fire suppression and climate change. The estimated cycles (approx. 188–314 years) for the southeastern section of the study area were thought to better represent the natural cycles for this transition zone as a result of less anthropogenic influence. The importance of gap-type dynamics becomes evident with the increased presence of old-growth forest, given the derived fire cycle estimations for the region. Even-aged management with short rotations, consequently, is questioned because fire cycle estimations suggest more complex harvest systems using an ecosystem management approach.


1990 ◽  
Vol 68 (8) ◽  
pp. 1763-1767 ◽  
Author(s):  
Alan M. Masters

Time-since-fire distribution analysis is used to estimate forest fire frequency for the 1400 km2 Kootenay National Park, British Columbia, located on the west slope of the Rocky Mountains. The time-since-fire distribution indicates three periods of different fire frequency: 1988 to 1928, 1928 to 1788, and before 1788. The fire cycle for the park was > 2700 years for 1988 to 1928, 130 years between 1928 and 1788, and 60 years between 1778 and 1508. Longer fire cycles after 1788 and 1928 may be due, respectively, to cool climate associated with the Little Ice Age and a recent period of higher precipitation. Contrary to some fire history investigations in the region, neither a fire suppression policy since park establishment in 1919, nor the completion of the Windermere Highway through the park in 1923 appear to have changed the fire frequency from levels during pre-European occupation. Spatial partitioning of the time-since-fire distribution was unsuccessful. No relationship was found between elevation or aspect and fire frequency. Key words: fire cycle, Rocky Mountains, climate change.



2009 ◽  
Vol 18 (1) ◽  
pp. 61 ◽  
Author(s):  
Louis P. Elliott ◽  
Donald C. Franklin ◽  
David M. J. S. Bowman

In savanna environments, fire and grass are inextricably linked by feedback loops. In the Darwin area of northern Australia, flammable tall annual grasses of the genus Sarga (previously Sorghum1) have been implicated in a savanna fire-cycle. We examined the relationship between fire history, the grass layer and distance from settlement using LANDSAT images and plot-based surveys. Areas more than 500 m from settlement were burnt almost twice as often, the additional fires being concentrated late in the dry season and in areas dominated by annual Sarga and even more so where dominated by short annual grasses. Grass cover was a stronger correlate of fire frequency than grass biomass, the two showing a non-linear relationship. Sites dominated by short annual grasses had similar cover to, but markedly lower biomass than those dominated by annual Sarga or perennial grasses. Our results reflect the success of fire suppression in the vicinity of settlements, but little effective management of late dry-season wildfires in remoter areas. We evaluate several hypotheses for the association of frequent fire with annual grasses regardless of their growth form and conclude that fuel connectivity and possibly other fuel characteristics are key issues worthy of further investigation.



2007 ◽  
Vol 13 (3) ◽  
pp. 177 ◽  
Author(s):  
Owen Price ◽  
Bryan Baker

A nine year fire history for the Darwin region was created from Landsat imagery, and examined to describe the fire regime across the region. 43% of the region burned each year, and approximately one quarter of the fires occur in the late dry season, which is lower than most other studied areas. Freehold land, which covers 35% of the greater Darwin region, has 20% long-unburnt land. In contrast, most publicly owned and Aboriginal owned land has very high fire frequency (60-70% per year), and only 5% long unburnt. It seems that much of the Freehold land is managed for fire suppression, while the common land is burnt either to protect the Freehold or by pyromaniacs. Generalized Linear Modelling among a random sample of points revealed that fire frequency is higher among large blocks of savannah vegetation, and at greater distances from mangrove vegetation and roads. This suggests that various kinds of fire break can be used to manage fire in the region. The overall fire frequency in the Darwin region is probably too high and is having a negative impact on wildlife. However, the relatively low proportion of late dry season fires means the regime is probably not as bad as in some other regions. The management of fire is ad-hoc and strongly influenced by tenure. There needs to be a clear statement of regional fire targets and a strategy to achieve these. Continuation of the fire mapping is an essential component of achieving the targets.



2011 ◽  
Vol 20 (2) ◽  
pp. 248 ◽  
Author(s):  
Tuomo Wallenius ◽  
Markku Larjavaara ◽  
Juha Heikkinen ◽  
Olga Shibistova

To study the poorly known fire history of Larix-dominated forest in central Siberia, we collected samples from 200 trees in 46 systematically located study plots. Our study area stretches ~90 km from north to south along the River Nizhnyaya Tunguska in northern Irkustk district. Cross-dated tree-ring chronology for all samples combined extended from the year 1360 AD to the present and included 76 fire years and 88 separate fire events. Average fire cycle gradually lengthened from 52 years in the 18th century to 164 years in the 20th century. During the same time, the number of recorded fires decreased even more steeply, i.e. by more than 85%. Fires were more numerous but smaller in the past. Contrary to expectations, climate change in the 20th century has not resulted in increased forest fires in this region. Fire suppression may have contributed to the scarcity of fires since the 1950s. However, a significant decline in fires was evident earlier; therefore an additional explanation is required, a reduction in human-caused ignitions being likely in the light of historical accounts.



2006 ◽  
Vol 36 (7) ◽  
pp. 1884-1888 ◽  
Author(s):  
William J Reed

The concepts of hazard of burning, fire interval, and fire cycle are considered. It is claimed that the current notion of fire cycle is poorly defined, since the time required to burn a specified area is a random variable. It is shown that the expected time to burn an area equal in size to the study area normally exceeds the fire interval (the average time between fires at any location). In view of this, it is recommended that the notion of fire cycle in its current form be abandoned.



2001 ◽  
Vol 31 (8) ◽  
pp. 1437-1443 ◽  
Author(s):  
Durland L Shumway ◽  
Marc D Abrams ◽  
Charles M Ruffner

We document the fire history and associated ecological changes of an old-growth forest stand in western Maryland, U.S.A. The study area is located on the side slopes of a ridge system (Savage Mountain). Twenty basal cross sections were obtained from old trees cut in 1986, which provided evidence of 42 fires from 1615 to 1958. Nine fires were recorded in the sample trees in the 17th century, 13 in the 18th century, 12 in the 19th century, and eight in the early to mid-20th century. However, there were no major fire years after 1930. The Weibull modal fire interval was 7.6 years. Oaks recruited consistently from the early 1600s to the early 1900s, but there was increased Acer rubrum L. and Betula lenta L. recruitment with fire suppression after 1930. Species recruitment patterns and long-term fire history reported in this study offer important direct support for the hypothesis that periodic fire played an important role in the historical development and perpetuation of oak forests of the mid-Atlantic region before and after European settlement.



2005 ◽  
Vol 14 (3) ◽  
pp. 285 ◽  
Author(s):  
Jon E. Keeley

The San Francisco East Bay landscape is a rich mosaic of grasslands, shrublands and woodlands that is experiencing losses of grassland due to colonization by shrubs and succession towards woodland associations. The instability of these grasslands is apparently due to their disturbance-dependent nature coupled with 20th century changes in fire and grazing activity. This study uses fire history records to determine the potential for fire in this region and for evidence of changes in the second half of the 20th century that would account for shrubland expansion. This region has a largely anthropogenic fire regime with no lightning-ignited fires in most years. Fire suppression policy has not excluded fire from this region; however, it has been effective at maintaining roughly similar burning levels in the face of increasing anthropogenic fires, and effective at decreasing the size of fires. Fire frequency parallels increasing population growth until the latter part of the 20th century, when it reached a plateau. Fire does not appear to have been a major factor in the shrub colonization of grasslands, and cessation of grazing is a more likely immediate cause. Because grasslands are not under strong edaphic control, rather their distribution appears to be disturbance-dependent, and natural lightning ignitions are rare in the region, I hypothesize that, before the entrance of people into the region, grasslands were of limited extent. Native Americans played a major role in creation of grasslands through repeated burning and these disturbance-dependent grasslands were maintained by early European settlers through overstocking of these range lands with cattle and sheep. Twentieth century reduction in grazing, coupled with a lack of natural fires and effective suppression of anthropogenic fires, have acted in concert to favor shrubland expansion.



2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Guilherme Alexandre Stecher Justini Pinto ◽  
Mats Niklasson ◽  
Nina Ryzhkova ◽  
Igor Drobyshev

AbstractThe Sala fire in the Västmanland County of central Sweden that burned about 14,000 ha in 2014 has been the largest fire recorded in the modern history of Sweden. To understand the long-term fire history of this area, we dendrochronologically dated fire scars on Scots pine (Pinus sylvestris L.) trees (live and deadwood) to reconstruct the fire cycle and fire occurrence in the area affected by the 2014 fire. We identified 64 fire years, using a total of 378 pine samples. The earliest reconstructed fire dated back to 1113 AD. The spatial reconstruction extended over the period of 1480–2018 AD. Lower levels of fire activity (fire cycle, FC = 43 years, with the central 90% of the distribution limited by 35 to 57 years) dominated in the earlier period (1480–1690 AD) that was followed by a strong decrease in fire activity since 1700 (FC = 403 years, with 90% of the distribution being within 149 to 7308 years), with a fire-free period between 1756 and 2014. Sala area, therefore, features the earliest known onset of fire suppression in Scandinavia. The high demand for timber during the peak in mining activities in the study area around the 1700–1800s, accompanied by passive fire suppression policies, were possibly the main drivers of the decline in fire activity. Superposed epoch analysis (SEA) did not show significant departures in the drought proxy during the ten years with the largest area burned between 1480 and1690. It is unclear whether the result is due to the relatively small area sampled or an indication that human controls of fires dominated during that period. However, significant departures during the following period with low fire activity (1700–1756), which just preceded the last fire-free period, suggested that the climate became an increasingly important driver of fire during the onset of the suppression period. We speculate that the lack of major firebreaks, the homogenization of forests, and the lack of burned areas with low fuel loads might contribute to the occurrence of the exceptionally large 2014 fire in Sala.



2001 ◽  
Vol 31 (8) ◽  
pp. 1462-1466 ◽  
Author(s):  
K Miyanishi ◽  
E A Johnson

A report by Ward and Tithecott (P.C. Ward and A.G. Tithecott. 1993. Ontario Ministry of Natural Resources, Aviation, Flood and Fire Management Branch, Publ. 305.) is frequently cited in the literature as providing evidence of the effects of fire suppression on the boreal forest. The study is based on 15 years of fire data and stand age data from Ontario, Canada. A re-examination of this report reveals serious flaws that invalidate the conclusions regarding effects of fire suppression on fire size and fire frequency. The fire-size data from the unprotected zone are censored in the small size classes because of detection resolution, invalidating comparisons of shapes of the distributions between the protected and unprotected zones. Use of different plotting scales gives the false appearance of large differences in the number of large fires between the two zones. Stand age data are used to show a change in fire frequency in the 20th century, and this change is attributed to fire suppression. However, no evidence is presented to conclude that this change in fire frequency is attributable to fire suppression and not to climate change. The estimate of the current fire cycle is based on too short a record to give a reliable estimate given the variation in annual area burned. Therefore, this report does not present sound evidence of fire suppression effects and should not be cited as such.



2016 ◽  
Vol 38 (4) ◽  
pp. 391 ◽  
Author(s):  
J. L. Silcock ◽  
G. B. Witt ◽  
R. J. Fensham

Changes to fire regimes associated with European colonisation are implicated in declines in biodiversity and productivity in rangelands globally. However, for many areas there is incomplete knowledge of historical fire regimes and purported changes can become accepted wisdom with little empirical evidence. In the Mulga Lands of south-western Queensland, the dominant narrative implicates reduced fire frequency as a cause of woody vegetation thickening. We present a fire history of the Mulga Lands since pastoral exploration in the 1840s based on a review of explorer and early pastoralist journals, newspaper articles, interviews with long-term landholders and collation of satellite imagery. Fires in mulga communities are infrequent and only occur after at least two years of above-average summer rainfall. The assumption of regular pre-pastoral fires is not supported by available evidence. Since pastoral settlement in the 1860s, fire events affecting >1000 km2 have occurred seven times (1891–1892, 1904, 1918, 1950–1951, 1956–1957, 1976–1979 and 2011–2013), with only the 1950s fires affecting a >10% of the total area of mulga-dominated vegetation. We argue that fire is limited by fuel loads, which are in turn limited by rainfall events occurring only a few times a century. Even in the absence of grazing and active fire suppression fire intervals would be extremely long, perhaps 30–50 years in relatively fire-prone communities and much longer throughout most of the region. Combined with quantitative studies of fire and tree and shrub population dynamics, detailed fire histories will allow for more informed and nuanced debates about the role of fire in rangelands subject to abrupt management upheavals.



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