Journal articles on the topic 'Fire scar history'
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1
Baker, William L., and Alexa J. Dugan. "Fire-history implications of fire scarring." Canadian Journal of Forest Research 43, no. 10 (October 2013): 951–62. http://dx.doi.org/10.1139/cjfr-2013-0176.
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Fire scars are widely used to reconstruct fire history, yet patterns of scarring are poorly understood, hampering effective sampling and analysis. Factors that influence the probability a tree will receive a scar (SP) and the fraction of trees that scar (SF) are little studied. We analyzed scarring in 16 fires in ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) forests in northern Arizona. SP was significantly related to char height, presence of a preceding scar, tree diameter, and years since a preceding fire. Mean SF was 0.375, but varied from 0.121 to 0.728, with SF significantly higher with higher mean char height, larger scar dimensions, higher fire severity, larger tree diameter, and where no preceding fire had burned within 30 years. The expected healing times exceeded 55 years for 33% of scars and 100 years for 11% of scars. Scars with a preceding scar were 38% larger than new scars, with expected healing about 20–25 years longer. Scars were clustered, particularly at scales from >20 to >40 m. Scar directions generally aligned with fire-spread directions, which were complex. Variability in SF complicates fire-history methods that use fire counts rather then area burned. Methods that account for spatial and temporal variability in the abundance of evidence are needed.
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Holz, A., S. Haberle, T. T. Veblen, R. De Pol-Holz, and J. Southon. "Fire history in western Patagonia from paired tree-ring fire-scar and charcoal records." Climate of the Past 8, no. 2 (March 9, 2012): 451–66. http://dx.doi.org/10.5194/cp-8-451-2012.
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Abstract. Fire history reconstructions are typically based on tree ages and tree-ring fire scars or on charcoal in sedimentary records from lakes or bogs, but rarely on both. In this study of fire history in western Patagonia (47–48° S) in southern South America (SSA) we compared three sedimentary charcoal records collected in bogs with tree-ring fire-scar data collected at 13 nearby sample sites. We examined the temporal and spatial correspondence between the two fire proxies and also compared them to published charcoal records from distant sites in SSA, and with published proxy reconstructions of regional climate variability and large-scale climate modes. Two of our three charcoal records record fire activity for the last 4 ka yr and one for the last 11 ka yr. For the last ca. 400 yr, charcoal accumulation peaks tend to coincide with high fire activity in the tree-ring fire scar records, but the charcoal records failed to detect some of the fire activity recorded by tree rings. Potentially, this discrepancy reflects low-severity fires that burn in herbaceous and other fine fuels without depositing charcoal in the sedimentary record. Periods of high fire activity tended to be synchronous across sample areas, across proxy types, and with proxy records of regional climatic variability as well as major climate drivers. Fire activity throughout the Holocene in western Patagonia has responded to regional climate variation affecting a broad region of southern South America that is teleconnected to both tropical- and high-latitude climate drivers-El Niño-Southern Oscillation and the Southern Annular Mode. An early Holocene peak in fire activity pre-dates any known human presence in our study area, and consequently implicates lightning as the ignition source. In contrast, the increased fire activity during the 20th century, which was concomitantly recorded by charcoal from all the sampled bogs and at all fire-scar sample sites, is attributed to human-set fires and is outside the range of variability characteristic of these ecosystems over many centuries and probably millennia.
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Holz, A., S. Haberle, T. T. Veblen, R. De Pol-Holz, and J. Southon. "Fire history in western Patagonia from paired tree-ring fire-scar and charcoal records." Climate of the Past Discussions 7, no. 5 (October 10, 2011): 3203–38. http://dx.doi.org/10.5194/cpd-7-3203-2011.
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Abstract. Fire history reconstructions are typically based on tree ages and tree-ring fire scars or on charcoal in sedimentary records from lakes or bogs, but rarely on both. In this study of fire history in western Patagonia (47–48° S) in southern South America (SSA) we compared three sedimentary charcoal records collected in bogs with tree-ring fire-scar data collected at 13 nearby sample sites. We examined the temporal and spatial correspondence between the two fire proxies and also compared them to published charcoal records from distant sites in SSA, and with published proxy reconstructions of regional climate variability and large-scale climate modes. Two of our three charcoal records show fire activity for the last 4ka yrs and one for the last 11 ka yr. For the last ca. 400 yr, charcoal accumulation peaks tend to coincide with high fire activity in the tree-ring fire scar records, but the charcoal records failed to detect some of the fire activity recorded by tree rings. Potentially, this discrepancy reflects low-severity fires that burn in herbaceous and other fine fuels without depositing charcoal in the sedimentary record. Periods of high fire activity tended to be synchronous across sample areas, across proxy types, and with proxy records of regional climatic variability as well as major climate drivers. Fire activity throughout the Holocene in western Patagonia has responded to regional climate variation affecting a broad region of southern South America that is teleconnected to both tropical- and high-latitude climate drivers – El Nino-Southern Oscillation and the Southern Annular Mode. An early Holocene peak in fire activity pre-dates any known human presence in our study area, and consequently implicates lightning as the ignition source. In contrast, the increased fire activity during the 20th century, which was concomitantly recorded by charcoal from all the sampled bogs and at all fire-scar sample sites, is attributed to human-set fires and is outside the range of variability characteristic of these ecosystems over many centuries and probably millennia.
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Piha, Aura, Timo Kuuluvainen, Henrik Lindberg, and Ilkka Vanha-Majamaa. "Can scar-based fire history reconstructions be biased? An experimental study in boreal Scots pine." Canadian Journal of Forest Research 43, no. 7 (July 2013): 669–75. http://dx.doi.org/10.1139/cjfr-2012-0471.
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Determining forest fire history is commonly based on fire scar dating with dendrochronological methods. We used an experimental setup to investigate the impacts of low-intensity prescribed fire on fire scar formation 8 years after fire in 12 young managed Scots pine (Pinus sylvestris L.) stands. Five stands were between 30 and 35 years old and seven were 45 years old at the time of burning. A total of 217 fire scars were recorded in 142 trees. The number of separate scars per tree originating from a single fire ranged from 1 to 6, with 67% of the trees having just one scar. The proportion of fire-scarred trees out of all trees per plot ranged from 0% to 30%, averaging 16.5% in young stands and 2.8% in older stands. Four of the 12 burned plots did not have any trees with fire scars, and these were all in the older age group. This means that in the older stands, in only three of seven plots (43%) did the fire leave scars from which fire can potentially be detected and dated afterwards. Our results suggest that fire scar dating in Scots pine dominated forests may underestimate fire frequency, area, and the importance of historically common low-intensity surface fires in dendrochronological reconstructions of past fire histories.
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Huffman, David W., Peter Z. Fulé, Kristen M. Pearson, and Joseph E. Crouse. "Fire history of pinyon–juniper woodlands at upper ecotones with ponderosa pine forests in Arizona and New Mexico." Canadian Journal of Forest Research 38, no. 8 (August 2008): 2097–108. http://dx.doi.org/10.1139/x08-053.
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We used maps of fire evidence, fire scar dendrochronology, forest age-structure analysis, and landscape analysis to investigate fire history at pinyon pine ( Pinus edulis Engelm.) – juniper ( Juniperus osteosperma (Torr.) Little, Juniperus scopulorum Sarg.) woodland – ponderosa pine ( Pinus ponderosa P. & C. Lawson) forest ecotones in Arizona (Tusayan) and in New Mexico (Canjilon). Results showed that charred trees were not evenly distributed across vegetative communities but were significantly (p < 0.001) more abundant than expected in ponderosa pine communities. Composite fire scar analysis indicated that surface fires occurred in ponderosa pine stands at both sites and burned at intervals of 7.2–11.1 years (WMPI; Weibull median probability interval). At Tusayan, landscape structure was fine grained, and maximum pinyon age was >200 years across 80% of the site. At Canjilon, landscape pattern was relatively coarse, and most pinyon patches were 200–300 years old. Cumulative standing age distributions suggested pinyon–juniper fire rotations of 340 and 290 years at Tusayan and Canjilon, respectively. We concluded the following: (i) surface fires in ponderosa pine stands did not spread through pinyon–juniper communities at either site, (ii) fire evidence was prevalent across both sites, but old pinyon trees indicated that no widespread lethal fires had occurred in the last 300–400 years, and (iii) structurally heterogeneous landscapes suggested that historical pinyon–juniper fires were of limited extent but lethal in patches.
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Baker, William L., and Donna Ehle. "Uncertainty in surface-fire history: the case of ponderosa pine forests in the western United States." Canadian Journal of Forest Research 31, no. 7 (July 1, 2001): 1205–26. http://dx.doi.org/10.1139/x01-046.
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Present understanding of fire ecology in forests subject to surface fires is based on fire-scar evidence. We present theory and empirical results that suggest that fire-history data have uncertainties and biases when used to estimate the population mean fire interval (FI) or other parameters of the fire regime. First, the population mean FI is difficult to estimate precisely because of unrecorded fires and can only be shown to lie in a broad range. Second, the interval between tree origin and first fire scar estimates a real fire-free interval that warrants inclusion in mean-FI calculations. Finally, inadequate sampling and targeting of multiple-scarred trees and high scar densities bias mean FIs toward shorter intervals. In ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) forests of the western United States, these uncertainties and biases suggest that reported mean FIs of 2-25 years significantly underestimate population mean FIs, which instead may be between 22 and 308 years. We suggest that uncertainty be explicitly stated in fire-history results by bracketing the range of possible population mean FIs. Research and improved methods may narrow the range, but there is no statistical or other method that can eliminate all uncertainty. Longer mean FIs in ponderosa pine forests suggest that (i) surface fire is still important, but less so in maintaining forest structure, and (ii) some dense patches of trees may have occurred in the pre-Euro-American landscape. Creation of low-density forest structure across all parts of ponderosa pine landscapes, particularly in valuable parks and reserves, is not supported by these results.
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Wu, Yegang, and Dennis Knight. "Fire History and Potential Fire Behavior in a Rocky Mountain Foothill Landscape." UW National Parks Service Research Station Annual Reports 14 (January 1, 1990): 29. http://dx.doi.org/10.13001/uwnpsrc.1990.2861.
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A landscape approach was used to study fire history and fire behavior in the Douglas-fir forests and foothill vegetation of the Bighorn Canyon National Recreation Area in southcentral Montana. The 3,976 ha study area was divided into 4-ha grid cells, and traditional fire scar analysis and fuel sampling methods were used for data collection in each cell. There have been 15 surface fires during the last 109 years and 10 canopy fires during the last 360 years. The mean fire interval in the forests as a whole, was 7 years for surface fires and 31 years for canopy fires. Using the Weibull function, the recurrent time for fire in a specific grid cell was 212 and 226 years for surface and canopy fires, respectively. The distribution of the probability density function showed that there was a peak of high canopy fire frequency between 150-250 years of stand age. There was no obvious peak period for surface fires in humid ravines, which suggests that surface fires there are not associated with aging. Employing Rothermel's model, a fire behavior model (FIREMDL) was developed and linked it to a geographic information system (GRASS) to simulate flammability of each grid cell under different conditions of fuel moisture and wind velocity. The results suggest that flammability is highly variable because of differences in vegetation and topographic position.
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Brown, Peter M., and Thomas W. Swetnam. "A cross-dated fire history from coast redwood near Redwood National Park, California." Canadian Journal of Forest Research 24, no. 1 (January 1, 1994): 21–31. http://dx.doi.org/10.1139/x94-004.
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Cross sections from coast redwood trees (Sequoiasempervirens (D.Don.)Endl.) in and near Redwood National Park were dendrochronologically cross-dated and used to develop a fire history from 1714 to 1985. A master chronology for the study area was first developed from old-growth trees and provided dating control for fire-scarred samples. Redwood offers a challenge for dendrochronology owing to partially absent rings (ring wedging) and uniform ring widths (complacency). Cross dating was successful in portions of 12 of 24 fire-scarred trees. Fire events were dated by noting the position of fire scars and other fire-associated ring structures (resin ducts, double latewood, growth releases, and ring separations) in the cross-dated ring series. Using only dates of fire scars, the mean fire interval (MFI) was 9.9 years from the first recorded fire in 1714 to the last in 1962. The MFI was 8.0 years for the best represented (greatest sample depth) presettlement period from 1714 to 1881. Using dates for all fire-associated ring features, the MFI from 1714 to 1962 was 7.0 years and from 1714 to 1881 was 6.0 years. Use of all fire-associated ring characteristics is argued to be a more complete representation of past fire frequency due to possible under-representation of fire-scar records from stump-top samples. Based upon scar positions within annual rings, fires occurred predominately late in the growing season or after growth ceased for the year. The mean fire intervals determined are shorter than those reported in all except one other fire history study from coast redwood and suggest that fire frequency in redwood may have been underestimated in many past studies.
9
McEwan, Ryan W., Todd F. Hutchinson, Robert D. Ford, and Brian C. McCarthy. "An experimental evaluation of fire history reconstruction using dendrochronology in white oak (Quercus alba)." Canadian Journal of Forest Research 37, no. 4 (April 2007): 806–16. http://dx.doi.org/10.1139/x06-294.
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Dendrochronological analysis of fire scars on tree cross sections has been critically important for understanding historical fire regimes and has influenced forest management practices. Despite its value as a tool for understanding historical ecosystems, tree-ring-based fire history reconstruction has rarely been experimentally evaluated. To examine the efficacy of dendrochronological analysis for detecting fire occurrence in oak forests, we analyzed tree cross sections from sites in which prescribed fires had been recently conducted. The first fire in each treatment unit created a scar in at least one sample, but the overall percentage of samples containing scars in fire years was low (12%). We found that scars were created by 10 of the 15 prescribed fires, and the five undetected fires all occurred in sites where fire had occurred the previous year. Notably, several samples contained scars from known fire-free periods. In summary, our data suggest that tree-ring analysis is a generally effective tool for reconstructing historical fire regimes, although the following points of uncertainty were highlighted: (i) consecutive annual burns may not create fire scars and (ii) wounds that are morphologically indistinguishable from fire scars may originate from nonfire sources.
10
Kou, Xiaojun, and William L. Baker. "Accurate estimation of mean fire interval for managing fire." International Journal of Wildland Fire 15, no. 4 (2006): 489. http://dx.doi.org/10.1071/wf05113.
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Accurate fire-history data are needed if local management of fire or costly national plans for restoring and managing fire and forest structure are to succeed. Fire-history researchers often use fire scars and the composite fire interval method to reconstruct parameters of past fire regimes, such as the population mean fire interval, but the composite method has serious limitations. We modified an alternative non-composite fire interval method, the individual-tree fire-interval method, to derive a more accurate new method, the all-tree fire-interval method. A stochastic fire-scar generating model to assess the accuracy of the new method and its predecessors was then used. Three factors (scarring ratio, population mean fire interval, and tree age) that affect accuracy were varied in the model runs. More complexity (trees with varied scarring ratio between the first scar and successive scars) also was modelled to test the robustness of the method. The all-tree fire-interval method was shown to greatly improve accuracy and provide unbiased estimates of the population mean fire interval. The method also produced encouraging results when scarring was more complex. The new all-tree fire-interval method will require further research on the rates at which trees are scarred by fire, but this would be generally beneficial to understanding fire history.
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Margolis, Ellis Q., Thomas W. Swetnam, and Craig D. Allen. "A stand-replacing fire history in upper montane forests of the southern Rocky Mountains." Canadian Journal of Forest Research 37, no. 11 (November 2007): 2227–41. http://dx.doi.org/10.1139/x07-079.
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Dendroecological techniques were applied to reconstruct stand-replacing fire history in upper montane forests in northern New Mexico and southern Colorado. Fourteen stand-replacing fires were dated to 8 unique fire years (1842–1901) using four lines of evidence at each of 12 sites within the upper Rio Grande Basin. The four lines of evidence were (i) quaking aspen ( Populus tremuloides Michx.) inner-ring dates, (ii) fire-killed conifer bark-ring dates, (iii) tree-ring width changes or other morphological indicators of injury, and (iv) fire scars. The annual precision of dating allowed the identification of synchronous stand-replacing fire years among the sites, and co-occurrence with regional surface fire events previously reconstructed from a network of fire scar collections in lower elevation pine forests across the southwestern United States. Nearly all of the synchronous stand-replacing and surface fire years coincided with severe droughts, because climate variability created regional conditions where stand-replacing fires and surface fires burned across ecosystems. Reconstructed stand-replacing fires that predate substantial Anglo-American settlement in this region provide direct evidence that stand-replacing fires were a feature of high-elevation forests before extensive and intensive land-use practices (e.g., logging, railroad, and mining) began in the late 19th century.
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Sherriff, Rosemary L., and Thomas T. Veblen. "Variability in fire - climate relationships in ponderosa pine forests in the Colorado Front Range." International Journal of Wildland Fire 17, no. 1 (2008): 50. http://dx.doi.org/10.1071/wf07029.
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Understanding the interactions of climate variability and wildfire has been a primary objective of recent fire history research. The present study examines the influence of El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) on fire occurrence using fire-scar evidence from 58 sites from the lower ecotone to the upper elevational limits of ponderosa pine (Pinus ponderosa) in northern Colorado. An important finding is that at low v. high elevations within the montane zone, climatic patterns conducive to years of widespread fire are different. Differences in fire–climate relationships are manifested primarily in antecedent year climate. Below ~2100 m, fires are dependent on antecedent moister conditions that favour fine fuel accumulation 2 years before dry fire years. In the upper montane zone, fires are dependent primarily on drought rather than an increase in fine fuels. Throughout the montane zone, fire is strongly linked to variations in moisture availability that in turn is linked to climate influences of ENSO, PDO and AMO. Fire occurrence is greater than expected during the phases of each index associated with drought. Regionally widespread fire years are associated with specific phase combinations of ENSO, PDO and AMO. In particular, the combination of La Niña, negative PDO and positive AMO is highly conducive to widespread fire.
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Pitcher, Donald C. "Fire history and age structure in red fir forests of Sequoia National Park, California." Canadian Journal of Forest Research 17, no. 7 (July 1, 1987): 582–87. http://dx.doi.org/10.1139/x87-098.
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The relationship between historical fires and age structure was examined on three plots in red fir (Abiesmagnifica var. shastensis Lemm.) forests within Sequoia National Park, California, U.S.A. All trees greater than 0.1 m in height were mapped and aged. Fire history was determined from 16 fire-scar sections. Red fir trees are more shade tolerant, longer lived, larger, and slower growing than western white pine (Pinusmonticola Dougl.) on the plots. No fires have occurred since 1886, but prior to that time the average fire-free interval was 65 years. Most of the trees on two of the plots originated after fires, but on the third plot red fir regeneration was delayed for at least 60 years following the last fire. Structural differences between the plots were linked to variations in fire behavior. The decrease in fire frequencies in this century may have led to a decrease in red fir establishment. Excluding the most recent period, the forest age structure is in something of a steady state that approximates a negative exponential age-class distribution.
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Gartner, Meredith H., Thomas T. Veblen, Rosemary L. Sherriff, and Tania L. Schoennagel. "Proximity to grasslands influences fire frequency and sensitivity to climate variability in ponderosa pine forests of the Colorado Front Range." International Journal of Wildland Fire 21, no. 5 (2012): 562. http://dx.doi.org/10.1071/wf10103.
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This study examines the influence of grasslands on fire frequency and occurrence in the ponderosa pine (Pinus ponderosa)-dominated forests of the central and northern Colorado Front Range. Fire frequency based on tree-ring fire-scar data was compared between 34 fire history sites adjacent to grasslands and 34 fire history sites not adjacent to grasslands for the time period 1675–1920. Relationships were examined between fire occurrence and values of the Palmer Drought Severity Index and sea-surface temperatures from the NINO3 region of the tropical Pacific Ocean (positive values indicating El Niño-like conditions and negative values La Niña-like conditions). Ponderosa pine stands adjacent to grasslands experienced more frequent fire than stands not adjacent to grasslands (P < 0.05) owing to proximity to prevalent fine fuels able to support relatively frequent surface fires. Fire activity adjacent to grasslands showed a lagged positive relationship with moist years (positive Palmer Drought Severity Index and positive NINO3) antecedent to fire events whereas fire occurrence at sites not adjacent to grasslands showed no relationship to antecedent moist years. This study illustrates how the presence of grasslands in a ponderosa pine landscape results in increased fire frequency (a bottom–up influence) and also increases the sensitivity of fire activity to interannual climate variability (a top–down influence).
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Brown, PM, and CH Sieg. "Fire History in Interior Ponderosa Pine Communities of the Black Hills, South Dakota, USA." International Journal of Wildland Fire 6, no. 3 (1996): 97. http://dx.doi.org/10.1071/wf9960097.
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Chronologies of fire events were reconstructed from crossdated fire-scarred ponderosa pine trees for four sites in the south-central Black Hills. Compared to other ponderosa pine forests in the southwest US or southern Rocky Mountains, these communities burned less frequently. For all sites combined, and using all fires detected, the mean fire interval (MFI), or number of years between fire years, was 16 years (± 14 SD) for the period 1388 to 1900. When a yearly minimum percentage of trees recording scars of ≥ 25% is imposed, the MFI was 20 years (± 14 SD). The length of the most recent fire-free period (104 years, from 1890 to 1994) exceeds the longest intervals in the pre-settlement era (before ca. 1874), and is likely the result of human-induced land use changes. Based on fire scar position within annual rings, most past fires occurred late in the growing season or after growth had ceased for the year. These findings have important implications for management of ponderosa pine forests in the Black Hills and for understanding the role of fire in pre-settlement ecosystem function.
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Mann, Daniel H., F. Brett Engstrom, and Jill L. Bubier. "Fire History and Tree Recruitment in an Uncut New England Forest." Quaternary Research 42, no. 2 (September 1994): 206–15. http://dx.doi.org/10.1006/qres.1994.1070.
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AbstractFire and forest histories in a hemlock-pine forest in Vermont have been reconstructed by dating fire scars and reconstructing the age distributions of living and dead trees. The ages of living red pines, white pines, and hemlocks show that most of the present forest germinated after a series of spatially overlapping fires between A.D. 1790 and 1850. The ages of cross-dated, dead red pines indicate that this was the third major recruitment interval for pines in this forest since ca. A.D. 1450. We interpret the fire scar and tree age data as recording ca. 50-yr intervals of increased fire frequency recurring every 100-200 yr in response to accumulating fuel loads that coincide with summer drought. The historical records of fires and tree ages, together with the present fuel load, suggest that the next interval of stand-regenerating fires is now overdue. Our success in cross-dating the remnants of dead red pines as old as the 15th century A.D. holds promise for extending reconstructions of fire, forest, and climate history in other parts of this tree's range.
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Harley, Grant L., Henri D. Grissino-Mayer, and Sally P. Horn. "Fire history and forest structure of an endangered subtropical ecosystem in the Florida Keys, USA." International Journal of Wildland Fire 22, no. 3 (2013): 394. http://dx.doi.org/10.1071/wf12071.
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We focussed on the influence of historical fire and varied fire management practices on the structure of globally endangered pine rockland ecosystems on two adjacent islands in the Florida Keys: Big Pine Key and No Name Key. We reconstructed fire history in two stands from fire scars on South Florida slash pines (Pinus elliottii Engelm. var. densa Little & Dor.) that were accurately dated using dendrochronology, and quantified stand structure to infer successional trajectories. Fire regimes on Big Pine Key and No Name Key over the past 150 years differed in fire return interval and spatial extent. Fire scar analysis indicated that fires burnt at intervals of 6 and 9 years (Weibull median probability interval) on Big Pine Key and No Name Key with the majority of fires occurring late in the growing season. On Big Pine Key, pine recruitment was widespread, likely due to multiple, widespread prescribed burns conducted since 2000. No Name Key experienced fewer fires than Big Pine Key, but pines recruited at the site from at least the 1890s through the 1970s. Today, pine recruitment is nearly absent on No Name Key, where fire management practices since 1957 could result in loss of pine rockland habitat.
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Saladyga, Thomas. "Dwarf Blackgum (Nyssa sylvatica) Contains Datable Fire Scars that Complement an Existing Fire History." Fire 2, no. 4 (December 9, 2019): 61. http://dx.doi.org/10.3390/fire2040061.
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Blackgum (Nyssa sylvatica) is a “consummate subordinate” hardwood tree species consigned to the mid-canopy of many eastern North American forests. Despite its wide distribution and ecological amplitude, blackgum is an underutilized tree species in fire history reconstructions within its range. In this study, I analyzed cross-section samples collected from 19 fire-scarred blackgum trees at a dry, nutrient-poor ridgetop study area in northeastern Pennsylvania. All but two of these samples were successfully crossdated, each containing between one and six fire scars. Fires recorded by blackgum occurred frequently, with site-level mean fire intervals between approximately three and five years. There was an increase in blackgum growth within two years following fire events, but this increase was not statistically significant and it was dependent on local fire regime characteristics. In addition, the blackgum fire-scar data increased the temporal and spatial resolution of an existing local fire history. These results provide evidence for the potential use of blackgum in fire history reconstructions, but applications may be limited by tree age, complacent growth that prevents crossdating, and the degree of rot resistance after scarring.
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Barrett, Stephen, and Stephen Arno. "Fire History of the Lamar River Drainage Yellowstone National Park." UW National Parks Service Research Station Annual Reports 14 (January 1, 1990): 131–33. http://dx.doi.org/10.13001/uwnpsrc.1990.2911.
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In this paper we discuss the first phase of a 3-year effort to document the fire history of Yellowstone National Park's (YNP) Lamar River drainage southeast of Soda Butte Creek. The overall goal of the study was to provide managers with a more complete understanding of YNP natural fire regimes. Specific objectives were: 1. Determine natural (pre-1900) fire periodicities, severities, burning patterns, and post-fire succession within the study area's major forest types (Douglas fir/ grassland, lodgepole pine/subalpine fir/ spruce, whitebark pine/lodgepole pine/ subalpine fir, and whitebark pine/subalpine fir timberline habitats); 2. document and map the pre-1988 forest age-class mosaic; and 3. digitize the age-class mosaic map for the YNP's GIS data base. This study is considered especially timely because the 1988 fires destroyed much evidence of area fire history. Our sampling in 1989 focused on a 24,000 ha area encompassing the Cache Creek drainage, which was severely burned in 1988. The forest age-class mosaic was sampled by increment boring and sawing fire scar samples from old trees (Arno and Sneck 1977, Barrett and Arno 1988). Aerial photographs were used to map the pre-1988 forest age-class mosaic; Data was digitized for the park's GIS data base. Information from the YNP fire atlas also was useful in interpreting fire patterns during the post-1900 period.
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Van Horne, Megan L., and Peter Z. Fulé. "Comparing methods of reconstructing fire history using fire scars in a southwestern United States ponderosa pine forest." Canadian Journal of Forest Research 36, no. 4 (April 1, 2006): 855–67. http://dx.doi.org/10.1139/x05-289.
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Fire scars have been used to understand the historical role of fire in ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) ecosystems, but sampling methods and interpretation of results have been criticized for being statistically invalid and biased and for leading to exaggerated estimates of fire frequency. We compared "targeted" sampling, random sampling, and grid-based sampling to a census of all 1479 fire-scarred trees in a 1 km2 study site in northern Arizona. Of these trees, 1246 were sufficiently intact to collect cross-sections; of these, 648 had fire scars that could be cross-dated to the year of occurrence in the 200-year analysis period. Given a sufficient sample size (approximately n ≥ 50), we concluded that all tested sampling methods resulted in accurate estimates of the census fire frequency, with mean fire intervals within 1 year of the census mean. We also assessed three analytical techniques: (1) fire intervals from individual trees, (2) the interval between the tree origin and the first scar, and (3) proportional filtering. "Bracketing" fire regime statistics to account for purported uncertainty associated with targeted sampling was not useful. Quantifying differences in sampling approaches cannot resolve all the limitations of fire-scar methods, but does strengthen interpretation of these data.
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Cerano-Paredes, Julián, Dante A. Rodríguez-Trejo, José M. Iniguez, Rosalinda Cervantes-Martínez, José Villanueva-Díaz, and Osvaldo Franco-Ramos. "Fire History (1896–2013) in an Abies religiosa Forest in the Sierra Norte of Puebla, Mexico." Forests 12, no. 6 (May 28, 2021): 700. http://dx.doi.org/10.3390/f12060700.
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The oyamel forests, as Abies dominated forests are commonly known as, register their largest distribution (95% of their population) along the Trans-Mexican Volcanic Belt (TMVB). Although efforts have been made to study these forests with various approaches, dendrochronology-based studies have been limited, particularly in pure Abies forests in this region. The objective of this study was to reconstruct fire regimes in an Abies religiosa forest in the Sierra Norte in the state of Puebla, Mexico. Within an area of 50-ha, we collected 40 fire-scar samples, which were processed and analyzed using dendrochronological techniques to identify 153 fire scars. The fire history was reconstructed for a period of 118 years (1896–2013), with low severity surface fires occurring mainly during in the spring (92.8%) and summer (7.2%). Over the past century, fires were frequent, with an mean fire interval (MFI) and Weibull median probability of (WMPI) of five years when considering all fire scars and less than 10 years for fires covering larger areas (fires recorded by ≥25% of samples). Extensive fires were synchronized with drought conditions based on Ring Width Indexes, Palmer Drought Severity Index (PDSI) and El Niño Southern Oscillation (ENSO). After 1983, we observed a change in fire frequencies attributed to regulated management. Longer fire intervals within the last several decades are likely leading to increased fuel accumulations and could potentially result in more severe fires in the future, threatening the sustainability of these forests. Based on our finding, we recommend management actions (silvicultural or prescribed fire) to reduce fuels and the risk of severe fires, particularly in the face of climatic changes.
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Farris, Calvin A., Christopher H. Baisan, Donald A. Falk, Megan L. Van Horne, Peter Z. Fulé, and Thomas W. Swetnam. "A comparison of targeted and systematic fire-scar sampling for estimating historical fire frequency in south-western ponderosa pine forests." International Journal of Wildland Fire 22, no. 8 (2013): 1021. http://dx.doi.org/10.1071/wf13026.
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Fire history researchers employ various forms of search-based sampling to target specimens that contain visible evidence of well preserved fire scars. Targeted sampling is considered to be the most efficient way to increase the completeness and length of the fire-scar record, but the accuracy of this method for estimating landscape-scale fire frequency parameters compared with probabilistic (i.e. systematic and random) sampling is poorly understood. In this study we compared metrics of temporal and spatial fire occurrence reconstructed independently from targeted and probabilistic fire-scar sampling to identify potential differences in parameter estimation in south-western ponderosa pine forests. Data were analysed for three case studies spanning a broad geographic range of ponderosa pine ecosystems across the US Southwest at multiple spatial scales: Centennial Forest in northern Arizona (100ha); Monument Canyon Research Natural Area (RNA) in central New Mexico (256ha); and Mica Mountain in southern Arizona (2780ha). We found that the percentage of available samples that recorded individual fire years (i.e. fire-scar synchrony) was correlated strongly between targeted and probabilistic datasets at all three study areas (r=0.85, 0.96 and 0.91 respectively). These strong positive correlations resulted predictably in similar estimates of commonly used statistical measures of fire frequency and cumulative area burned, including Mean Fire Return Interval (MFI) and Natural Fire Rotation (NFR). Consistent with theoretical expectations, targeted fire-scar sampling resulted in greater overall sampling efficiency and lower rates of sample attrition. Our findings demonstrate that targeted sampling in these systems can produce accurate estimates of landscape-scale fire frequency parameters relative to intensive probabilistic sampling.
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Smith, D. R., J. D. Kaduk, H. Balzter, M. J. Wooster, G. N. Mottram, T. J. Lynham, J. Studens, J. Curry, G. Hartley, and B. J. Stocks. "Soil respiration in a fire scar chronosequence of Canadian boreal jack pine forest." Biogeosciences Discussions 6, no. 5 (September 3, 2009): 8725–73. http://dx.doi.org/10.5194/bgd-6-8725-2009.
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Abstract. To fully understand the carbon (C) cycle impacts of forest fires, both C emissions during the fire and post-disturbance fluxes need to be considered. The latter are dominated by soil respiration (Rs), which is still subject to large uncertainties. This research investigates Rs in a boreal jack pine fire scar chronosequence at Sharpsand Creek, Ontario, Canada. During two field campaigns in 2006 and 2007, Rs was measured in a chronosequence of fire scars aged between 0 and 59 years since the last fire. Mean Rs per fire scar was adjusted for soil temperature (Ts) and soil moisture (Ms) (denoted RST,M). RST,M ranged from 0.56 μmol CO2/m2/s (32 years post fire) to 8.18 μmol CO2/m2/s (58 years post fire). The coefficient of variation (CV) of RST,M ranged from 20% (16 years post fire) to 56% (58 years post fire). Across the field site, there was a statistically highly significant exponential relationship between Rs adjusted for soil organic carbon (Cs) and Ts (P<0.00001; Q10=2.21) but no effect of Ms on Rs adjusted for Cs and Ts for the range 0.21 to 0.77 volumetric Ms (P=0.702). RST,M decreased significantly (P=0.030) after fire (4 to 8 days post fire) in mature forest, though no significant (P>0.1) difference could be detected between recently burned (4 to 8 days post fire) and unburned young forest. There were significant differences in RST,M between recently burned (4 to 8 days post fire) scar age categories that differed in their burn history, with between-fire intervals of 32 vs. 16 years (P<0.001) and 32 vs 59 years (P=0.044). There was a highly significant exponential increase in RST,M with time since fire (r2=0.999; P=0.006) for the chronosequence 0, 16 and 59 years post fire, and for all these age categories, RST,M was significantly different from one another (P<0.05). The results of this study contribute to a better quantitative understanding of Rs in boreal jack pine fire scars and will facilitate improvements in C cycle modelling. Further work is needed in quantifying autotrophic and heterotrophic contributions to Rs in jack pine systems; in monitoring Rs for extended time periods after fire; and in measuring different fire-prone forest types.
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Clark, James S. "Stratigraphic Charcoal Analysis on Petrographic Thin Sections: Application to Fire History in Northwestern Minnesota." Quaternary Research 30, no. 1 (July 1988): 81–91. http://dx.doi.org/10.1016/0033-5894(88)90089-0.
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Results of stratigraphic charcoal analysis from thin sections of varved lake sediments have been compared with fire scars on red pine trees in northwestern Minnesota to determine if charcoal data accurately reflect fire regimes. Pollen and opaque-spherule analyses were completed from a short core to confirm that laminations were annual over the last 350 yr. A good correspondence was found between fossil-charcoal and fire-scar data. Individual fires could be identified as specific peaks in the charcoal curves, and times of reduced fire frequency were reflected in the charcoal data. Charcoal was absent during the fire-suppression era from 1920 A.D. to the present. Distinct charcoal maxima from 1864 to 1920 occurred at times of fire within the lake catchment. Fire was less frequent during the 19th century, and charcoal was substantially less abundant. Fire was frequent from 1760 to 1815, and charcoal was abundant continuously. Fire scars and fossil charcoal indicate that fires did not occur during 1730–1750 and 1670–1700. Several fires occurred from 1640 to 1670 and 1700 to 1730. Charcoal counted from pollen preparations in the area generally do not show this changing fire regime. Simulated “sampling” of the thin-section data in a fashion comparable to pollen-slide methods suggests that sampling alone is not sufficient to account for differences between the two methods. Integrating annual charcoal values in this fashion still produced much higher resolution than the pollen-slide method, and the postfire suppression decline of charcoal characteristic of my method (but not of pollen slides) is still evident. Consideration of the differences in size of fragments counted by the two methods is necessary to explain charcoal representation in lake sediments.
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Finney, Mark A., and Robert E. Martin. "Fire history in a Sequoiasempervirens forest at Salt Point State Park, California." Canadian Journal of Forest Research 19, no. 11 (November 1, 1989): 1451–57. http://dx.doi.org/10.1139/x89-221.
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Fire occurrence data between the 12th and 20th centuries were obtained from analysis of fire scars on coast redwood (Sequoiasempervirens (D. Don.) Endl.) and bishop pine (Pinusmuricata D. Don.). Mean fire intervals were calculated for settlement and presettlement periods from fire scar samples individually (point data) and from composites of samples aggregated within three approximately 200-ha study areas. Mean fire intervals from point data (20.5 to 29.0 years) were more than three times greater than mean intervals from composite data (6.1 to 9.3 years). Mean fire intervals derived from point data compared well with values previously reported, although substantial bias ascribed to point data suggests that these values for mean fire intervals in redwood forest communities are too large. A period of significantly longer fire intervals during the 17th century was suggested by analysis of fire intervals by century and using a moving average.
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Jenkins, Michael. "Fire Histoy Determination in the Mixed Conifer/Aspen Community of Bryce Canyon National Park." UW National Parks Service Research Station Annual Reports 17 (January 1, 1993): 31–35. http://dx.doi.org/10.13001/uwnpsrc.1993.3135.
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The major objective of this ongoing study is to document vegetative changes resulting from alteration of the fire regime in the mixed conifer/aspen communities of Bryce Canyon National Park. Previous fire history studies have documented fire return intervals using fire scar analysis of ponderosa pine Pinus ponderosa in the park (Buchannan and Tolman 1983: Wight 1989) and for the Paunsaugunt Plateau (Stein 1988). Numerous other studies have similarly documented the fire regime in pre-European settlement ponderosa pine forests in western North America. The study is being conducted in the more mesic mixed conifer communities at the south end of Bryce Canyon National Park and will specifically document vegetative changes suggested by Roberts et al. (1992) resulting from suppression of frequent low intensity surface fires and overgrazing.
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Stivrins, Normunds, Tuomas Aakala, Liisa Ilvonen, Leena Pasanen, Timo Kuuluvainen, Harri Vasander, Mariusz Gałka, et al. "Integrating fire-scar, charcoal and fungal spore data to study fire events in the boreal forest of northern Europe." Holocene 29, no. 9 (June 11, 2019): 1480–90. http://dx.doi.org/10.1177/0959683619854524.
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Fire is a major disturbance agent in the boreal forest, influencing many current and future ecosystem conditions and services. Surprisingly few studies have attempted to improve the accuracy of fire-event reconstructions even though the estimates of the occurrence of past fires may be biased, influencing the reliability of the models employing those data (e.g. C stock, cycle). This study aimed to demonstrate how three types of fire proxies – fire scars from tree rings, sedimentary charcoal and, for the first time in this context, fungal spores of Neurospora – can be integrated to achieve a better understanding of past fire dynamics. By studying charcoal and Neurospora from sediment cores from forest hollows, and the fire scars from tree rings in their surroundings in the southern Fennoscandian and western Russian boreal forest, we produced composite fire-event data sets and fire-event frequencies, and estimated fire return intervals. Our estimates show that the fire return interval varied between 126 and 237 years during the last 11,000 years. The highest fire frequency during the 18th–19th century can be associated with the anthropogenic influence. Importantly, statistical tests revealed a positive relationship between other fire event indicators and Neurospora occurrence allowing us to pinpoint past fire events at times when the sedimentary charcoal was absent, but Neurospora were abundant. We demonstrated how fire proxies with different temporal resolution can be linked, providing potential improvements in the reliability of fire history reconstructions from multiple proxies.
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Farris, Calvin A., Christopher H. Baisan, Donald A. Falk, Stephen R. Yool, and Thomas W. Swetnam. "Spatial and temporal corroboration of a fire-scar-based fire history in a frequently burned ponderosa pine forest." Ecological Applications 20, no. 6 (September 2010): 1598–614. http://dx.doi.org/10.1890/09-1535.1.
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Arizpe, Alexis H., Donald A. Falk, Connie A. Woodhouse, and Thomas W. Swetnam. "Widespread fire years in the US–Mexico Sky Islands are contingent on both winter and monsoon precipitation." International Journal of Wildland Fire 29, no. 12 (2020): 1072. http://dx.doi.org/10.1071/wf19181.
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The climate of the south-western United States and northern Mexico borderlands is marked by a bimodal precipitation regime with the majority of moisture arriving during the cool season via Pacific frontal storm systems, and intense convective storms during the North American Monsoon (NAM). The fire season occurs primarily during the arid foresummer in May and June, before the development of the NAM. Most tree-ring studies of fire climatology in the region have evaluated only the role of winter precipitation. We used tree-ring-width-based reconstructions of both winter and monsoon precipitation, coupled with fire scar reconstructions of fire history from mountain ranges in the US and Mexico, to quantify the historical role and interactions of both seasons of precipitation in modulating widespread fire years. Winter precipitation was the primary driver of widespread fire years in the region, but years with drought in both seasons had the highest fire frequency and most widespread fires. These relationships define a unique monsoon fire regime, in which the timing and amount of monsoon precipitation are important factors in limiting the length of fire season and regulating widespread fire years.
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Stephens, Scott L., Liam Maier, Lilah Gonen, Jennifer D. York, Brandon M. Collins, and Danny L. Fry. "Variation in fire scar phenology from mixed conifer trees in the Sierra Nevada." Canadian Journal of Forest Research 48, no. 1 (January 2018): 101–4. http://dx.doi.org/10.1139/cjfr-2017-0297.
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Fire scar based studies have provided robust reconstructions of past fire regimes. The season in which a fire occurs can have considerable impacts to ecosystems but inference on seasonality from fire scars is relatively uncertain. This study examined patterns in the phenology of cambium formation and wounding responses in the five common mixed conifer tree species of the Sierra Nevada. The outer bark was shaved on 35 trees and individual locations within the shaved portions were wounded systematically by applying direct heat using a handheld torch. Most of the trees had not commenced annual ring development by the first burning treatment in late May. By the second treatment, scars were identified mostly within the early or middle earlywood, although variation was high compared with other treatment periods. By late October, all scars were recorded at the ring boundary. Although intra-ring scar positions generally followed a logical temporal pattern, there was high tree to tree variation such as Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) burned on 26 June induced scars in the early, mid, and late earlywood depending on the individual tree. This high variation makes it somewhat challenging to precisely assign past fire season to published fire history studies.
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Donnegan, Joseph A., Thomas T. Veblen, and Jason S. Sibold. "Climatic and human influences on fire history in Pike National Forest, central Colorado." Canadian Journal of Forest Research 31, no. 9 (September 1, 2001): 1526–39. http://dx.doi.org/10.1139/x01-093.
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We investigated interannual and multidecadal variability in fire regimes, as related to climate and human land-use in Pike National Forest, central Colorado. Short and long-term trends in fire-scar records were related to tree-ring proxy records of moisture availability and to variability in El Niño Southern Oscillation (ENSO). Fire occurrence is strongly tied to interannual drought conditions and is associated with cycles of ENSO. Fire events tend to occur in years of reduced moisture availability (La Niña years) and are often preceded by 24 years of increased moisture availability (El Niño years). A period of reduced variability in the tree-ring record from 1760 to 1820 AD, roughly corresponds to a period of reduced fire occurrence from approximately 1792 to 1842. Coincident with increased fire occurrence, variability in the climate proxies was high in the middle to late 1800s until the early 1900s. Multidecadal impacts through land use are also evident in the fire record with sharp increases during Euro-American settlement in ca. 1850 and abrupt declines with the start of active fire suppression after ca. 1920. Both humans and climatic variation appear to have interacted synergistically to create long-term trends in fire occurrence over the past two centuries.
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Heyerdahl, Emily K., Ken Lertzman, and Carmen M. Wong. "Mixed-severity fire regimes in dry forests of southern interior British Columbia, Canada." Canadian Journal of Forest Research 42, no. 1 (January 2012): 88–98. http://dx.doi.org/10.1139/x11-160.
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Historical fire severity is poorly characterized for dry forests in the interior west of North America. We inferred a multicentury history of fire severity from tree rings in Douglas-fir ( Pseudotsuga menziesii var. glauca (Beissn.) Franco) – ponderosa pine ( Pinus ponderosa Douglas ex P. Lawson & C. Lawson) forests in the southern interior of British Columbia, Canada. In 2 ha plots distributed systematically over 1105 ha, we determined the dates of fire scars, indicators of low-severity fire, from 125 trees and inferred dates of even-aged cohorts, potential indicators of high-severity fire, from establishment dates of 1270 trees. Most (76%) of the 41 plots contained fire-scarred trees with a mean plot-composite fire scar interval of 21 years (1700–1900). Most (76%) also contained one or two cohorts. At the plot scale, we inferred that the fire regime at most plots was of mixed severity through time (66%) and at the remaining plots of low (20%), high (10%), or unknown (4%) severity through time. We suggest that across our study area, the fire regime was mixed severity over the past several centuries, with low-severity fires most common and often extensive but small, high-severity disturbances also occasionally occurred. Our results present strong evidence for the importance of mixed-severity fire regimes in which low-severity fires dominate in interior Douglas-fir – ponderosa pine forests in western Canada.
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Fulé, Peter Z., Thomas A. Heinlein, and W. Wallace Covington. "Fire histories in ponderosa pine forests of Grand Canyon are well supported: reply to Baker." International Journal of Wildland Fire 15, no. 3 (2006): 439. http://dx.doi.org/10.1071/wf06048.
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Fire scars and other paleoecological methods are imperfect proxies for detecting past patterns of fire events. However, calculations of long fire rotations in Grand Canyon ponderosa pine forests by Baker are not convincing in methodology or assumptions compared with fire-scar evidence of frequent surface fires. Patches of severe disturbance are a possible hypothesis to explain the relatively short age structure at the park, where ~12% fewer trees were older than 300 years compared with another unharvested northern Arizona site. However, mapped patterns of old trees as well as the evidence for frequent surface fire from fire scars, charcoal deposition studies, and evolutionary history are more consistent with the dominance of surface fire prior to c. 1880. The most relevant available evidence of fire recurrence at a given point, mean point fire intervals, had median values <16 years at all five study sites, close to filtered composite fire interval statistics (~6–10 years), but much lower than Baker’s calculated fire rotation values (55–110 years). The composite fire interval is not a uniquely important statistic or a numerical guideline for management, but one of many lines of evidence underscoring the ecological role of frequent surface fire in ponderosa pine forests.
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Whitlock, Cathy, Carl N. Skinner, Patrick J. Bartlein, Thomas Minckley, and Jerry A. Mohr. "Comparison of charcoal and tree-ring records of recent fires in the eastern Klamath Mountains, California, USA." Canadian Journal of Forest Research 34, no. 10 (October 1, 2004): 2110–21. http://dx.doi.org/10.1139/x04-084.
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Fire-history reconstructions are based on tree-ring records that span the last few centuries and charcoal data from lake-sediment cores that extend back several thousand years. The two approaches have unique strengths and weaknesses in their ability to depict past fire events and fire regimes, and most comparisons of these datasets in western conifer forests have focused on sites characterized by high-severity crown fires. Tree-ring and charcoal data spanning the last 300 years in four watersheds in the montane forests of the Klamath Mountains provided an opportunity to compare the records in a fire regime of frequent low- to moderate-severity surface events. The charcoal data were obtained from small lakes, and tree-ring records were derived from fire-scar chronologies at multiple sites within each watershed. The comparison indicates that the tree-ring records detected individual fires not evident in the lake-sediment profiles, whereas the charcoal data disclosed variations in fuel loading and general levels of burning at broader spatial scales. Regional burning in the late 19th and early 20th centuries was evident in the lake-sediment records, and both datasets registered a decline in fire activity in the late 20th century. Thus, the two types of data provide complementary as well as supplementary information on past fire conditions.
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McClaran, Mitchel P., and James W. Bartolome. "Fire-related recruitment in stagnant Quercusdouglasii populations." Canadian Journal of Forest Research 19, no. 5 (May 1, 1989): 580–85. http://dx.doi.org/10.1139/x89-091.
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Quercusdouglasii H. & A. (blue oak) age structure, stem analysis, and fire-scar history from more than 500 individuals on two sites in central California, U.S.A., revealed (i) meager tree recruitment since the 1940s and few trees older than 150 years, (ii) increased fire frequency following Anglo-American settlement in 1848 until fire suppression efforts in the 1940s, (iii) a positive association between tree ages and fire dates, and (iv) superior vertical growth to 135 cm of postfire sprouts (trees with ground-level ages within 1 year after fires) on the site with less livestock browsing pressure. We suggest that the association between tree ages and fire dates may have resulted from temporal concentration of postfire seedling sprouts, and faster vertical growth of postfire sprouts compared with true seedlings. However, sampling from existing trees may dampen the difference in vertical growth rates between sprouts and true seedlings where there is heavy browsing, because only true seedlings that grew as fast as sprouts survived and were available for sampling. Our findings contradict previous assumptions of the negative role of fire in Q. douglasii recruitment, and suggest that low recruitment since the 1940s in partly due to fire suppression.
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Smith, Kevin T., Estelle Arbellay, Donald A. Falk, and Elaine Kennedy Sutherland. "Macroanatomy and compartmentalization of recent fire scars in three North American conifers." Canadian Journal of Forest Research 46, no. 4 (April 2016): 535–42. http://dx.doi.org/10.1139/cjfr-2015-0377.
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Fire scars are initiated by cambial necrosis caused by localized lethal heating of the tree stem. Scars develop as part of the linked survival processes of compartmentalization and wound closure. The position of scars within dated tree ring series is the basis for dendrochronological reconstruction of fire history. Macroanatomical features were described for western larch (Larix occidentalis Nutt.), ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson), and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) injured by fire in 2003 and harvested in 2011 at the Lolo National Forest near Missoula, Montana, USA. Bark scorch did not necessarily indicate the formation of a scar. Wound-initiated discoloration inward from the scar face was bounded tangentially by reaction zones. In western larch, the transition between earlywood and latewood was much less abrupt in woundwood rings than in rings formed the same year but not associated with a scar. Wood formed the year after injury contained tangential rows of resin ducts in the earlywood. Compartmentalization plays a key role in resisting the spread of infection and the loss of healthy sapwood and heartwood. Wound closure restores some degree of circumferential continuity of the vascular cambium and reinforces stem structure. The terminology presented here should facilitate communication among tree pathologists, wound anatomists, and dendrochronologists.
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Brown, Peter M., and Anna W. Schoettle. "Fire and stand history in two limber pine (Pinus flexilis) and Rocky Mountain bristlecone pine (Pinus aristata) stands in Colorado." International Journal of Wildland Fire 17, no. 3 (2008): 339. http://dx.doi.org/10.1071/wf06159.
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We developed fire-scar and tree-recruitment chronologies from two stands dominated by limber pine and Rocky Mountain bristlecone pine in central and northern Colorado. Population structures in both sites exhibit reverse-J patterns common in uneven-aged forests. Bristlecone pine trees were older than any other at the site or in the limber pine stand, with the oldest tree dating to 780 AD and several dating to the 1000s and 1100s. The oldest trees in the limber pine stand date to the 1400s, with a majority of recruitment after an apparent bark beetle outbreak in the early 1800s. Spatial patterning in the limber pine suggests that the oldest trees established from seed caches left by corvid birds. Fire scars present in the early part of each chronology document that surface fire regimes dominated during certain periods. Decreased fire frequency, increased tree recruitment, and changes in species composition from the 1600s to1800s in the bristlecone pine may be reflective of cooler and wetter conditions during the Little Ice Age. Results suggest that a recent (1978) severe fire in the bristlecone pine stand that caused complete tree mortality was outside the historical range of variability in fire severity for at least the past ~1000 years.
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Allen, Craig D., R. Scott Anderson, Renata B. Jass, Jaime L. Toney, and Christopher H. Baisan. "Paired charcoal and tree-ring records of high-frequency Holocene fire from two New Mexico bog sites." International Journal of Wildland Fire 17, no. 1 (2008): 115. http://dx.doi.org/10.1071/wf07165.
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Two primary methods for reconstructing paleofire occurrence include dendrochronological dating of fire scars and stand ages from live or dead trees (extending back centuries into the past) and sedimentary records of charcoal particles from lakes and bogs, providing perspectives on fire history that can extend back for many thousands of years. Studies using both proxies have become more common in regions where lakes are present and fire frequencies are low, but are rare where high-frequency surface fires dominate and sedimentary deposits are primarily bogs and wetlands. Here we investigate sedimentary and fire-scar records of fire in two small watersheds in northern New Mexico, in settings recently characterised by relatively high-frequency fire where bogs and wetlands (Chihuahueños Bog and Alamo Bog) are more common than lakes. Our research demonstrates that: (1) essential features of the sedimentary charcoal record can be reproduced between multiple cores within a bog deposit; (2) evidence from both fire-scarred trees and charcoal deposits documents an anomalous lack of fire since ~1900, compared with the remainder of the Holocene; (3) sedimentary charcoal records probably underestimate the recurrence of fire events at these high-frequency fire sites; and (4) the sedimentary records from these bogs are complicated by factors such as burning and oxidation of these organic deposits, diversity of vegetation patterns within watersheds, and potential bioturbation by ungulates. We consider a suite of particular challenges in developing and interpreting fire histories from bog and wetland settings in the Southwest. The identification of these issues and constraints with interpretation of sedimentary charcoal fire records does not diminish their essential utility in assessing millennial-scale patterns of fire activity in this dry part of North America.
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Clark, James S. "Twentieth-century climate change, fire suppression, and forest production and decomposition in northwestern Minnesota." Canadian Journal of Forest Research 20, no. 2 (February 1, 1990): 219–32. http://dx.doi.org/10.1139/x90-031.
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Long-term fire, climate, and vegetation data were used together with simulation models to estimate the effects of 20th century climate change and fire suppression on fire regime and organic-matter accumulation in mixed-conifer stands of Itasca State Park, northwestern Minnesota. Spatial and temporal patterns of fire occurrence and forest composition over the last 150 years determined by stratigraphic charcoal, fire-scar, tree-ring, and pollen analyses in separate studies provide evidence for vegetation and fire relationships. Water balances constructed from temperature and precipitation data collected since 1840 were used to model fire probability and intensity of burn before fire suppression which began in 1910. Existing patterns of biomass accumulation in forest-floor, herb, shrub, and tree components were compared with fire history and topographic variability to provide a spatial perspective on fire effects. Simulation models used these relationships to estimate (i) how accumulation of organic matter had changed through the past under the different fire regimes that prevailed on different topographic aspects, (ii) the changes brought about by fire suppression in 1910, and (iii) the fire regimes and their effects that would have prevailed since fire suppression with the warm–dry climate of the 20th century. Humus, litter, shrubs, and herb cover were less abundant and more variable spatially and temporally before fire suppression. Spatial variability in forest-floor organic matter, which resulted from different fire frequencies in different vegetation and topographic settings before fire suppression, was largely gone by 1920 as a result of fire suppression. Had fire suppression not been instituted in 1910, fire frequency would have increased by 20–40% in the 20th century because of warmer and drier conditions. Forest-floor oganic matter would have been largely depleted by frequent and severe fires exposing mineral soils, particularly during the drought years of the 1930s. Herb biomass would have increased, shrubs would have been more variable, and tree seedling establishment would have been substantially altered. Time required for buildup of fuels limits the extent to which increased moisture deficits increase fire frequency.
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Desponts, Mireille, and Serge Payette. "Recent dynamics of jack pine at its northern distribution limit in northern Quebec." Canadian Journal of Botany 70, no. 6 (June 1, 1992): 1157–67. http://dx.doi.org/10.1139/b92-144.
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The northernmost jack pine (Pinus banksiana Lamb.) populations in northern Quebec are located at the boreal forest–forest tundra boundary, along the Grande rivière de la Baleine, where they colonize the sandy terraces affected by recurrent fires. The recent fire history in the study area, as deduced from fire scar and age structure data, spans a 216-year period from 1773 to 1988. Forest fires occurred on the sites at intervals averaging 40 to 80 years. The analysis of 19 coniferous stands (jack pine and black spruce (Picea mariana (Mill.) Bsp)) indicated that forest communities younger than 67 years old were open jack pine – Cladina mitis or jack pine – black spruce – C. mitis woodlands, while the oldest stands, more than 132 years old, were dominated by jack pine, black spruce, and Cladina stellaris. Stands less than 67-years-old had an age structure almost normally distributed and regeneration often occurred within less than 30 years after fire in both species, while most stands older than 132 years had a multiaged structure. In sites with a prolonged fire-free interval, jack pine was overgrown by black spruce. Spruce woodlands have developed on sites where the organic layer was relatively thick and continuous and they are the end result of the postfire successional process. However, at several sites both conifer species showed an ability to regenerate in prolonged absence of fire disturbance, particularly in open sites with exposed mineral substrates. At the regional scale, fire frequency during the last 200 years has been high enough to prevent pine exclusion at its range limit. The key requirement for the long-term maintenance of jack pine populations is that fires return at intervals shorter than the average life-span of individual trees. It is concluded that the northernmost jack pine populations are able to maintain and regenerate under present fire conditions. Key words: fire, subarctic, jack pine, postfire regeneration, boreal forest.
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Clear, Jennifer L., Chiara Molinari, and Richard H. W. Bradshaw. "Holocene fire in Fennoscandia and Denmark." International Journal of Wildland Fire 23, no. 6 (2014): 781. http://dx.doi.org/10.1071/wf13188.
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Natural disturbance dynamics, such as fire, have a fundamental control on forest composition and structure. Knowledge of fire history and the dominant drivers of fire are becoming increasingly important for conservation and management practice. Temporal and spatial variability in biomass burning is examined here using 170 charcoal and 15 fire scar records collated throughout Fennoscandia and Denmark. The changing fire regime is discussed in relation to local biogeographical controls, regional climatic change, anthropogenic land use and fire suppression. The region has experienced episodic variability in the dominant drivers of biomass burning throughout the Holocene, creating a frequently changing fire regime. Early Holocene biomass burning appears to be driven by fuel availability. Increased continentality during the mid-Holocene Thermal Maximum coincides with an increase in fire. The mid–late Holocene front-like spread of Picea abies (Norway spruce) and cooler, wetter climatic conditions reduce local biomass burning before the onset of intensified anthropogenic land use, and the late Holocene increase in anthropogenic activity created artificially high records of biomass burning that overshadowed the natural fire signal. An economic shift from extensive subsistence land use to agriculture and forestry as well as active fire suppression has reduced regional biomass burning. However, it is proposed that without anthropogenic fire suppression, the underlying natural fire signal would remain low because of the now widespread dominance of P. abies.
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Nelson, John L., Charles M. Ruffner, John W. Groninger, and Ray A. Souter. "Drainage and agriculture impacts on fire frequency in a southern Illinois forested bottomland." Canadian Journal of Forest Research 38, no. 12 (December 2008): 2932–41. http://dx.doi.org/10.1139/x08-129.
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Postsettlement (1909–2003) fire history of a forested bottomland in the Mississippi Embayment of southern Illinois, USA, was determined using fire-scar analysis. The study area is a forested bottomland hardwood site, with remnant pockets of the dominant presettlement bald cypress – tupelo (Taxodium–Nyssa) vegetation. Ditch drainage was installed in 1919, with agricultural clearing and abandonment varying throughout the early and mid-twentieth century. Commercial agricultural activities ceased after the site became part of a conservation area ca. 1950. The hydrology of the site was further modified in 1957 when it was inundated for waterfowl management. Both drainage and land clearing for agriculture were associated with increased fire frequency. Although drainage was a necessary precursor to agriculture across much of this landscape, land improvement played the stronger role in determining fire frequency. The mean fire interval for the study period (1895–1965) was 1.73 years, with a minimum of 1 year and a maximum of 15 years. This frequency contrasts with the complete fire exclusion that has prevailed in the area since 1965. These results have important implications for the maintenance and restoration of forested wetland ecosystems where the present fire regime differs dramatically from that under which the now-dominant forest vegetation developed.
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Soucy, Rick D., Eric Heitzman, and Martin A. Spetich. "The establishment and development of oak forests in the Ozark Mountains of Arkansas." Canadian Journal of Forest Research 35, no. 8 (August 1, 2005): 1790–97. http://dx.doi.org/10.1139/x05-104.
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The disturbance history of six mature white oak (Quercus alba L.) northern red oak (Quercus rubra L.) hickory (Carya spp.) stands in the Ozark Mountains of northern Arkansas were reconstructed using tree-ring and fire-scar analysis. Results indicate that all six stands originated in the early 1900s following timber harvesting and (or) fire. These disturbances initiated a pulse of oak-dominated establishment. Most sites were periodically burned during the next several decades. Abrupt radial growth increases in all stands during the 1920s to 1940s reflected additional disturbances. These perturbations likely provided growing space for existing trees, but did not result in increased seedling establishment. Thus, multiple disturbances were important in the origin and development of the stands studied. By the 1930s and 1940s, oak establishment was replaced by shade-tolerant, fire-intolerant non-oak species; few oak recruited into tree size classes after the 1950s. The decrease in oaks and the increase in non-oaks coincided with fire suppression. Few scars were recorded during the past 6070 years. Prescribed fire may be an important management tool in regenerating oak forests in northern Arkansas.
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Agarwal, Prateek, and Samuel Edward Navon. "Xtra focus pinhole IOL (Morchers GMBH) a novel approach to tackle irregular astigmatism and large pupillary defects with a single step surgery." BMJ Case Reports 12, no. 4 (April 2019): e228902. http://dx.doi.org/10.1136/bcr-2018-228902.
Full textAbstract:
A 69-year-old patient presented to us with traumatic mydriasis with irregular pupil measuring 7 mm, with superior loss of iris tissue and large inferior peripheral iridotomy and pseudophakia. The patient had history of blunt trauma 3 years ago in a fire cracker injury. He was operated elsewhere primarily after the trauma for cataract surgery with intraocular lens implantation and had suboptimal visual outcome with glare and photophobia. He presented to us with irregular pupil and inferior iridectomy with pseudophakia. The uncorrected visual acuity was 20/150 improving to 20/50 with glasses. He had a history of cataract surgery with intraocular lens (IOL) implantation done elsewhere several years back. The patient was not a diabetic or hypertensive. There was a para central corneal scar causing irregular corneal astigmatism. Extra focus pinhole IOL was implanted in sulcus having a pinhole aperture 1.36 mm. Preoperative total corneal higher-order aberrations were 3.3 µ and total corneal coma was 0.97 µ. Postoperatively uncorrected distance visual acuity improved to 20/40 intermediate uncorrected visual acuity improved to 20/30 and uncorrected near visual acuity was J3.
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Duncan, Richard P., and Glenn H. Stewart. "The temporal and spatial analysis of tree age distributions." Canadian Journal of Forest Research 21, no. 12 (December 1, 1991): 1703–10. http://dx.doi.org/10.1139/x91-236.
Full textAbstract:
The temporal and spatial patterns of tree establishment and stand disturbance history are often based on the interpretation of age-class frequency distributions. In particular, the presence of even-aged groups of trees is often used as compelling evidence of past disturbance. However, even-aged groups of trees may be indistinguishable in an age distribution if several different-aged patches occur, especially if their ages overlap. For two different types of forest we used spatial autocorrelation analysis to statistically test for the presence of even-aged patches in tree age data. Ordination and cluster analysis were subsequently applied to a matrix of association measures that reflected both spatial proximity and age similarity to identify even-aged groups of trees. Although the method worked well for our forests, which contained light-demanding tree species, it is likely to be less applicable to forests dominated by shade-tolerant species, because trees may be of many different ages if they were present as suppressed individuals prior to disturbance. However, in these instances the method could be usefully applied in other types of analysis, such as the distribution of growth release dates, tree-fall or fire-scar dates, and growth rates.
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Du, James Xianxing. "Bilingual Biblical Etymology - Origin of Language." International Journal of Linguistics 12, no. 5 (September 20, 2020): 30. http://dx.doi.org/10.5296/ijl.v12i5.17716.
Full textAbstract:
Multilingual mutual match in biblical etymology is a secret of civilization and definitive evidence for creation, presented for the first time in history. 恐terror is error to carry ark by two poles工to battlefield, 謬mistake is to take ark marked by cherubim to shed blood , 奉 dedication has two dactyl hands to offer cattle as tithe, 祝blessing is sibling兄, 嬰Infant is financial貝to fiancé and fiancée, 音Sound has Son童, sonic is in prison , 辨to distinguish digital hands is related to Jonah’s debate辯, 諒to forgive is related to whale鲸and capital京, and黥criminal label has capital after殳killing Abel from穀grain offering. Biblical books such as Genesis, Exodus, Leviticus and Jonah are astonishingly validated by bilingual mutual match in biblical etymology. Bilingual mutual match links退quit to quite很, 骄pride to bridge桥, 宴banquet to bank堰, 霉mould to plum blossom梅, 園garden to garment衣, 悛repent to paternal公Adam, 悔remorse to maternal母Eve, 濁opacity to optic目, 稠dense to seeds禾on altar口, 脯sausage to use用, 恿urge to courage勇, religion to grill and logged legal book, 忿anger and rage to revenge in segregation分, and朝morning to mourn悼. Many affixes are presented, such as nat+vowel of native, innate and nation as tone, wh as human near water, 乍restricted motion in炸explosion, migration to circumvent giant巨, a motion affix , 夭human to flee, 匽to hide Moses in basket near Nile bank堰, 兆water and fire, co-carriage of ark and altar, 用/甬/甫as altar’s service, and as star. Known affixes such as com, tech, 巴, , 貝and曼curtain also match biblical etymology. 爸father is to thaw fat肥in faith at thermal altar, 疤scar has sacred worshiper巴, and relative is related to altar. Creatures have biblical etymology. Clove is created to resemble cloud, tendril resembles spilled blood lines on tent’s curtain, 藤vine has vineyard , vessel舟, fire and Noah’s hands , dolphin has phonic ultrasound, and elephant has elevated sound. The systematic bilingual match in biblical etymology spans all categories. Wednesday is water condensation and seed day, 奥/謎 mystery has star , 樂music, smile and laugh have semi and halves, 球sphere/globe is ephod/robe裘’s pomegranate, textile has to exit in exile, filament has flame, fiber has fire, desperation is to tear apart dress, inheritance and heritage繼are to tear attire and fragment斷garment, 亵blasphemy is to take执divided clothes for military to humiliate Son, satire has attire, mock is blocked sunlight, Corpse is sacred Sarco on cross, 讽sarcasm is Sarco and crazy疯to validate Jesus, oath is to heat theological offering cut with hatchet, family has flame for kin to kindle, meal in flame is alumni, to incite is to incinerate, to instigate is to ignite, to stimulate is meal at flame of altar, health is to heat wheat at altar, tomb is mobility, and town is own tone and own tower, solving the etymology of numerous words. In conclusion, the entire languages of English and China and also words in additional ancient languages must have been divinely created in etymology to predestinedly and mutually match each other, and equally astonishingly, match bible, as the origin of language.
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Dwivedi, Urvashee, Saumya Shukla, Nidhi Anand, Chetan Parashar, and Nuzhat Husain. "Scar Endometriosis: Cytological Diagnosis." Journal of Nepal Medical Association 56, no. 209 (February 28, 2018): 550–52. http://dx.doi.org/10.31729/jnma.2940.
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Endometriosis occurring in a surgical scar is called incisional endometriosis. It is rare and can be diagnosed on the basis of detailed history, careful clinical examination and characteristic histology. An interesting case with immunocytological (ICC) confirmation is being reported. A 28-year-old female presented with a mass over anterior abdominal wall, of 3 years duration. She had a past history of LSCS. On examination, the swelling was subcutaneous, measures 3x2cm was firm in consistency and located close to the previous incisional scar. Fine needle aspiration cytology was performed and the smears were moderately cellular and showed monolayered sheets of epithelial cells and stromal fragments. A cell block was also prepared that revealed few glands lined by tall columnar epithelium, surrounded by loose stroma. Immunohistochemistry panel comprising of CK 7 and CD 10 was performed, which were positive in glandular and stromal component respectively.
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Chavarkar, Sneha P., Rajiv Rao, Akanksha Pandey, and Shirish P. Khatu. "Scar endometriosis: pre-operative diagnosis by fine needle aspiration cytology." International Journal of Research in Medical Sciences 7, no. 7 (June 28, 2019): 2862. http://dx.doi.org/10.18203/2320-6012.ijrms20192937.
Full textAbstract:
Scar endometriosis is a rare entity commonly observed after obstetrical and gynaecological procedures. The diagnosis is often delayed due to the non-specific nature of symptoms. Detailed clinical history of cyclical pain, location in proximity to a surgical scar and a suspicion of this rare entity in women of childbearing age are key to preoperative diagnosis. This is a case of a patient who presented with a troublesome scar after Caesarean section. On Fine needle aspiration cytology (FNAC) a diagnosis of scar endometriosis was provided which was further confirmed on histopathology. Herein we discuss the cytomorphological features of this rare entity and also emphasize the importance of its diagnosis on FNAC which is a rapid and cost-effective method.
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Vandemergel, X. "Solitary Intrathyroid Metastasis Occurring 23 Years after Resection of Renal Cell Carcinoma." Case Reports in Endocrinology 2021 (September 4, 2021): 1–3. http://dx.doi.org/10.1155/2021/2735256.
Full textAbstract:
A case of solitary intrathyroid metastasis is described in a 60-year-old male patient. He had a history of renal cell carcinoma classified as T1b resected 23 years earlier. A mass was palpable in the right thyroid lobe. Ultrasound showed a hypoechoic polylobular nodule with intense vascularisation in the right lobe. Fine needle aspiration cytology was normal, but thyroidectomy was performed due to mass enlargement, the ultrasound pattern, and the oncological history. Histological examination revealed the presence of an intrathyroid metastasis of renal cell carcinoma. The bone scan and thoracoabdominal CT scan were normal. Postoperative care was uneventful.
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Zhao, Ling-Ping, Gao-Lin Wu, and Zhi-Hua Shi. "Post-fire species recruitment in a semiarid perennial steppe on the Loess Plateau." Australian Journal of Botany 61, no. 1 (2013): 29. http://dx.doi.org/10.1071/bt12186.
Full textAbstract:
Offspring recruitment is an important part of population dynamics, as well as for plant-community structure and succession. One generality regarding grasses and fire is that clonal grasses tolerate fire extremely well and in most cases reach their maximum production in the immediate post-fire years. One qualification to this statement is that post-fire offspring, recruitment mode is very important. However, respective data are scare in the semiarid perennial steppe. We studied the relative importance of asexual v. sexual recruitment in the post-fire recovery in semiarid steppe on the Loess Plateau of north-western China. We observed differences in regeneration strategy after different times post-fire (burnt in 2008, burnt in 1999, and no fire history for at least 30 years). Results showed that fire significantly increased offspring recruitment numbers, but not species richness. The increase of asexual recruitment after a fire made a major contribution to the increase of total offspring number. Meanwhile, there was no significant difference for the ratio of asexual to sexual recruitment among sites with different times since fire. The asexual to sexual recruitment ratio was significantly different for different species, with some species not recruiting offspring via sexual recruitment. Our results indicated that seedling recruitment contributed little to post-fire recovery of the perennial-steppe community. Lack of sexual recruitment is not related to fire management but to inherent traits of the occurring plants.