scholarly journals Over 16,000 Years of Fire Frequency Determined from AMS Radiocarbon Dating of Soil Charcoal in an Alluvial Fan at Bear Flat, Northeastern British Columbia

Radiocarbon ◽  
2006 ◽  
Vol 48 (3) ◽  
pp. 435-450 ◽  
Author(s):  
A J Timothy Jull ◽  
Marten Geertsema
Keyword(s):  
British Columbia ◽  
Radiocarbon Dating ◽  
Large Scale ◽  
Fire Frequency ◽  
Alluvial Fan ◽  
Before Present ◽  
Ams Radiocarbon Dating ◽  
Soil Charcoal ◽  
Large Fires ◽  
Millennial Time Scale

We present results of radiocarbon dating of charcoal from paleosols and buried charcoal horizons in a unique sequence, which potentially records the last 36,000 yr, from a fan at Bear Flat, British Columbia (BC) (56°16'51’N, 121°13'39”W). Evidence for forest-fire charcoal is found over the last 13,500 ± 110 14C yr before present (BP) or 16,250 ± 700 cal BP. The study area is located east of the Rocky Mountains in an area that was ice-free at least 13,970 ± 170 14C yr BP (17,450–16,150 cal BP) ago. The latest evidence of fire is during the Medieval Warm Period (MWP). The charcoal ages show a periodicity in large fires on a millennial scale through the Holocene—an average of 4 fires per thousand years. Higher fire frequencies are observed between 2200 to 2800 cal BP, ∼5500 and ∼6000 cal BP, ∼7500 to 8200 cal BP, and 9000 to 10,000 cal BP. These intervals also appear to be times of above-average aggradation of the fan. We conclude that fire frequency is related to large-scale climatic events on a millennial time scale.

11 000 years of fire history and climate in the mountain hemlock rain forests of southwestern British Columbia based on sedimentary charcoal

2003 ◽  
Vol 33 (2) ◽  
pp. 292-312 ◽  
Author(s):  
Douglas J Hallett ◽  
Dana S Lepofsky ◽  
Rolf W Mathewes ◽  
Ken P Lertzman
Keyword(s):  
British Columbia ◽  
Lake Sediment ◽  
Fire History ◽  
Fire Regime ◽  
Fire Frequency ◽  
Summer Drought ◽  
Rain Forests ◽  
Independent Evidence ◽  
The Holocene ◽  
Soil Charcoal

Little is known about the role of fire in the mountain hemlock (Tsuga mertensiana (Bong.) Carrière) rain forests of southern British Columbia. High-resolution analysis of macroscopic charcoal from lake sediment cores, along with 102 accelerator mass spectrometry (AMS) ages on soil charcoal, was used to reconstruct the long-term fire history around two subalpine lakes in the southern Coast and North Cascade Mountains. AMS ages on soil charcoal provide independent evidence of local fire around a lake and support the interpretation of peaks in lake sediment charcoal as distinct fire events during the Holocene. Local fires are rare, with intervals ranging from centuries to several millennia at some sites. Overall fire frequency varied continuously throughout the Holocene, suggesting that fire regimes are linked to climate via large-scale atmospheric circulation patterns. Fires were frequent between 11 000 and 8800 calendar years BP during the warm and dry early Holocene. The onset of humid conditions in the mid-Holocene, as rain forest taxa established in the region, produced a variable fire period until 3500 calendar years BP. A synchronous decrease in fire frequency from 3500 to 2400 calendar years BP corresponds to Neoglacial advances in the region and cool humid climate. A return of frequent fire between 2400 and 1300 calendar years BP suggests that prolonged summer drought occurred more often during this interval, which we name the Fraser Valley Fire Period. The present-day fire regime was established after 1300 calendar years BP.

Wildfires in the southern Canadian Rocky Mountains and their relationship to mid-tropospheric anomalies

1993 ◽  
Vol 23 (6) ◽  
pp. 1213-1222 ◽  
Author(s):  
E.A. Johnson ◽  
D.R. Wowchuk
Keyword(s):  
North America ◽  
Rocky Mountains ◽  
Large Scale ◽  
Fire Frequency ◽  
Fuel Moisture ◽  
Large Fire ◽  
Canadian Rocky Mountains ◽  
Area Burned ◽  
Upper Level ◽  
Moisture Conditions

In this paper we present evidence for a large-scale (synoptic-scale) meteorological mechanism controlling the fire frequency in the southern Canadian Rocky Mountains. This large-scale control may explain the similarity in average fire frequencies and timing of change in average fire frequencies for the southern Canadian Rocky Mountains. Over the last 86 years the size distribution of fires (annual area burned) in the southern Canadian Rockies was distinctly bimodal, with a separation between small- and large-fire years at approximately 10–25 ha annual area burned. During the last 35 years, large-fire years had significantly lower fuel moisture conditions and many mid-tropospheric surface-blocking events (high-pressure upper level ridges) during July and August (the period of greatest fire activity). Small-fire years in this period exhibited significantly higher fuel moisture conditions and fewer persistent mid-tropospheric surface-blocking events during July and August. Mid-tropospheric surface-blocking events during large-fire years were teleconnected (spatially and temporally correlated in 50 kPa heights) to upper level troughs in the North Pacific and eastern North America. This relationship takes the form of the positive mode of the Pacific North America pattern.

AMS Radiocarbon Dating of the Type Plainview and Firstview (Paleoindian) Assemblages: The Agony and the Ecstasy

1999 ◽  
Vol 64 (3) ◽  
pp. 444-454 ◽  
Author(s):  
Vance T. Holliday ◽  
Eileen Johnson ◽  
Thomas W. Stafford
Keyword(s):  
Amino Acids ◽  
Great Plains ◽  
Radiocarbon Dating ◽  
Southern Plains ◽  
Ams Radiocarbon Dating ◽  
Tight Cluster ◽  
Bison Antiquus

Plainview and Firstview are two of the principal post-Folsom Paleoindian artifact assemblages on the Great Plains, but good radiometric age control for these artifact styles is relatively poor, due in part to lack of reliable age control on the type collections. This study reports the results of AMS-radiocarbon dating of specific amino acids from Bison antiquus bone associated with the type Plainview and Firstview assemblages from the Plainview and Olsen-Chubbuck sites, respectively. Seven samples of bone and teeth from Plainview produced a surprisingly wide array of ages. As a result, the age of the bone bed and the type Plainview collection remain uncertain, but it is most likely ≥ 10,000 B.P. (but late or post-Folsom) given the dating and stratigraphic relationships at Plainview and other sites. Seven samples of bone from Olsen-Chubbuck yielded a tight cluster of ages averaging ca 9400 B.P., fitting well with other dated Firstview features on the Southern Plains. These results show that much better age control from more sites is needed in order to understand the Paleoindian record. AMS-radiocarbon dating of specific amino acids from bone has revolutionized such issues of chronology in archaeology, but like any other method, it can provide confusing results and must be used in conjunction with other chronometric data.

Calibrated Radiocarbon Dating at Keatley Creek: The Chronology of Occupation at a Complex Hunter-Gatherer Village

2003 ◽  
Vol 68 (4) ◽  
pp. 719-735 ◽  
Author(s):  
William C. Prentiss ◽  
Michael Lenert ◽  
Thomas A. Foor ◽  
Nathan B. Goodale ◽  
Trinity Schlegel
Keyword(s):  
British Columbia ◽  
Radiocarbon Dating ◽  
Climatic Factors ◽  
Climatic Warming ◽  
Radiocarbon Dates ◽  
Population Aggregation ◽  
Selective Environment

This paper provides an analysis of radiocarbon dates acquired during earlier and recent field seasons at the Keatley Creek site, southern British Columbia. Results indicate that early occupations predating 1900 cal. B.P. occurred, but were not likely associated with population aggregation and large housepits. The aggregated village appears to have emerged by approximately 1700 cal. B.P. and was abandoned at approximately 800 cal. B.P. A break in the occupational sequence is recognized at 1450-1350 cal. B.P. and one other short break may have occurred shortly after 1250 cal. B.P. Peak socioeconomic complexity appears to have been achieved between 1350 and 800 cal B.P. Climatic warming may have provided a selective environment favoring population aggregation and intensification during this time. The final abandonment of the Keatley Creek village appears to have been part of a regional phenomenon suggesting the possibility that climatic factors were important in this case as well.

Using polycyclic aromatic hydrocarbons to determine post-wildfire contamination and sediment sources in a large watershed in central British Columbia, Canada

2021 ◽  
Author(s):  
Kristen Kieta ◽  
Philip Owens ◽  
Ellen Petticrew
Keyword(s):  
British Columbia ◽  
Magnetic Susceptibility ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Large Scale ◽  
Sediment Samples ◽  
Burned Areas ◽  
Total Pahs ◽  
Polycyclic Aromatic ◽  
The Impact

<p>The Nechako River Basin (NRB) in central British Columbia is a large (52,000 km<sup>2</sup>), regulated basin that supports populations of sockeye and chinook salmon and the endangered Nechako white sturgeon. These important species are experiencing population declines and one potential cause of this decline is excess sediment, which can clog their spawning habitat and reduce juvenile success. This excess sediment is likely the product of a combination of factors, the most visible being the significant land cover changes that have occurred in the basin, which includes pressure from forestry and agriculture, the Mountain Pine Beetle epidemic, and large-scale wildfires in 2018. Focusing specifically on the impact of the 2018 wildfires on sediment transport from upland burned areas to adjacent waterways, this research aimed to determine the spatial and temporal contamination of tributaries and the mainstem of the Nechako River with polycyclic aromatic hydrocarbons (PAHs), which are produced during the combustion of organic matter and have been identified as toxic to aquatic organisms and to humans. Additionally, this study intended to determine if burned areas were a more significant contributor of sediment than unburned areas and better understand the utility of PAHs as a potential tracer. Source soil samples were collected in 2018 and 2020 from burned and unburned sites, and suspended sediment samples were collected throughout the ice-free period from 2018-2020 in three tributaries and three mainstem sites. All samples were analysed for PAHs, magnetic susceptibility, colour, and particle size. Results from the fall 2018 source samples show a significant difference in PAH concentrations between unburned and burned soils, and while concentrations of PAHs in source soils in 2020 were lower than in 2018, they were still elevated compared to unburned soils. Sediment samples showed that concentrations of total PAHs are higher in the mainstem sites than in the tributaries, with the greatest concentrations consistently found at the most downstream site on the mainstem of the Nechako River. Concentrations across sites were highest in samples taken during the spring snowmelt period in 2019, have decreased throughout the rest of the sampling period (2019-2020), and are well below sediment quality guidelines for total PAHs. In addition to determining the spatial and temporal extent of PAH contamination, this study also aims to use PAHs along with colour and measurements of magnetic susceptibility to trace sediments associated with the 2018 wildfires. The high cost of PAH analysis limits the number of samples that can be analysed and thus, these additional tracers will allow for the use of models such as MixSIAR that improve with a more robust number of samples. As large-scale megafires continue to burn across the globe, understanding their potential to contribute PAHs to local waterbodies and potentially be used as a tracer is as prescient as ever.</p>

A Model of Seawater Structure Near the West Coast of Vancouver Island, British Columbia

1963 ◽  
Vol 20 (4) ◽  
pp. 939-967 ◽  
Author(s):  
Robert K. Lane
Keyword(s):  
British Columbia ◽  
West Coast ◽  
Large Scale ◽  
Coastal Region ◽  
Vancouver Island ◽  
Structural Elements ◽  
The West ◽  
Characteristic Structure ◽  
Oceanographic Data ◽  
Vertical Sections

Oceanographic data collected in a line of stations extending seaward of the west coast of Vancouver Island, British Columbia, were reviewed and analyzed. On the basis of these data and the large-scale meteorological processes of wind, insolation, and precipitation, the characteristic structure of temperature and salinity in the coastal region was denned in five temporal stages throughout the year. These stages are presented as vertical sections along the line with characteristic ranges of values to be found in each of the structural elements.

Extending the Place Glacier mass-balance record to AD 1585, using tree rings and wood density

2011 ◽  
Vol 76 (3) ◽  
pp. 305-313 ◽  
Author(s):  
Lisa J. Wood ◽  
Dan J. Smith ◽  
Michael N. Demuth
Keyword(s):  
British Columbia ◽  
Mass Balance ◽  
Large Scale ◽  
Ring Width ◽  
Climate Forcing ◽  
Glacier Mass Balance ◽  
Increment Core ◽  
Engelmann Spruce ◽  
Circulation Indices ◽  
Forcing Mechanisms

AbstractRecognizing that climate influences both annual tree-ring growth and glacier mass balance, changes in the mass balance of Place Glacier, British Columbia, were documented from increment core records. Annually resolved ring-width (RW), maximum (MXD), and mean density (MD) chronologies were developed from Engelmann spruce and Douglas-fir trees sampled at sites within the surrounding region. A snowpack record dating to AD 1730 was reconstructed using a multivariate regression of spruce MD and fir RW chronologies. Spruce MXD and RW chronologies were used to reconstruct winter mass balance (Bw) for Place Glacier to AD 1585. Summer mass balance (Bs) was reconstructed using the RW chronology from spruce, and net balance was calculated from Bw and Bs. The reconstructions provide insight into the changes that snowpack and mass balance have undergone in the last 400 years, as well as identifying relationships to air temperature and circulation indices in southern British Columbia. These changes are consistent with other regional mass-balance reconstructions and indicate that the persistent weather systems characterizing large scale climate-forcing mechanisms play a significant glaciological role in this region. A comparison to dated moraine surfaces in the surrounding region substantiates that the mass-balance shifts recorded in the proxy data are evident in the response of glaciers throughout the region.

scholarly journals Origin identification of migratory pests (European Starling) using geochemical fingerprinting

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8962
Author(s):  
Upama Khatri-Chhetri ◽  
John G. Woods ◽  
Ian R. Walker ◽  
P. Jeff Curtis
Keyword(s):  
British Columbia ◽  
Trace Elements ◽  
Large Scale ◽  
Geographic Origin ◽  
Dairy Farms ◽  
European Starling ◽  
Northern Region ◽  
Stepwise Discriminant Analysis ◽  
Natal Origin ◽  
South Central

The European Starling (Sturnidae: Sturnus vulgaris L.) is an invasive bird in North America where it is an agricultural pest. In British Columbia (Canada), the starling population increases in orchards and vineyards in autumn, where they consume and damage ripening fruits. Starlings also cause damage in dairy farms and feedlots by consuming and contaminating food and spreading diseases. Damage can be partly mitigated by the use of scare devices, which can disperse flocks until they become habituated. Large-scale trapping and euthanizing before starlings move to fields and farms could be a practical means of preventing damage, but requires knowledge of natal origin. Within a small (20,831 km2), agriculturally significant portion of south-central British Columbia, the Okanagan-Similkameen region, we used 21 trace elements in bone tissue to discriminate the spatial distribution of juvenile starlings and to reveal the geographic origin of the problem birds in fall. Stepwise discriminant analysis of trace elements classified juveniles to their natal origin (minimum discrimination distance of 12 km) with 79% accuracy. In vineyards and orchards, the majority (55%) of problem birds derive from northern portions of the valley; and the remaining 45% of problem birds were a mixture of local and immigrant/unassigned birds. In contrast, problem birds in dairy farms and feedlots were largely immigrants/unassigned (89%) and 11% were local from northern region of the valley. Moreover, elemental signatures can separate starling populations in the Valley yielding a promising tool for identifying the geographic origin of these migratory birds.

Statistical Evaluation of a Large-Scale Fishing Experiment Designed to Test for a Genetic Effect of Size-Selective Fishing on British Columbia Pink Salmon (Oncorhynchus gorbuscha)

1992 ◽  
Vol 49 (7) ◽  
pp. 1294-1304 ◽  
Author(s):  
Murdoch K. McAllister ◽  
Randall M. Peterman ◽  
Darren M. Gillis
Keyword(s):  
British Columbia ◽  
Statistical Power ◽  
Large Scale ◽  
Pink Salmon ◽  
Genetic Effect ◽  
Oncorhynchus Gorbuscha ◽  
Causal Mechanism ◽  
Block Designs ◽  
Adult Size ◽  
Pink Salmon Oncorhynchus Gorbuscha

Since 1950, stocks of British Columbia pink salmon (Oncorhynchus gorbuscha) have shown up to a 34% decrease in mean adult body weight, causing significant reduction in economic value of commercial harvests. Previous research suggests that this trend is due to size-selective harvesting of large fish, but changes in oceanographic conditions are a plausible alternative. Corrective action by management agencies requires that the true causal mechanism be identified. We therefore examined several possible designs for a large-scale fishing experiment devised to test the size-selective fishing hypothesis. These designs would generate accurate and precise field estimates of the heritability (h2) of growth rate, which is important because it, in combination with the selection differential (D) caused by fishing, determines how rapidly body size changes. Monte Carlo simulations showed that block designs with three to six spatial replicates and relatively short durations generated high statistical power. For example, for h2 = 0.22, D = 0.25 kg, and four spatial replicates, an 8-yr experiment resulted in power = 0.87, which gave a SE < 0.10 for h2 = 0.22. We conclude that some experimental designs have good potential to test the possible effects of size-selective fishing on mean adult size of British Columbia pink salmon.

Absolute Dating of the Virje and Hlebine Sites

2021 ◽  
pp. 92-100
Author(s):  
Katarina Botić
Keyword(s):  
Environmental Change ◽  
Bayesian Model ◽  
Radiocarbon Dating ◽  
Iron Formation ◽  
Iron Production ◽  
Formation Processes ◽  
Residential Areas ◽  
Ams Radiocarbon Dating ◽  
Absolute Dating ◽  
Cool Conditions

In this chapter the results of AMS radiocarbon dating of 26 charcoal samples from four sites are discussed. The primary aim was to explore the scope of (dis)continuity of temporally and functionally interconnected types of sites (settlement and iron production workshop). A Bayesian model was created based on the acquired data from excavated sites with three sequences in the model determined. The results show great accordance with the archaeologically based data, with some exceptions that are most probably a result of modelling strategy used. Contemporaneity of all four sites is mostly attested with a possible and very short temporal hiatus around AD 600. Occupation of workshop and residential areas at that time or slightly after may have been linked to the globally attested environmental change during the Bond 1 event when dry and cool conditions prevailed and which could have had an impact on bog iron formation processes.

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