Holocene vegetation history of the boreal forest near Chibougamau, central Quebec

1992 ◽  
Vol 70 (7) ◽  
pp. 1364-1368 ◽  
Author(s):  
Silvina Garralla ◽  
K. Gajewski
Keyword(s):  
Boreal Forest ◽  
Pinus Banksiana ◽  
Vegetation History ◽  
Climatic Conditions ◽  
Betula Papyrifera ◽  
Long Distance ◽  
Pollen Diagram ◽  
Shrub Tundra ◽  
History Of ◽  
Open Forests

A pollen diagram from a small lake in the region of Chibougamau (49°41′N, 74°35′W; elevation 380 m), central Quebec, is divided into four pollen assemblage zones. Before 7600 BP the landscape was open shrub tundra and the pollen input to the lake was primarily from long-distance sources. Larix, and to a lesser extent Populus, were important colonizers of the newly deglaciated land, and Picea was also present. Betula papyrifera and Picea dominated the open forests between 7600 and 4700 BP. After 4700 BP the forest became more dense and the importance of Betula papyrifera suggests relatively warm and dry climatic conditions. Around 3900 BP Picea, Ericaceae, and Sphagnum increased in abundance at the expense of Betula, suggesting cooler, wetter conditions. Pinus banksiana increased during this period but was never very abundant. The modern boreal forest thus developed relatively late in this region and has been present for only the past 2000–3000 BP. Key words: paleoecology, Quebec, Holocene, boreal forest, Betula papyrifera, Picea.

Postglacial vegetation history of oak savanna in southern Ontario

1991 ◽  
Vol 69 (7) ◽  
pp. 1507-1519 ◽  
Author(s):  
J. M. Szeicz ◽  
G. M. MacDonald
Keyword(s):  
Tree Species ◽  
Pinus Banksiana ◽  
Vegetation History ◽  
Pinus Strobus ◽  
Climatic Conditions ◽  
Fossil Pollen ◽  
Oak Savanna ◽  
Early Date ◽  
Southern Ontario ◽  
History Of

Sizable areas of oak savanna were present in southern Ontario when the region was first settled by Europeans. The objective of this study was to reconstruct the vegetation history of oak savanna at a site in Ontario and to test the hypothesis that the savanna was created by Indian burning. The fossil pollen, plant macrofossil, and fossil charcoal records of the sediments of a small lake were used to reconstruct postglacial vegetation development in an area formerly occupied by oak savanna. The fossil record from the site extends from approximately 11 800 BP to the present. The initial vegetation around the lake was an open Picea woodland similar to that reported from other late glacial sites in southern Ontario. Pinus banksiana forest dominated the vegetation of the site between about 10 000 and 9000 BP. Pinus strobus replaced Pinus banksiana and remained the dominant tree species in the area until approximately 6000 BP. The persistence of Pinus strobus as the dominant tree species until 6000 BP is unique in southern Ontario. Between 6000 and 4000 BP the Pinus strobus forest was replaced by oak savanna. Oak savanna occupied the area until land clearance by Europeans at approximately A.D. 1850. The early date at which oak savanna developed makes it unlikely that Indian burning was the cause of savanna formation. Determining the cause of the late persistence of Pinus strobus-dominated vegetation and its replacement by oak savanna is difficult. It is possible that the late persistence of Pinus strobus in the study area is related to dry climatic conditions during the mid-Holocene (~8000 to 6000 BP). The establishment of oak savanna may have been caused by the transition to moister climatic conditions in the later half of the Holocene. The particularly dry and well-drained substrates associated with oak savanna may have restricted occupation of these regions by more mesic tree species and maintained herb and graminoid dominated openings by promoting natural fires. Key words: Palaeoecology, fossil pollen, Holocene, oak savanna, southern Ontario.

Modern Pollen Assemblages and Vegetational History of the Moraines of the Klutlan Glacier and Its Surroundings, Yukon Territory, Canada

1980 ◽  
Vol 14 (1) ◽  
pp. 101-129 ◽  
Author(s):  
H. J. B. Birks
Keyword(s):  
Picea Glauca ◽  
Yukon Territory ◽  
Canonical Variate ◽  
Pollen Diagram ◽  
Modern Pollen ◽  
Canonical Variates ◽  
Shrub Tundra ◽  
History Of ◽  
Shepherdia Canadensis ◽  
Modern Pollen Assemblages

AbstractModern pollen assemblages have been studied from surficial lake muds and moss polsters collected from five vegetated ice-cored moraines of the Klutlan Glacier. The youngest vegetated moraine (K-II) is characterized by high pollen values for Salix and Hedysarum, K-III by high Salix and Shepherdia canadensis and low Hedysarum and Picea, K-IV by high Betula, Salix, and Shepherdia, and K-V and the Harris Creek moraine (HCM) by high Picea. Variations are summarized by canonical variates analysis. A percentage pollen diagram from Gull Lake on the upland east of the glacier records vegetational development since the deposition of the White River volcanic ash 1220 14C yr ago. An initial species-rich treeless vegetation was replaced by birch-alder-willow shrub-tundra, and this by open Picea glauca forest similar to present vegetation around the lake. Sites on HCM show two basic stratigraphies. Triangle Lake reflects vegetational succession from Salix-Shepherdia canadensis scrub similar to that on K-III today, through open Picea woodland of K-IV type, to closed Picea forests of K-V and HCM. Heart Lake and Cotton Pond reflect vegetational development following melting of ice underlying the spruce forests of HCM. These two types are summarized by positioning the fossil spectra on the first two canonical variate axes of the modern surface spectra.

A palynological study of postglacial vegetation changes in the University Research Forest, southwestern British Columbia

1973 ◽  
Vol 51 (11) ◽  
pp. 2085-2103 ◽  
Author(s):  
Rolf W. Mathewes
Keyword(s):  
British Columbia ◽  
Pinus Contorta ◽  
Vegetation Change ◽  
Vegetation History ◽  
Sediment Cores ◽  
Silty Clay ◽  
Pollen Diagram ◽  
History Of ◽  
Palynological Study ◽  
The University

The postglacial vegetation history of the University of British Columbia Research Forest was investigated using percentage and absolute pollen analysis, macrofossil analysis, and radiocarbon dating. A marine silty clay deposit records the oldest (12 690 ± 190 years before present (B.P.)) assemblage of terrestrial plant remains so far recovered from the postglacial of south-coastal British Columbia. Lodge-pole pine (Pinus contorta) dominated this early vegetation, although some Abies, Picea, Alnus, and herbs were also present. Sediment cores from two lakes were also studied. The older is Marion Lake, where five pollen assemblage zones are recognized, beginning with a previously undescribed assemblage of Pinus contorta, Salix, and Shepherdia in clay older than 12 350 ± 190 B.P. The pollen diagram from Surprise Lake (11 230 ± 230 B.P.) is divided into three pollen zones which show the same major trends of vegetation change as the Marion Lake diagram.The first report of the postglacial vegetation history of cedar (Thuja and perhaps Chamaecyparis) in southwestern British Columbia is presented from pollen and macrofossil analyses.At about 10 500 B.P. in both lakes, pollen of Douglas fir (Pseudotsuga menziesii) began a rapid increase, probably in response to climatic amelioration. The palynological evidence, supported by well-preserved bryophyte subfossils, suggests that humid coastal conditions have prevailed in the study area since about 10 500 B.P., with virtually no evidence for a classical Hypsithermal interval between 8500 B.P. and 3000 B.P.

A 12,000-Year History of Vegetation and Climate for Cape Cod, Massachusetts

1985 ◽  
Vol 23 (3) ◽  
pp. 301-312 ◽  
Author(s):  
Marjorie Green Winkler
Keyword(s):  
Pinus Banksiana ◽  
Vegetation History ◽  
Sediment Cores ◽  
Pinus Strobus ◽  
Cape Cod ◽  
Pine Barrens ◽  
Conifer Forest ◽  
Climate History ◽  
History Of ◽  
Vegetation And Climate

Pollen and charcoal analysis of radiocarbon-dated sediment cores from Duck Pond in the Cape Cod National Seashore provide a continuous 12,000-yr vegetation and climate history of outer Cape Cod. A Picea-Hudsonia parkland and then a Picea-Pinus banksiana-Alnus crispa boreal forest association grew near the site between 12,000 and 10,000 yr B.P. This vegetation was replaced by a northern conifer forest of Pinus strobus-P. banksiana, and, subsequently, by a more mesophytic forest (Pinus strobus, Tsuga, Quercus, Fagus, Acer, Ulmus, Fraxinus, Ostrya) as the climate became warmer and wetter by 9500 yr B.P. By 9000 yr B.P. a Pinus rigida-Quercus association dominated the landscape. High charcoal frequencies from this and subsequent levels suggest that the pine barrens association developed during a warmer and drier climate that lasted from 9000 to about 5000 yr B.P. Increased percentages of Pinus strobus pollen indicate a return to moister and cooler conditions by about 3500 yr B.P. A doubled sedimentation rate, increased charcoal, and increased herb pollen suggest land disturbance near the pond before European settlement. These results suggest a rapid warming in the northeast in the early Holocene and support a hypothesis of a rapid sea level rise at that time. Comparison of the pollen results from Duck Pond with those from Rogers Lake, Connecticut, illustrates the importance of edaphic factors in determining the disturbance frequency and vegetation history of an area.

Late Quaternary vegetation history of Kettlehole Pond, southwestern Yukon

1988 ◽  
Vol 18 (10) ◽  
pp. 1270-1279 ◽  
Author(s):  
Les C. Cwynar
Keyword(s):  
Vegetation History ◽  
Late Quaternary ◽  
Initial Period ◽  
Forest Tree ◽  
Published Data ◽  
Vegetation Changes ◽  
Pollen Diagram ◽  
Mesic Forest ◽  
Effective Moisture ◽  
History Of

A pollen diagram with a detailed chronology reveals Late-Pleistocene and Holocene vegetation changes which, in combination with previously published data, provide information on regional vegetation changes in the western boreal forest of the southwestern Yukon. A Populus woodland with an understory of Shepherdiacanadensis and extensive open areas dominated by Artemisia occurred from 11 030 to 9250 BP. Juniperus populations expanded at 9700 BP and then more-mesic forest communities developed when Piceaglauca populations increased at 9250 BP and Populus declined. At 6100 BP there is a remarkable shift from Piceaglauca woodland with Juniperus to a mixed spruce forest in which P. mariana was the dominant species. At 4100 BP conditions altered to favour P. glauca which expanded at the expense of P. mariana, and Juniperus again became important in the vegetation. By 1900 BP Pinuscontorta had become a dominant tree as P. mariana declined, the latter eventually disappearing from the local vegetation. There is no evidence that grasslands were more extensive in the early Holocene, as has been hypothesized for the southwestern Yukon. The vegetation sequence implies an initial period of aridity from 11 030 to 9250 BP, when summer warmth was probably greater than that of the modern climate, a period of increased effective moisture between 9250 and 6100 BP, when Piceaglauca was abundant, even greater effective moisture between 6100 and 4100 BP, when Piceamariana was the dominant forest tree, and then a prolonged period of increasing aridity beginning at 4100 BP and culminating in the development of the modern semi-arid climate.

A 14,000 year peatland record of environmental change in the southern Gutland region, Luxembourg

The Holocene ◽  
2021 ◽  
pp. 095968362199464
Author(s):  
Karsten Schittek ◽  
Lelaina Teichert ◽  
Katrin Geiger ◽  
Klaus-Holger Knorr ◽  
Simone Schneider
Keyword(s):  
Bronze Age ◽  
Environmental History ◽  
Middle Ages ◽  
Late Pleistocene ◽  
Vegetation History ◽  
Climatic Conditions ◽  
Peat Deposits ◽  
Organic Sediment ◽  
Species Abundances ◽  
History Of

A Late Pleistocene/Holocene paleoenvironmental record was obtained from the Rouer peatland (5°54′E, 49°45′N; 270 m a.s.l.), located in the Gutland area of southern Luxembourg. A total of six sediment samples were AMS radiocarbon-dated to obtain an age-depth model. XRF analyses and analyses of geochemical proxies of organic matter (TOC, TN, δ13C, δ15N) were conducted to identify major paleoenvironmental changes in the record. Pollen analysis reveals insights into the vegetation history throughout the last 14,000 cal. yr BP. The record offers unique insights into the evolution of local organic sediment/peat accumulation, as well as into the environmental history of the Gutland region and beyond. The accumulation of organic sediment and peat started at about 13,800 cal. yr BP before present. Until about 6000 cal. yr BP, periods of apparently stable climatic conditions had been interrupted repeatedly by pronounced episodes with increased input of minerogenic matter into the peat matrix (12,700–11,800 cal. yr BP; 11,500–11,300 cal. yr BP; 11,100–10,800 cal. yr BP; 9300 cal. yr BP; 8200 cal. yr BP), indicated by sudden increases of Ti/coh values. After 6000 cal. yr BP, environmental conditions stabilized. Between 4200 and 2800 cal. yr BP, during the Bronze Age, changes in the pollen spectrum indicate an increasing clearance of woodlands. Since the Roman period, an ongoing intensification of grassland farming and agriculture is evidenced. Lowest tree species abundances are witnessed during the Middle Ages. The Modern Era is characterized by enhanced sediment input due to soil erosion. In short, this record complements the Late Pleistocene/Holocene climatic history of the Gutland area and demonstrates that fen peat deposits can be valuable high-resolution paleoclimate archives.

scholarly journals Late Quaternary Pollen Records and Vegetation History of the Southwest Yukon Territory: A Review

2007 ◽  
Vol 45 (2) ◽  
pp. 175-193 ◽  
Author(s):  
Xia-Cheng Wang ◽  
Marie-Anne Geurts
Keyword(s):  
Vegetation History ◽  
Late Quaternary ◽  
Late Glacial ◽  
Yukon Territory ◽  
Circulation System ◽  
Spruce Forest ◽  
Migration Routes ◽  
Shrub Tundra ◽  
History Of ◽  
Pollen Records

ABSTRACTThis paper is a summary of all known late Quaternary palynostratigraphic records from the southwest Yukon Territory. Thirty two pollen sites available by the end of 1988 are reviewed. Most pollen records in the region are of Holocene age. During the late-glacial to early Holocene, the southwest Yukon supported a herb-dominated tundra vegetation which was replaced by a birch-dominated shrub-tundra at about 10,000 yr BP. Spruce invaded the area between 9000 and 8600 yr BP at different localities, and a southward time transgression is visible in the Aishihik Basin. The current regional vegetation has been stable since 7600-8000 yr BP when dense spruce forest and/or spruce forest-tundra was established in most localities. In the Snag area, however, dense spruce forest developed only around 5700 yr BP, which is about 2000 years later than in the Aishihik Basin. The exotic pine pollen records in the region exhibit an interesting pattern, suggesting a frequent shift of the atmospheric circulation system. Anomalous records of alder pollen from the Aishihik Basin and adjacent regions suggest that alder has never been widespread in these areas due to aridity, and alder pollen is greatly overrepresented in pollen spectra. Spruce arrival dates suggest that further investigations in the Tintina Valley, Yukon River Valley, and Car-macks region might provide useful information concerning the spruce migration routes.

scholarly journals Contribution to Early Holocene vegetation and climate history of Eastern Orinoco Llanos, Venezuela, from a paleoecological record of a Mauritia L.f. swamp

2011 ◽  
Vol 41 (4) ◽  
pp. 513-520 ◽  
Author(s):  
Alejandra Leal ◽  
Tibisay Perez ◽  
Bibiana Bilbao
Keyword(s):  
Amazon Basin ◽  
Vegetation History ◽  
Climatic Conditions ◽  
Early Holocene ◽  
Pollen Record ◽  
Climate History ◽  
Palynological Analysis ◽  
Regional Trends ◽  
Pollen Types ◽  
History Of

A palynological analysis of an organic paleosol found at 150-125 cm depth in a Mauritia swamp from the Eastern Orinoco Llanos is presented. The 25 cm pollen record summarizes the vegetation history during the Early Holocene, from 10,225 to 7,800 calendar yr BP. The vegetation was characterized by a Poaceae marsh, where Asteraceae, Melastomataceae, Schefflera-type and Phyllanthus were the most abundant shrubs and trees. Pollen-types richness was lower than that recorded today in similar environments, and Mauritia pollen was absent. Results suggest that climate was as humid as present during the beginning of the Holocene, with a decreasing trend in humidity from around 8,000-7,000 yr BP, in coincidence with the beginning of the "Early-Mid-Holocene Dryness" that affected deeply the Amazon Basin and neighboring areas. Dry climatic conditions could have existed in the study site until the Mid-Late Holocene when a Mauritia swamp developed, and humid conditions similar to present established. Main climate phases inferred in our study site fit well with regional trends recorded in other places located north Amazon Basin. However, conclusions are still limited by the lack of additional Quaternary records in the Orinoco Llanos area, avoiding regional correlations.

A 14,000-Year Pollen Record from Sithylemenkat Lake, North-Central Alaska

1990 ◽  
Vol 33 (3) ◽  
pp. 400-404 ◽  
Author(s):  
Patricia M. Anderson ◽  
Richard E. Reanier ◽  
Linda B. Brubaker
Keyword(s):  
Boreal Forest ◽  
Sediment Core ◽  
Pollen Analysis ◽  
Picea Glauca ◽  
Pollen Record ◽  
North Central ◽  
The Holocene ◽  
Unusual Combination ◽  
Shrub Tundra ◽  
History Of

AbstractPollen analysis of a 14,000-yr-old sediment core from Sithylemenkat Lake provides the first Holocene vegetational history for the Kanuti Flats of north-central Alaska. Basal samples contain a curious and unusual combination of tundra and boreal taxa. Pollen assemblages dating from 13,500 to 9000 yr B.P. are more typical of southern Brooks Range sites and indicate the presence ofBetulashrub tundra with increasedPopulusca. 10,000 to 9000 yr B.P.Picea glaucaappeared ca. 9000 yr B.P. andAlnusca. 8000 yr B.P.P. glaucapopulations declined between 7800 and 5000 yr B.P. with a subsequent reforestation byP. marianaandP. glauca. This pattern is seen at other sites in northeastern Alaska and suggests that the Holocene history of boreal forest is more complex than thought previously.

scholarly journals Vegetation history of Central Chukotka deduced from permafrost paleoenvironmental records of the El'gygytgyn Impact Crater

2012 ◽  
Vol 8 (2) ◽  
pp. 1409-1441 ◽  
Author(s):  
A. A. Andreev ◽  
E. Morozova ◽  
G. Fedorov ◽  
L. Schirrmeister ◽  
A. A. Bobrov ◽  
...  
Keyword(s):  
Impact Crater ◽  
Environmental Changes ◽  
Vegetation History ◽  
Lacustrine Sediments ◽  
Plant Macrofossils ◽  
Early Holocene ◽  
Shrub Tundra ◽  
Dwarf Birch ◽  
History Of ◽  
Palynological Study

Abstract. Frozen sediments from three cores bored in permafrost surrounding of the El'gygytgyn Impact Crater Lake have been studied for pollen, non-pollen palynomorphs, plant macrofossils, and rhizopods. The palynological study of the cores contributes to a higher resolution of time intervals presented in a poor temporal resolution in the lacustrine sediments; namely the Allerød and succeeding periods. Moreover, permafrost records better reflect local environmental changes, thus, allowing more reliable reconstruction of the local paleoenvironments. The new data confirm that shrub tundra with dwarf birch, shrub alder and willow dominated in the lake surroundings during the Allerød warming. Younger Dryas pollen assemblages reflect abrupt changes to grass-sedge-herb dominated environments reflecting significant climate deterioration. Low shrub tundra with dwarf birch and willow dominate the lake vicinity at the onset of the Holocene. The founds of larch seeds indicate its local presence around 11 000 cal. yr BP and, thus a northward shift of treeline by about 100 km during the early Holocene thermal optimum. Forest tundra with larch and shrub alder stands grew in the area during the early Holocene. After ca. 3500 cal. yr BP similar-to-modern plant communities became common in the lake vicinity.

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