Postglacial history of a cedar swamp in southeastern Connecticut

1991 ◽  
Vol 6 (1) ◽  
Author(s):  
RobertM. Thorson ◽  
RobertS. Webb
Keyword(s):  
Postglacial History ◽  
History Of ◽  
Cedar Swamp

Palynology and Paleoecology of Postglacial Sediments from the Lower Fraser River Canyon of British Columbia

1975 ◽  
Vol 12 (5) ◽  
pp. 745-756 ◽  
Author(s):  
R. W. Mathewes ◽  
G. E. Rouse
Keyword(s):  
Tsuga Heterophylla ◽  
Climatic Conditions ◽  
Douglas Fir ◽  
Fraser River ◽  
Pollen Assemblage ◽  
Glacial Ice ◽  
Transitional Area ◽  
Postglacial History ◽  
History Of Vegetation ◽  
History Of

The postglacial history of vegetation in the Yale area of the lower Fraser River Canyon is described from sediments of two lakes using percentage pollen analysis supplemented with macrofossil evidence and radiocarbon dating. Deposition of postglacial sediments, ranging from basal clays to gyttjas, began about 11 500 y B.P. Three distinct pollen assemblage zones are distinguished, reflecting in part the main climatic conditions for the intervals. The oldest zone, with high percentages of pine (Pinus) and alder (Alnus) pollen, suggests cool and moist conditions following withdrawal of glacial ice. This is followed by marked increases in Douglas-fir (Pseudotsuga), grasses and other nonarboreal pollen, suggesting in part, warmer and drier conditions. The third zone, ranging from about the Mt. Mazama ash at 6600 y B.P. to the present, is marked by high alder and Douglas-fir, and increasing cedar (Thuja-Chamaecyparis type), western hemlock (Tsuga heterophylla), fir (Abies) and birch; an assemblage indicating a return to wetter conditions. This sequence contrasts with previously described successions that recognized the classical Hypsithermal in adjacent areas. The sequence of inferred vegetational changes, although similar to those described for the Haney area to the west, suggests that the Yale area has been a biogeoclimatically transitional area for much of postglacial time.

Postglacial history of lakes Ladoga and Onega according to diatom analyses of bottom sediments

1969 ◽  
Vol 17 (1) ◽  
pp. 371-378
Author(s):  
N. N. Davidova
Keyword(s):  
Bottom Sediments ◽  
Postglacial History ◽  
History Of

Postglacial history of subalpine forests, Olympic Peninsula, Washington, USA

The Holocene ◽  
2001 ◽  
Vol 11 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Daniel G. Gavin ◽  
Jason S. Mclachlan ◽  
Linda B. Brubaker ◽  
Kyle A. Young
Keyword(s):  
Olympic Peninsula ◽  
Subalpine Forests ◽  
Postglacial History ◽  
History Of

Postglacial paleoecological history of a cedar swamp, manitoulin island, Ontario, Canada

1984 ◽  
Vol 45 (3-4) ◽  
pp. 301-345 ◽  
Author(s):  
Barry G. Warner ◽  
Richard J. Hebda ◽  
Brenda J. Hann
Keyword(s):  
History Of ◽  
Cedar Swamp

Geographic variation in the monoterpene composition of Sitka spruce cortical oleoresin

1980 ◽  
Vol 10 (4) ◽  
pp. 458-463 ◽  
Author(s):  
G. I. Forrest
Keyword(s):  
Geographic Variation ◽  
Systems Analysis ◽  
Sitka Spruce ◽  
Vancouver Island ◽  
Postglacial History ◽  
History Of ◽  
The Individual ◽  
High Degree ◽  
Monoterpene Composition ◽  
Percentage Data

The monoterpene composition of the cortical oleoresin from main stems and from branch apical shoots was measured in young trees of Piceasitchensis (Bong.) Carr. grown in Britain from seed collected from eight northwestern American origins. There was a high degree of variation within origins in both resin systems. Analysis of the individual monoterpene percentage data and of the representation of monoterpene pattern types showed that the Vancouver Island origin was the most distinct. There was a cline in several monoterpene characters, notably a decrease in β-phellandrene and an increase in 3-carene both by itself and also accompanied by limonene, from Alaska to north Washington, but the Washington and Oregon origins showed no geographical trends. The results are discussed in the context of the postglacial history of the species.

A postglacial history of vegetation and bog formation at Point Escuminac, New Brunswick

1991 ◽  
Vol 28 (10) ◽  
pp. 1572-1582 ◽  
Author(s):  
Barry G. Warner ◽  
Kimmo Tolonen ◽  
Mirjami Tolonen
Keyword(s):  
New Brunswick ◽  
Radiocarbon Dating ◽  
Coniferous Forests ◽  
Postglacial History ◽  
History Of Vegetation ◽  
Ombrotrophic Bog ◽  
History Of ◽  
Northern Edge ◽  
Woodland Communities

Radiocarbon dating and analyses of fossils contained in peat cliffs establish the history of peatland formation and development at the northern edge of Point Escuminac, New Brunswick. A 532 cm radiocarbon-dated mineral sediment and peat sequence, the oldest of four sections studied, yielded pollen and macrofossils that record bog development from 11 000 BP. The earliest landscape was open Juniperus shrubland. Picea was the first tree to move into the area, forming woodland communities by 10 200 BP and closed coniferous forests with Abies by 9200 BP. An early counterpart of the modern Acadian forests was in place by 6500 BP and was fully developed by 2900 BP when Fagus spread through the area. Shallow freshwater, open wetland communities acted as nuclei for the development of fen near the centre of the peninsula. Transformation into an ombrotrophic bog started around 6500 BP and was completed by 4700 BP, after which time the bog spread laterally by paludification onto higher parts of the peninsula.

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