Evidence of a physiological basis for the boreal-deciduous forest ecotone in North America

Vegetatio ◽  
1989 ◽  
Vol 82 (1) ◽  
Author(s):  
LelaniL. Arris ◽  
PeterS. Eagleson
Keyword(s):  
North America ◽  
Deciduous Forest ◽  
Physiological Basis ◽  
Forest Ecotone

A classification of the deciduous forest of eastern North America

Vegetatio ◽  
1989 ◽  
Vol 80 (2) ◽  
pp. 167-181 ◽  
Author(s):  
Carl D. Monk ◽  
Donald W. Imm ◽  
Robert L. Potter ◽  
Geoffrey G. Parker
Keyword(s):  
North America ◽  
Deciduous Forest ◽  
Eastern North America

The biology of Canadian weeds. 130. Solidago nemoralis Ait.

2004 ◽  
Vol 84 (4) ◽  
pp. 1221-1233 ◽  
Author(s):  
Jerry G. Chmielewski ◽  
John C. Semple
Keyword(s):  
United States ◽  
North America ◽  
Deciduous Forest ◽  
Sandy Soils ◽  
The United States ◽  
Eastern Deciduous Forest ◽  
Rock Outcrops ◽  
Native North American ◽  
Forest Region ◽  
Riparian Habitats

Solidago nemoralis, the gray goldenrod, is a polycarpic hemicryptophyte that reproduces vegetatively from branched caudices. This native North American species is morphologically variable throughout its range, and includes an eastern (ssp. nemoralis) and western (ssp. decemflora) race. The eastern subspecies occurs throughout the eastern deciduous forest region of North America and is commonly diploid, though tetraploids do occur throughout. The western race typically occurs on the prairies and is strictly tetraploid. The species occupies riparian habitats, rock outcrops and open fields and roadsides and grows best in well-drained sandy soils in full sunlight. Although the species is weedy in both Canada and the United States it is not noxious. Key words: Solidago nemoralis, gray goldenrod, verge d'or des bois, Asteraceae, Compositae

scholarly journals Cretaceous vegetational change: a biomal perspective

1992 ◽  
Vol 6 ◽  
pp. 295-295
Author(s):  
Garland R. Upchurch
Keyword(s):  
Species Diversity ◽  
North America ◽  
Late Cretaceous ◽  
High Latitude ◽  
Deciduous Forest ◽  
Terrestrial Ecosystems ◽  
High Latitudes ◽  
Coastal Regions ◽  
Show Evidence ◽  
Angiosperm Pollen

The Cretaceous rise of flowering plants marked an important transition in the modernization of terrestrial ecosystems. Well documented is the diversification of angiosperm pollen during the mid-Cretaceous and the migration of angiosperms from low latitudes to middle and high latitudes during the Barremian to Cenomanian. Global compilations of “species” diversity indicate a rapid rise in angiosperm diversity during the Albian to Cenomanian. This rise parallels a decline in the species diversity of archaic pteridophytes and the gymnosperm orders Cycadales, Bennettitales, Ginkgoales, Czekanowskiales, and Caytoniales. Late Cretaceous floras show more gradual trends in species diversity than mid-Cretaceous floras.Megafloral reconstructions of vegetation and climate for North America and other continents indicate warm temperatures in coastal regions of middle to high latitudes. Cretaceous biomes, however, often cannot be compared closely with Recent biomes. During much of the Cretaceous, conifers and other gymnosperms shared dominance with angiosperms in tropical and subtropical vegetation, unlike the Recent. During the Late Cretaceous, tropical rainforest was areally restricted. The few known leaf megafloras from equatorial regions indicate subhumid, rather than rainforest, conditions. Desert and semi-desert were widespread at lower latitudes and are documented by the occurrence of evaporite minerals in China, Africa, Spain, Mexico, and South America. Mid-latitude vegetation consisted of open-canopy broadleaved and coniferous evergreen woodlands that existed under subhumid conditions and low seasonality. High-latitude vegetation of the Northern Hemisphere consisted of coniferous and broadleaved deciduous forest, rather than boreal forest and tundra. High-latitude vegetation from coastal regions of the Southern Hemisphere consisted of evergreen conifers and angiosperms. Rainforest conditions appear to have been largely restricted to polar latitudes.Data on relative abundance, though often incomplete, indicate that angiosperms became ecologically important in tropical to warm subtropical broadleaved evergreen forests and woodlands by the Cenomanian. However, their rise to dominance took longer in other biomes. Conifers formed an important component of many Late Cretaceous biomes, and the persistence of archaic gymnosperms was strongly influenced by climate. Deciduous Ginkgoales, Czekanowskiales, Bennettitales, and Caytoniales are rare to absent in Late Cretaceous megafloras from warm subtropical to tropical climates, but they persist in megafloras from cooler climates. Archaic conifers such as Frenelopsis occur in megafloras representing low-latitude desert and semi-desert, but they are generally absent in more humid assemblages. Within mid-latitude broadleaved and coniferous evergreen woodland from North America, conifers show evidence for co-dominance with angiosperms into the early Maastrichtian. However, this co-dominance appears to have ended by latest Maastrichtian, which implies that vegetational reorganization occurred during the last few million years of the Cretaceous in North America.

Changing Patterns in the Holocene Pollen Record of Northeastern North America: A Mapped Summary

1977 ◽  
Vol 8 (1) ◽  
pp. 64-96 ◽  
Author(s):  
J. Christopher Bernabo ◽  
Thompson Webb
Keyword(s):  
North America ◽  
Large Scale ◽  
Deciduous Forest ◽  
Rapid Expansion ◽  
Early Holocene ◽  
Pollen Record ◽  
Data Set ◽  
Northeastern North America ◽  
The Holocene ◽  
Changing Patterns

By mapping the data from 62 radiocarbon-dated pollen diagrams, this paper illustrates the Holocene history of four major vegetational regions in northeastern North America. Isopoll maps, difference maps, and isochrone maps are used in order to examine the changing patterns within the data set and to study broad-scale and long-term vegetational dynamics. Isopoll maps show the distributions of spruce (Picea), pine (Pinus), oak (Quercus), herb (nonarboreal pollen groups excluding Cyperaceae), and birch + maple + beech + hemlock (Betula, Acer, Fagus, Tsuga) pollen at specified times from 11,000 BP to present. Difference maps were constructed by subtracting successive isopoll maps and illustrate the changing patterns of pollen abundances from one time to the next. The isochrone maps portray the movement of ecotones and range limits by showing their positions at a sequence of times during the Holocene. After 11,000 BP, the broad region over which spruce pollen had dominated progressively shrank as the boreal forest zone was compressed between the retreating ice margin and the rapidly westward and northward expanding region where pine was the predominant pollen type. Simultaneously, the oak-pollen-dominated deciduous forest moved up from the south and the prairie expanded eastward. By 7000 BP, the prairie had attained its maximum eastward extent with the period of its most rapid expansion evident between 10,000 and 9000 BP. Many of the trends of the early Holocene were reversed after 7000 BP with the prairie retreating westward and the boreal and other zones edging southward. In the last 500 years, man's impact on the vegetation is clearly visible, especially in the greatly expanded region dominated by herb pollen. The large scale changes before 7000 BP probably reflect shifts in the macroclimatic patterns that were themselves being modified by the retreat and disintegration of the Laurentide ice sheet. Subsequent changes in the pollen and vegetation were less dramatic than those of the early Holocene.

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