Raised bogs in eastern North America: transitions in landforms and gross stratigraphy

1986 ◽  
Vol 64 (2) ◽  
pp. 395-415 ◽  
Author(s):  
Paul H. Glaser ◽  
Jan A. Janssens
Keyword(s):  
North America ◽  
Early Stage ◽  
Regional Scale ◽  
Forest Growth ◽  
Eastern North America ◽  
Regional Survey ◽  
Raised Bogs ◽  
Geographic Patterns ◽  
Peat Profile ◽  
Peat Stratigraphy

A regional survey of 60 raised bogs was made in eastern North America to determine the geographic patterns of bog landforms and gross peat stratigraphy. Three major types of bogs were identified: (i) midcontinental forested bogs with a longitudinal crest, radiating lines of forest growth, and an actively growing surface of loose Sphagnum hummocks, (ii) non-forested northern or maritime bogs with a convex or plateau shape, various networks of pools, hollows, and firm compact hummocks, and a more slowly growing surface that produces deeply humified bands or recurrence surfaces throughout the peat profile, and (iii) semiforested continental bogs with a forested crest, networks of linear hummocks and flat hollows on the lower flanks, and shallow expanding pools on the hollows. The peat stratigraphy on these semiforested bogs is also intermediate, with recurrence bands in the compact upper portions of the profile, becoming looser and more irregular toward the bottom. The geographic changes in landform patterns and gross peat stratigraphy indicate that forested bogs with a linear crest represent an early stage of bog development and are replaced in time by a nonforested plain with pools as changes in the slope and the hydrologic properties of the surficial layers of peat restrict runoff and infiltration, producing a rise in the water table. Thus on a regional scale autogenic bog processes may be as important as climate in controlling bog patterns and peat stratigraphy.

scholarly journals Are marginal balsam fir and eastern white cedar stands relics from once more extensive populations in north-eastern North America?

The Holocene ◽  
2018 ◽  
Vol 28 (10) ◽  
pp. 1672-1679 ◽  
Author(s):  
Abed Nego Jules ◽  
Hugo Asselin ◽  
Yves Bergeron ◽  
Adam A Ali
Keyword(s):  
North America ◽  
Regional Scale ◽  
Continuous Distribution ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Eastern North America ◽  
White Cedar ◽  
North Eastern ◽  
The Matrix ◽  
Eastern White Cedar

Marginal stands of balsam fir ( Abies balsamea [L.] Mill.) and eastern white cedar ( Thuja occidentalis L.) are found north of their limits of continuous distribution in eastern North America. Regional-scale paleoecological studies have suggested that fir and cedar populations could have had larger extents in the past. This study aimed at verifying this hypothesis at the local scale. Wood charcoal fragments were collected from the soils of two marginal fir and cedar stands as well as from 15 sites in the surrounding forest matrix where the species are absent currently. Anatomical identification and radiocarbon-dating showed that fir was more extensive in the study area until about 680 cal. BP, representing up to 31% of the charcoal assemblages at sites where it is currently absent. The evidence is less conclusive for cedar, however, although some of the charcoal fragments from the matrix sites could have been either fir or cedar (undistinguishable). Most of the dated fir/cedar charcoal in the matrix were from the ‘Medieval Warm Period’ (ca. 1000 cal. BP), suggesting contraction may have occurred at that time. Marginal fir – and possibly cedar – stands are thus relics of once more extensive populations. Fire is likely the main factor having contributed to the contraction of the species’ distributions. Fir and cedar are now relegated to areas where fires are less frequent and severe, such as the shores of lakes and rivers.

scholarly journals Accumulated Heating and Chilling Are Important Drivers of Forest Phenology and Productivity in the Algonquin-to-Adirondacks Conservation Corridor of Eastern North America

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 282
Author(s):  
Michael A. Stefanuk ◽  
Ryan K. Danby
Keyword(s):  
Climate Change ◽  
North America ◽  
Annual Variation ◽  
Forest Growth ◽  
Eastern North America ◽  
Seasonal Temperature ◽  
Climate Data ◽  
Random Forest Regression ◽  
Recent Climate ◽  
Climatic Drivers

Research Highlights: Forest phenology and productivity were responsive to seasonal heating and chilling accumulation, but responses differed across the temperature range. Background and Objectives: Temperate forests have responded to recent climate change worldwide, but the pattern and magnitude of response have varied, necessitating additional studies at higher spatial and temporal resolutions. We investigated climatic drivers of inter-annual variation in forest phenology and productivity across the Algonquin-to-Adirondacks (A2A) conservation corridor of eastern North America. Methods: We used remotely sensed indices from the AVHRR sensor series and a suite of gridded climate data from the Daymet database spanning from 1989–2014. We used random forest regression to characterize forest–climate relationships between forest growth indices and climatological variables. Results: A large portion of the annual variation in phenology and productivity was explained by climate (pR2 > 80%), with variation largely driven by accumulated heating and chilling degree days. Only very minor relationships with precipitation-related variables were evident. Conclusions: Our results indicate that anthropogenic climate change in the A2A has not yet reached the point of triggering widespread changes in forest phenology and productivity, but the sensitivity of forest growth to inter-annual variation in seasonal temperature accumulation suggests that more temperate forest area will be affected by climate change as warming continues.

The Identification and Study of Indian Shell Middens in Eastern North America: 1643–1861

1986 ◽  
Vol 6 (3) ◽  
pp. 227-243 ◽  
Author(s):  
Andrew L. Christenson
Keyword(s):  
Nineteenth Century ◽  
Civil War ◽  
North America ◽  
East Coast ◽  
Eastern North America ◽  
Shell Midden ◽  
Shell Middens ◽  
Work Done

Although the interest in shell middens in North America is often traced to reports of the discoveries in Danish kjoekkenmoeddings in the mid-nineteenth century, extensive shell midden studies were already occurring on the East Coast by that time. This article reviews selected examples of this early work done by geologists and naturalists, which served as a foundation for shell midden studies by archaeologists after the Civil War.

HAVE WE SEEN THE LARGEST EARTHQUAKES IN EASTERN NORTH AMERICA?

2018 ◽  
Author(s):  
James S. Neely ◽  
◽  
Seth Stein ◽  
Miguel Merino ◽  
John Adams
Keyword(s):  
North America ◽  
Eastern North America
Sign in / Sign up

Export Citation Format

Share Document