scholarly journals Tracking Open Versus Closed‐Canopy Boreal Forest Using the Geochemistry of Lake Sediment Deposits

2019 ◽  
Vol 124 (5) ◽  
pp. 1278-1289
Author(s):  
C. Bastianelli ◽  
A. A. Ali ◽  
Y. Bergeron ◽  
C. Hély ◽  
D. Paré
Keyword(s):  
Boreal Forest ◽  
Lake Sediment ◽  
Sediment Deposits ◽  
Closed Canopy ◽  
Open Versus

Organic, elemental, and geochemical contributions to lake sediment deposits during severe spruce beetle (Dendroctonus rufipennis) disturbances

2013 ◽  
Vol 289 ◽  
pp. 78-89 ◽  
Author(s):  
Jesse L. Morris ◽  
Peter C. le Roux ◽  
Anthony N. Macharia ◽  
Andrea Brunelle ◽  
Elizabeth G. Hebertson ◽  
...  
Keyword(s):  
Lake Sediment ◽  
Dendroctonus Rufipennis ◽  
Sediment Deposits ◽  
Spruce Beetle

CONTRIBUTIONS TO THE HOLOCENE PALEOECOLOGY OF WESTCENTRAL CANADA: I. THE RIDING MOUNTAIN AREA

1964 ◽  
Vol 42 (2) ◽  
pp. 181-196 ◽  
Author(s):  
J. C. Ritchie
Keyword(s):  
Boreal Forest ◽  
Lake Sediment ◽  
Pollen Analysis ◽  
Deciduous Forests ◽  
Pollen Spectrum ◽  
Spruce Forest ◽  
Mountain Area ◽  
The Holocene ◽  
Carbon 14 ◽  
Spruce Wood

The results of pollen analysis of three sections of lake sediment, sampled in the Riding Mountain area of Manitoba, suggest a tentative division of each into four zones. The lower, interpreted as representing a closed white spruce forest, is followed by an apparently treeless episode tentatively interpreted as a grassland phase; this is followed by a zone which suggests indirectly the prevalence of deciduous forests, possibly dominated by poplar, birch, and oak. The development of the mixed boreal forest, which prevails today, is marked by a rise in the spruce and alder curves. The suggestion that the sections are post-Valders in age is corroborated to some extent by a carbon-14 age measurement of 9570 years from a sample of spruce wood excavated from the bottom of a filled-in kettle in the vicinity; associated gyttja yielded a pollen spectrum very similar to the I zones of the diagrams.

Absolute pollen frequencies and carbon-14 age of a section of Holocene Lake sediment from the Riding Mountain area of Manitoba

1969 ◽  
Vol 47 (9) ◽  
pp. 1345-1349 ◽  
Author(s):  
J. C. Ritchie
Keyword(s):  
Boreal Forest ◽  
Lake Sediment ◽  
Present Form ◽  
Accumulation Rates ◽  
Mountain Area ◽  
Carbon 14 ◽  
Pollen Accumulation Rates ◽  
Grassland Type ◽  
Aspen Parkland ◽  
Frequency Diagram

A section of Holocene lake sediment in the Southern Boreal Forest of Manitoba was re-sampled, and the sedimentation rate (0.039 cm per annum) calculated from eight carbon-14 age determinations. Pollen accumulation rates were computed, and an absolute pollen frequency diagram constructed. It suggests modifications of an earlier reconstruction of vegetation, based on relative pollen frequencies. A spruce-dominated assemblage occurred from about 11 500 to 10 000 B.P., when there was a change to a treeless vegetation of a grassland type. This persisted until about 2500 B.P., with the possible interpolation of an aspen parkland phase from 6500 to 2500 B.P. The boreal forest in its present form (dominated by spruce, birch, and aspen, with local occurrences of pine, fir, larch, and oak) returned at 2500 B.P., presumably in response to a deterioration in climate (cooler and (or) wetter).

Size and spatial structure of the soil and lacustrine charcoal pool across a boreal forest watershed

2013 ◽  
Vol 80 (3) ◽  
pp. 417-424 ◽  
Author(s):  
Mikael Ohlson ◽  
Isabella Kasin ◽  
Anveig Nordtug Wist ◽  
Anne E. Bjune
Keyword(s):  
Boreal Forest ◽  
Lake Sediment ◽  
Forest Soils ◽  
Forest Fires ◽  
Spatial Scales ◽  
Rapid Degradation ◽  
Soil Charcoal ◽  
Forest Watershed ◽  
Geostatistical Approach ◽  
Extreme Variation

Forest fires convert a proportion of the burning vegetation into charcoal that is stored in forest soils and lake sediments. In this paper we use a geostatistical approach to present a detailed analysis of the size of the charcoal pool and its spatial variation in a boreal forest watershed including its lake sediment. The amount of soil charcoal averaged 179 g/m2 and ranged from 0 to 3600 g/m2 in the watershed. There was an extreme variation in the size of the charcoal pool over fine (cm) spatial scales. For example, the amount of charcoal in the soil could range from 34 to 1646 g/m2 within a distance of 10 cm. Individually dated soil charcoal particles had radiocarbon ages that varied from 630 to 2930 cal yr BP. The lake sediment began accumulating at 10,600 cal yr BP and charcoal accumulation has been practically continuous ever since then, with the largest peak occurring at 6900 cal yr BP. The lake sediment contained more charcoal, 360 g/m2, than the average for forest soil. We interpret this as an indication of a relatively rapid degradation of charcoal in boreal forest soils.

scholarly journals Effects of Savanna Restoration on the Foraging Ecology of Insectivorous Songbirds

The Condor ◽  
2005 ◽  
Vol 107 (4) ◽  
pp. 879-888 ◽  
Author(s):  
Sarah C. Hartung ◽  
Jeffrey D. Brawn
Keyword(s):  
Tree Species ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Foraging Ecology ◽  
Robinia Pseudoacacia ◽  
Canopy Closure ◽  
White Oak ◽  
Open Canopy ◽  
Closed Canopy ◽  
Open Versus

Abstract We studied the foraging behavior of insectivorous songbirds during the breeding season at four sites in Illinois, each with restored open-canopy savanna habitat (65% mean canopy closure) and closed-canopy forests (89% mean canopy closure). We sampled and compared apparent tree species preference, foliage layer preference, and proportional use of different prey-attack maneuvers in the two habitats. In closed-canopy forests, three of nine songbird species foraged in black oak (Quercus velutina) and white oak (Q. alba) more than expected based on availability, and foraged less than expected in shade-tolerant trees such as sugar maple (Acer saccharum) and red elm (Ulmus rubra). Four species also displayed apparent preferences for black locust (Robinia pseudoacacia) and hackberry (Celtis occidentalis). In contrast, songbirds used tree species according to availability in open-canopy habitat. We observed apparent preferences for the shrub and subcanopy vegetation layers (0–5 m and 6–10 m) in open-canopy habitat and apparent preferences for the subcanopy and lower canopy vegetation layers (6–10 m and 11–15 m) in closed-canopy forests. Relative use of prey-attack maneuvers in open versus closed-canopy habitat was significantly different for the Eastern Wood-Pewee (Contopus virens) and the Great Crested Flycatcher (Myiarchus crinitus), but not for foliage-gleaning species. These results suggest that restoration of oak savannas has important effects on the habitat use and foraging ecology of selected insectivorous birds.

scholarly journals A 6 ka BP Reconstruction for the Island of Newfoundland from a Synthesis of Holocene Lake-Sediment Pollen Records

2007 ◽  
Vol 49 (1) ◽  
pp. 163-182 ◽  
Author(s):  
Joyce Brown MacPherson
Keyword(s):  
Boreal Forest ◽  
Lake Sediment ◽  
Balsam Fir ◽  
Indicator Taxa ◽  
Climatic Reconstruction ◽  
The North ◽  
Moisture Availability ◽  
Forest Limit ◽  
Avalon Peninsula ◽  
Pollen Records

ABSTRACT A 6 ka reconstruction for the island of Newfoundland is presented in the context of a synthesis of Holocene pollen records for twelve sites within or at the margin of the boreal forest, five of which are new. Climatic reconstruction is based primarily on representation of the major boreal taxa: balsam fir, spruce, birch and pine, with charcoal data for some sites. The period of greatest Holocene warmth began at 6 ka. Although temperatures at inland sites were at or close to modern values as early as 8.5-8.0 ka, it was not until 6 ka on the Avalon Peninsula, in the southeast, and 5.5 ka in the north, that coastal sites registered expansion of more thermophilous taxa. Thus oceanic warming lagged terrestrial warming. Temperatures during the period of greatest warmth were no more than 1.0°C higher than modern, based on fluctuations of the upper forest limit and post-Hypsithermal contraction of the range of indicator taxa. Fire importance increased after 6 ka as pine expanded, but moisture availability also increased. The first indications of cooling occurred on the coast at 4.5-4.0 ka, but at different times after 4.0 ka inland; thus oceanic cooling led terrestrial cooling. The latest Holocene has been cool, moist and relatively free from fire.

scholarly journals Comparing soil profiles of adjacent forest stands with contrasting tree densities: lichen woodlands vs. black spruce–feathermoss stands in the continuous boreal forest

2018 ◽  
Vol 98 (3) ◽  
pp. 458-468 ◽  
Author(s):  
Rock Ouimet ◽  
Jean-François Boucher ◽  
Pascal Tremblay ◽  
Daniel Lord
Keyword(s):  
Boreal Forest ◽  
Black Spruce ◽  
Basal Area ◽  
Stem Density ◽  
Forest Zone ◽  
Nutrient Pools ◽  
Humus Layer ◽  
C Stocks ◽  
Closed Canopy ◽  
C And N

We studied mature and adjacent open lichen–spruce woodlands (LWs) and closed-canopy spruce–feathermoss stands (FMs) growing under similar edaphic conditions in the continuous boreal forest zone in Quebec (Canada). A total of six pairs of stands were investigated by profile sampling. Stem density, basal area, and biomass were about four times greater in FMs than in LWs on an area basis. In the humus layer, total stocks of C and N and of exchangeable K, Ca, Mg, Al, and Na were 1.4–2.3 times larger in FM than in LW soils. The first 30 cm and the first metre of mineral soils in LWs and FMs displayed similar available nutrient pools except for total C stocks, which were more than twice as large in FM as in LW soils in these soil layers. For the whole profile, total stocks of C and N and stocks of exchangeable Ca and Mg were 1.3–2.6 times larger in FM than in LW soils. These results highlight the low intrinsic fertility of LW soils, primarily due to the humus layer, but also the importance of the biological control of C, N, and mineral nutrients in these boreal soils.

scholarly journals DMP VIII: Palaeohydrology and palaeoenvironment

2009 ◽  
Vol 40 ◽  
pp. 171-178 ◽  
Author(s):  
Nicholas Drake ◽  
Kevin White ◽  
Mustapha Salem ◽  
Simon Armitage ◽  
Ahmed El-Hawat ◽  
...  
Keyword(s):  
Lake Sediment ◽  
Ground Penetrating Radar ◽  
State Of The Art ◽  
Geophysical Survey ◽  
Preliminary Results ◽  
Sediment Deposits ◽  
Palaeoenvironmental Change ◽  
Lacustrine Carbonate ◽  
Ground Penetrating ◽  
Detailed Picture

AbstractThe January 2009 fieldwork season conducted geomorphological and palaeoenviromental surveys in as yet unexplored parts of the Lake Megafazzan Basin, as well as continuing research in the Wadi al-Hayat and Ubari Sand Sea. Lake Megafazzan sediments were investigated at two sites on the eastern margin of the basin. At the first site, east of Tamessah, 24 m of stratigraphy was investigated and found to consist of a lacustrine carbonate unit at the base progressing into a fluvial unit and then an upper carbonate unit. The sediments were sampled for magnetostratigraphy and cosmogenic nucleide dating in order to determine their age. Similar studies were undertaken in the vicinity of the Arial Agricultural Project, where 31 m of section were logged and sampled. Here the sediments were quite different, being composed of a deltaic sequence consisting of stacked channels and palaeosols, thought to represent the outflow delta of the palaeolake. Many new Holocene lake sediment deposits were discovered and sampled in the Wadi al-Hayat and the Ubari Sand Sea, including a 5 m section through Jarma Playa that appears to record the last arid-humid cycle. Lake Gabr 'Awn and the moat round Old Jarma were cored in order to gather a detailed picture of recent palaeoenvironmental change. Finally, we implemented a pilot geophysical survey to test the ability of state-of-the-art Ground Penetrating Radar (UltraGPR) technology for detecting and mapping buried palaeolake sediments under the dunes of the Ubari Sand Sea. The UltraGPR was found to be very effective, detecting palaeolake sediments as much as 60 m beneath the surface. Preliminary results suggest such sediments underlie much of the region.

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