Holocene history of forest trees in southern Ontario

1987 ◽  
Vol 65 (9) ◽  
pp. 1792-1801 ◽  
Author(s):  
K. D. Bennett
Keyword(s):  
Acer Saccharum ◽  
Pinus Banksiana ◽  
Late Holocene ◽  
Accumulation Rate ◽  
Pinus Strobus ◽  
Fagus Grandifolia ◽  
Forest Trees ◽  
Southern Ontario ◽  
History Of ◽  
Available Information

Three new Holocene pollen percentage and accumulation rate diagrams for southern Ontario are presented. They greatly increase the available information on the history of the area's forest trees and permit a discussion of the competitive interactions that have brought about the forest pattern seen today. In the earliest Holocene, the forests were dominated by Picea, which was replaced by first Pinus banksiana–resinosa and then Pinus strobus. In extreme southern Ontario, Pinus strobus was replaced by Acer saccharum and Fagus grandifolia, but in the area east of Georgian Bay, Tsuga canadensis became the dominant, and near Mattawa, Betula (probably lutea). Late Holocene stability of forests is considered to be a function of the lack of taxa better able to compete than those already present.

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.

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.

Relationship between canopy disturbance history and current sapling density of Fagus grandifolia and Acer saccharum in a northern hardwood landscape

2008 ◽  
Vol 38 (2) ◽  
pp. 216-225 ◽  
Author(s):  
Philippe Nolet ◽  
Daniel Bouffard ◽  
Frédérik Doyon ◽  
Sylvain Delagrange
Keyword(s):  
Acer Saccharum ◽  
Negative Relationship ◽  
Basal Area ◽  
Fagus Grandifolia ◽  
Partial Cutting ◽  
Soil C ◽  
Clear Cutting ◽  
Canopy Disturbance ◽  
History Of ◽  
Overstory Trees

To shed light on the currently increasing proportion of Fagus grandifolia Ehrh. saplings in the tolerant hardwood forests of Quebec, we studied 48 Acer saccharum Marsh. dominated stands with contrasting histories of canopy disturbance: old commercial clear-cutting (CC), old fire (F), and either one or two partial cuts (1PC and 2PC). Our results indicated that higher densities of both F. grandifolia and A. saccharum saplings were associated with partial cutting histories (1PC and 2PC) than with severe canopy disturbance (CC and F). The density of F. grandifolia saplings was not related to any soil or stand characteristics in stands with a history of severe canopy disturbance. However, in stands with a history of partial canopy disturbances, the relative density of F. grandifolia saplings as compared with A. saccharum was related to soil C/N ratio and the presence of F. grandifolia overstory trees, whereas the absolute density showed a negative relationship with stand basal area. Therefore, it appears that partial canopy disturbances favored the regeneration of F. grandifolia relative to A. saccharum, whereas severe canopy disturbances may have provided an advantage to A. saccharum. We suggest that the presence of a light threshold can explain this shift in sapling performance between these two species.

The 8200-year vegetation history of an urban woodland as reconstructed from pollen and plant remains

Botany ◽  
2017 ◽  
Vol 95 (2) ◽  
pp. 163-172 ◽  
Author(s):  
Martin Lavoie ◽  
Pierre J.H. Richard
Keyword(s):  
Spatial Scale ◽  
Acer Saccharum ◽  
Vegetation History ◽  
Acer Rubrum ◽  
Fagus Grandifolia ◽  
Small Scale ◽  
Plant Remains ◽  
Local Plant ◽  
History Of ◽  
Urban Woodland

Data on the long term evolution of urban forests are rare. Using pollen and macrofossil analyses of a sediment core collected in a swampy forest hollow on Île aux Chats, an island in Bois-de-Saraguay woodland park in Montreal (Quebec), the postglacial history of a maple forest was reconstructed at a local spatial scale for the last 8200 years. Results show that after Île aux Chats emerged from the waters of Lake Lampsilis, it was rapidly colonized by a maple forest that was already diversified 8000 years ago. More than half of the vascular species identified in the macrofossil assemblages are absent from the local plant community today, notably coniferous species (Pinus resinosa, Larix laricina, Picea mariana). Other plants have multiplied their populations over time (Tilia americana, Tsuga canadensis, Acer rubrum). The maple forest was probably sustained by a small-scale gap dynamic caused by windthrow, fires having apparently been very rare. Fagus grandifolia, never abundant locally in the past, is observed to be currently expanding, and could eventually compete with Acer saccharum. This study constitutes not only a rare plurimillenial study of an urban woodland in eastern North America, but also of a maple forest at a local spatial scale.

NEW RECORDS AND NOTES OF SALTATORIA (ORTHOPTERA) IN ONTARIO

1942 ◽  
Vol 74 (6) ◽  
pp. 97-98 ◽  
Author(s):  
F. A. Urquhart
Keyword(s):  
North Carolina ◽  
Pinus Banksiana ◽  
New Records ◽  
Pinus Strobus ◽  
Pinus Resinosa ◽  
Jack Pine ◽  
Red Pine ◽  
White Pine ◽  
Southern Ontario

Oecanthus pini Beutenmuller. Since O. pini is known to range from Massachusetts west to Ohio and south to North Carolina, it is not surprising to find it in extreme southern Ontario. The specimens here recorded were found on white pine (Pinus strobus L.), red pine (Pinus resinosa Sol. and jack pine (Pinus Banksiana Lam.) in an area devoted to reforestation.

Holocene history of forest trees on the Bruce Peninsula, southern Ontario

1992 ◽  
Vol 70 (1) ◽  
pp. 6-18 ◽  
Author(s):  
K. D. Bennett
Keyword(s):  
Principal Components Analysis ◽  
Principal Components ◽  
Deciduous Forest ◽  
Fagus Grandifolia ◽  
Forest History ◽  
Forest Composition ◽  
Southern Ontario ◽  
Historical Factors ◽  
History Of ◽  
Components Analysis

Two new pollen sequences from the Bruce Peninsula, southern Ontario, demonstrate the Holocene history of forests in the area. During the mid- and late Holocene, the southern portion of the peninsula supported a rich deciduous forest, dominated by Acer saccharum and Fagus grandifolia, while the northern portion was dominated by a forest with a much higher proportion of conifers. These two sites are compared numerically with a third site, on Manitoulin Island, by means of principal components analysis. Despite similar bedrock, soils, climate, and topography, the three pollen sequences show a remarkable divergence of Holocene forest history. The role of historical factors in determining forest composition may be much greater than previously appreciated. This study emphasises the need to understand the magnitude of variation between pollen sequences within uniform terrain before ascribing the differences in pollen sequences from contrasting environments (because of climate, soils or topography) to the factors causing the obvious contrast. Key words: Holocene forest history, pollen analysis, principal components analysis, Bruce Peninsula, southern Ontario.

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