Analyse macrofossile d'une palse subarctique (Québec nordique)

1995 ◽  
Vol 73 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Claude Lavoie ◽  
Serge Payette
Keyword(s):  
Picea Mariana ◽  
Structural Changes ◽  
Black Spruce ◽  
Vascular Plant ◽  
Time Of Arrival ◽  
Peat Deposits ◽  
Betula Glandulosa ◽  
Dwarf Birch ◽  
Forest Limit ◽  
Hippuris Vulgaris

Plant and animal macrofossils (vascular plant, moss, fungus, bryozoan, cladoceran and coleoptera remains) were analyzed to reconstitute the development of a palsa peat located at the northwestern forest limit of subarctic Quebec (57°45′N., 76°15′W.) and to detect any black spruce (Picea mariana) remains older than the presumed time of arrival of the species in the study area (4560 BP), after the deglaciation. The oldest peat deposits were formed in a fen with many shallow pools between 5850 and 4500 BP. The flora was mainly composed of aquatic taxa (Ranunculus trichophyllus, Potamogeton spp., Hippuris vulgaris). Around 4500 BP, there was a shift from a very wet fen to a sedge fen with Potentilla palustris and Menyanthes trifoliata. From 3700 to 1950 BP, most plant remains were wood fragments of dwarf birch (Betula glandulosa). The formation of the palsa occurred after 1950 BP. The development of this peatland is similar to that of other palsa peatlands of subarctic Quebec, except that it is characterized by the presence of a thick peat layer composed of Betula glandulosa fragments at the top of the palsa. There were no black spruce remains older than 4560 BP. Three peaks of coleoptera abundance were identified at 4400, 3800, and 2700 BP, respectively. Most of the coleoptera taxa being hygrophilous, it was not possible to infer structural changes in the peatland from their fragments. Key words: palsa peatland, macrofossil analysis, subarctic Quebec, Betula glandulosa, Picea mariana, beetles.

Régression holocène du couvert coniférien à la limite des forêts (Québec nordique)

1985 ◽  
Vol 63 (7) ◽  
pp. 1213-1225 ◽  
Author(s):  
Réjean Gagnon ◽  
Serge Payette
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Climatic Conditions ◽  
Larix Laricina ◽  
Charcoal Analysis ◽  
Mosaic Landscape ◽  
The Past ◽  
Modern Period ◽  
History Of ◽  
Forest Limit

The occurrence of tamarack (Larix laricina (Du Roi) K. Koch) and black spruce (Picea mariana (Mill.) B.S.P.) macrofossils or subfossils on the tundroid patches at the forest limit indicates that those patches were colonized by trees in the past. The aim of this study is to reconstruct the fluctuations of the coniferous formations by macrofossil analysis. More than 465 macrofossils and 30 charcoals were collected, 31 and 23 of which, respectively, were 14C dated. The results of charcoal analysis indicated that fires were more frequent in the southern part of the forest limits than in the northern part. During the last millenium three periods of fire (modern, 400, and 900 years) were noted in the southern part, two periods (modern and 600 years) at the forest limit, and none north of the forest limit. The majority of collected macrofossils are from the modern period; their death is related to the action of fire. The mosaic landscape of the forest tundra is related to a deterioration of the climatic conditions coupled with the history of fires.

Clonal and nonclonal genetic structure of subarctic black spruce (Picea mariana) populations in Yukon territory

Botany ◽  
2011 ◽  
Vol 89 (2) ◽  
pp. 133-140 ◽  
Author(s):  
Marios Viktora ◽  
Rodney A. Savidge ◽  
Om P. Rajora
Keyword(s):  
Genetic Structure ◽  
Picea Mariana ◽  
Black Spruce ◽  
A Priori ◽  
Nuclear Genome ◽  
Yukon Territory ◽  
Fire Disturbance ◽  
Clone Size ◽  
Flat Terrain ◽  
Individual Trees

Black spruce (Picea mariana) reproduces sexually from seeds and asexually by layering. There is a prevalent concept that clonal reproduction maintains populations of this species in the subarctic and arctic regions. We used microsatellite DNA markers of the nuclear genome to investigate the genetic structure of montane and subalpine black spruce populations from the Western Yukon Plateau in relation to this concept. Sixty individual trees at a minimum distance of 4 m from each other were sampled from each of four populations and individual trees were genotyped for eight microsatellite loci. Each of the 60 individuals from three montane pure black spruce populations growing on flat terrain at relatively low elevations had unique multilocus genotypes, indicating an absence of clonal structure in those populations. However, in an anthropologically undisturbed climax white spruce-dominated subalpine black spruce population on a northwest slope near Mount Nansen, the majority of the sampled individuals belonged to eight genetically distinct clones (genets). Clone size differed by altitude, the dominant genet being nearest the timberline–tundra ecotone. The results indicate that black spruce reproduction is variable and adaptive, being primarily sexual in flat-terrain montane populations previously subjected to fire disturbance, but mixed vegetative–sexual in the anthropogenically undisturbed subalpine population. This study is the first to employ molecular markers a priori to examine the mode of reproduction in natural black spruce populations.

scholarly journals Comparative Height Growth of Eastern Larch and Black Spruce in Northwestern Ontario

1978 ◽  
Vol 54 (6) ◽  
pp. 296-297 ◽  
Author(s):  
Douglas A. Mead
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Height Growth ◽  
Larix Laricina ◽  
Stem Analysis ◽  
Northwestern Ontario ◽  
Analysis Methods ◽  
Spruce Stands

Height growth of eastern larch (Larix laricina (Du Roi) K. Koch) and black spruce (Picea mariana (Mill.) B.S.P.) was determined using standard stem analysis methods on trees from two sites in northwestern Ontario. The data were obtained from mixed larch-spruce stands which were relatively undisturbed. The larch exhibited substantially better height growth than the spruce through age 65.

SEASONAL DAMAGE BY INSECTS AND SQUIRRELS TO FEMALE REPRODUCTIVE STRUCTURES OF BLACK SPRUCE, PICEA MARIANA (MILL.) B.S.P.

1988 ◽  
Vol 120 (12) ◽  
pp. 1113-1121 ◽  
Author(s):  
Y.H. Prévost ◽  
J.E. Laing ◽  
V.F. Haavisto
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrel ◽  
Red Squirrels ◽  
Reproductive Structures ◽  
Cone Axis ◽  
Viable Seeds ◽  
Cone Growth

AbstractThe seasonal damage to female reproductive structures (buds, flowers, and cones) of black spruce, Picea mariana (Mill.) B.S.P., was assessed during 1983 and 1984. Nineteen insects (five Orders) and the red squirrel, Tamiasciurus hudsonicus (Erxleben), were found feeding on these reproductive structures. Collectively, these organisms damaged 88.9 and 53.5% of the cones in 1983 and 1984, respectively. In the 2 years, Lepidoptera damaged 61.8% of the cones in 1983 and 44.4% of the cones in 1984. The spruce budworm, Choristoneura fumiferana (Clem.), and the spruce coneworm, Dioryctria reniculelloides Mut. and Mun., were the most important pests. Cones damaged by Lepidoptera could be classed into three categories: (a) severe, yielding no seeds; (b) moderate, yielding 22.3 seeds per cone; and (c) light, yielding 37.5 seeds per cone. Undamaged cones yielded on average 39.9 seeds per cone. Red squirrels removed 18.8% of the cones in 1983 and none in 1984. The spruce cone axis midge, Dasineura rachiphaga Tripp, and the spruce cone maggot, Lasiomma anthracinum (Czerny), caused minor damage in both years. Feeding by spruce cone axis midge did not reduce cone growth significantly or the number of viable seeds per cone, but feeding by the spruce cone maggot did. During both years new damage by insects to the female reproductive structures of the experimental trees was not observed after mid-July. In 1983 damage by red squirrels occurred from early to late September. In 1984 damage to cones on trees treated with dimethoate was 15.6% compared with 53.5% for untreated trees, without an increase in the number of aborted cones.

Prediction and evaluation of borate distribution in Eastern black spruce (Picea mariana var. mariana) wood products

2015 ◽  
Vol 49 (3) ◽  
pp. 457-473 ◽  
Author(s):  
Thierry Koumbi-Mounanga ◽  
Paul I. Morris ◽  
Myung J. Lee ◽  
Nasmus M. Saadat ◽  
Brigitte Leblon ◽  
...  
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Wood Products

scholarly journals The Cuito catchment of the Okavango system: a vascular plant checklist for the Angolan headwaters

PhytoKeys ◽  
2018 ◽  
Vol 113 ◽  
pp. 1-31 ◽  
Author(s):  
David J. Goyder ◽  
Nigel Barker ◽  
Stoffel P. Bester ◽  
Arnold Frisby ◽  
Matt Janks ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Conservation Planning ◽  
Vascular Plant ◽  
River System ◽  
Vegetation Types ◽  
Additional Species ◽  
System A ◽  
Peat Deposits ◽  
First Time

This paper aims to provide a baseline for conservation planning by documenting patterns of plant diversity and vegetation in the upper catchment of the Cuito River. 417 species are recorded from this region. Nine of these are species potentially new to science. Ten species are newly recorded from Angola, with an additional species only recorded previously within Angola from the northern enclave of Cabinda. The 108 new provincial records for Moxico clearly indicate the lack of collections from Angola’s largest province. We note the existence of extensive peat deposits in the Cuito river system for the first time and suggest that one of Barbosa’s vegetation types in the area needs to be reassessed.

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