Behavior of urease added to unsterilized, steam-sterilized, and gamma radiation-sterilized black spruce humus

1970 ◽  
Vol 16 (9) ◽  
pp. 865-870 ◽  
Author(s):  
M. R. Roberge
Keyword(s):  
Gamma Radiation ◽  
Picea Mariana ◽  
Black Spruce ◽  
Organic Horizon ◽  
Urea Fertilizer ◽  
Upper Limit ◽  
All Solutions ◽  
Mill Stand

Because of the widespread use of urea fertilizer, it became evident that an assessment of urease addition on natural ureolysis was pertinent. Samples of each layer of the surface organic horizon of a black spruce (Picea mariana Mill.) stand at Baie-Comeau, Quebec, were treated with urease then tested for ureolysis activity. Added urease was active in all samples; the increase of activity was affected by the type of sterilization treatment used and the layer of the surface organic horizon. Additional ureolysis was greatest in unsterilized samples, less in radiation-sterilized samples, least in steam-sterilized samples, and decreased with depth of layers. Autoclaving inhibited activity of urease added previously or subsequently while irradiation had a lesser effect. Every layer had an upper limit of urease adsorption and was characterized by a definite capacity to adsorb urease which increased with depth of layers. The pattern of ureolysis observed when urease was added to solutions obtained from layer samples was similar to that observed when urease was added to the layer samples themselves. All solutions inhibited the action of added urease.

Respiration rates for determining the effects of urea on the soil-surface organic horizon of a black spruce stand

1976 ◽  
Vol 22 (9) ◽  
pp. 1328-1335 ◽  
Author(s):  
M. R. Roberge
Keyword(s):  
Incubation Period ◽  
Picea Mariana ◽  
Black Spruce ◽  
Soil Surface ◽  
Water Holding Capacity ◽  
Organic Horizon ◽  
Endogenous Respiration ◽  
Respiration Rates ◽  
Water Holding ◽  
Field Plots

The respiration rates of microflora of layers of soil-surface organic horizon of a black spruce (Picea mariana (Mill.) B.S.P.) stand have been studied manometrically under controlled conditions of moisture, temperature, and aeration in the presence of urea and other nitrogen and mineral amendments. L, F1, and F2 samples from field plots fertilized with 448 kg N/ha as urea in 1961 had still in 1971 greater respiration rates than similar samples from unfertilized field plots. In lab tests, addition of urea (112, 280, and 448 kg N/ha or 875, 2187, and 3500 ppm N) stimulated the endogenous respiration of each layer. The stimulation was greater when 2187 ppm N was applied and when moisture and temperature of the layers were maintained at 60% water-holding capacity and 20 °C during the 42-day incubation period. Addition of Mg, Ca, and K to urea-fertilized layers increased respiration while P and S decreased it. Addition of NH4NO3 and (NH4)SO4 impaired the endogenous respiration. The endogenous respiration and moisture, temperature, and fertilizer effects decreased in the order L, F1, and F2 layers.

Holocene Relict Woodlands at the Eastern Canadian Treeline

1993 ◽  
Vol 39 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Serge Payette ◽  
Claude Morneau
Keyword(s):  
Picea Mariana ◽  
Direct Evidence ◽  
Black Spruce ◽  
Strong Support ◽  
Organic Horizon ◽  
Hudson Bay ◽  
Humid Climate ◽  
Open Forest

AbstractWe present direct evidence for the relict nature of lichenspruce woodlands thriving at treeline, using 14C-dated stands growing in the humid climate of eastern Hudson Bay in northern Québec. Black spruce, Picea mariana (Mill.) BSP, forms two groups of relict stands: a Neoglacial group of postfire origin dating between 2000 and 900 yr B.P. and a pre-Neoglacial group most likely established between 4500 and 3200 yr B.P. The latter group shows no evidence of fire (absence of charcoal under topsoil organic horizon). The stands are exceptional because they probably are the direct lineages of the primeval forests that colonized the land sometime after deglaciation. The structure of the relict lichen-spruce communities gives strong support to the current thesis that considers lichen-spruce woodland as a self-perpetuating open forest, typical of the subarctic environment.

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
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