A Cluster Analysis of the D 2 Matrix of White Spruce Stands in Saskatchewan Based on the Maximum-Minimum Principle

1972 ◽  
Vol 60 (3) ◽  
pp. 873 ◽  
Author(s):  
T. Frey ◽  
H. van Groenewoud
Keyword(s):  
Cluster Analysis ◽  
Minimum Principle ◽  
White Spruce ◽  
Spruce Stands ◽  
Maximum Minimum

Variation in response to declining photoperiod among families and stands of white spruce in southeastern Ontario

1979 ◽  
Vol 9 (4) ◽  
pp. 443-448 ◽  
Author(s):  
D. F. W. Pollard ◽  
C. C. Ying
Keyword(s):  
White Spruce ◽  
Adaptive Strategy ◽  
Height Increment ◽  
Base Population ◽  
Local Climate ◽  
The Family ◽  
Family Level ◽  
Spruce Stands ◽  
Controlled Environments ◽  
Free Growth

Newly germinated seedlings of 66 open-pollinated white spruce Piceaglauca (Moench) Voss families from 11 native stands in southeastern Ontario were investigated for responses to declining photoperiod under controlled environments. Amount of height increment (free growth) during a period of declining photoperiod was studied. Variation in duration of free growth was found mostly associated with the family-within-stand component. The stand effect was negligible and decreased as seedlings aged. Lack of stand differentiation suggests that white spruce stands in. southeastern Ontario may have originated from the same base population. High genetic variation at the family level may reflect an adaptive strategy to cope with the extremely variable local climate.

Retention patch size and conservation of saproxylic beetles in boreal white spruce stands

2015 ◽  
Vol 358 ◽  
pp. 98-107 ◽  
Author(s):  
Seung-Il Lee ◽  
John R. Spence ◽  
David W. Langor ◽  
Jaime Pinzon
Keyword(s):  
Patch Size ◽  
White Spruce ◽  
Saproxylic Beetles ◽  
Spruce Stands

Distribution of white spruce lateral fine roots as affected by the presence of trembling aspen: root mapping using simple sequence repeat DNA profiling

2012 ◽  
Vol 42 (8) ◽  
pp. 1566-1576 ◽  
Author(s):  
Derek Joseph Lawrence ◽  
N. Luckai ◽  
W.L. Meyer ◽  
C. Shahi ◽  
A.J. Fazekas ◽  
...  
Keyword(s):  
Simple Sequence Repeat ◽  
White Spruce ◽  
Trembling Aspen ◽  
Soil Layers ◽  
Repeat Dna ◽  
Spruce Stands ◽  
Dna Profiles ◽  
Simple Sequence ◽  
Simple Sequence Repeat Dna ◽  
Mixedwood Stands

Mixedwood forests of white spruce ( Picea glauca (Moench) Voss) and trembling aspen ( Populus tremuloides Michx.) may possess ecological advantages over monospecific white spruce stands. Belowground competition may be reduced through vertically stratified roots; facilitation of growth may occur in upper soil layers through nutrient-rich trembling aspen litterfall. These effects may incentivize white spruce to preferentially exploit upper soil layers in mixedwood stands, resulting in wider root systems. This research contrasted white spruce fine root (diameter <2 mm) distributions in organic layers of white spruce and mixedwood stands. Research occurred at the Fallingsnow Ecosystem Project site in northwestern Ontario. Eighteen plots represented mixedwood and pure white spruce stands. Trees were mapped; foliage and root samples were collected. Roots were separated by species and scanned to determine length. Simple sequence repeat DNA profiles were determined for all white spruce trees and for 45 white spruce root fragments per plot. Root and tree DNA profiles were matched; corresponding distances were calculated. Most (80%) root fragments were within 3.2 m of tree stems. Root prevalence decreased rapidly with distance. Organic layer pH was significantly less acidic in mixedwood plots, but only in one block. A subtle significant trend towards wider root distributions occurred in mixedwood stands.

Are mixtures of aspen and white spruce more productive than single species stands?

1999 ◽  
Vol 75 (3) ◽  
pp. 505-513 ◽  
Author(s):  
Rongzhou Man ◽  
Victor J. Lieffers
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
White Spruce ◽  
Single Species ◽  
Physical Separation ◽  
Soil Resource ◽  
Mixedwood Forests ◽  
Environmental Extremes ◽  
Spruce Stands ◽  
Boreal Mixedwoods

In boreal mixedwood forests, aspen (Populus tremuloides) and white spruce (Picea glauca) commonly grow in mixture. These species may avoid competition through differential shade tolerance, physical separation of canopies, phenological differences, successional separation, and differences in soil resource utilization. Aspen may also be able to positively affect the growth of white spruce by improving litter decomposition and nutrient cycling rates, controlling grass and shrub competition, ameliorating environmental extremes, and reducing pest attack. These positive relationships likely make mixed-species stands more productive than pure stands of the same species. The evidence regarding the productivity of pure versus mixed aspen/white spruce stands in natural unmanaged forests is examined in this paper. Key words: Tree mixture; productivity; boreal mixedwoods; aspen; white spruce

SCOLYTID FLIGHT IN WHITE SPRUCE STANDS IN ALASKA

1972 ◽  
Vol 104 (12) ◽  
pp. 1977-1983 ◽  
Author(s):  
Roy C. Beckwith
Keyword(s):  
White Spruce ◽  
Coastal Areas ◽  
Early Summer ◽  
Trypodendron Lineatum ◽  
Dendroctonus Rufipennis ◽  
Kenai Peninsula ◽  
Interior Alaska ◽  
Dryocoetes Affaber ◽  
Spruce Stands

AbstractWithin white spruce stands near Fairbanks, Alaska, and on the Kenai Peninsula, Alaska, Dendroctonus rufipennis, Ips spp., and Trypodendron lineatum disperse in late May and early June; other scolytids fly during June and July. Flight in interior Alaska precedes by about 2 weeks that on the Kenai Peninsula. Mean daily temperatures during spring and early summer are generally warmer in the interior than in coastal areas. There was a large increase in the total number of beetles in a thinned area, mostly of Dryocoetes affaber.

ON THE MAXIMUM PRINCIPLE FOR GENERALIZED SOLUTIONS TO THE TRICOMI PROBLEM

2000 ◽  
Vol 02 (04) ◽  
pp. 535-557 ◽  
Author(s):  
DANIELA LUPO ◽  
KEVIN R. PAYNE
Keyword(s):  
Existence And Uniqueness ◽  
Boundary Data ◽  
Minimum Principle ◽  
Generalized Solutions ◽  
Tricomi Problem ◽  
Convexity Condition ◽  
Parabolic Boundary ◽  
The Maximum Principle ◽  
Right Hand ◽  
Maximum Minimum

A maximum/minimum principle for weighted W1,2 solutions to the Tricomi problem with L2 right hand side and homogeneous boundary data is established for normal Tricomi domains. In addition, the existence and uniqueness of such generalized solutions is established for arbitrary L2 right hand sides in normal domains which satisfy a convexity condition near the parabolic boundary points.

Mortality of white spruce during a spruce beetle outbreak on the Kenai Peninsula in Alaska

1983 ◽  
Vol 13 (1) ◽  
pp. 96-101 ◽  
Author(s):  
Richard A. Werner ◽  
Edward H. Holsten
Keyword(s):  
White Spruce ◽  
Permanent Plots ◽  
Kenai Peninsula ◽  
South Central ◽  
Creek Watershed ◽  
Spruce Beetle ◽  
Spruce Stands ◽  
Long Term Impact ◽  
The Impact

White spruce (Piceaglauca (Moench) Voss) stands in the Resurrection Creek watershed in south-central Alaska were infested by spruce bettles, Dendroctonusrufipennis Kirby, between 1974 and 1975. Thirty permanent plots were established within the infested area in 1976 to evaluate the immediate and long-term impact on white spruce stands. Plots were revisited annually for 5 years. Between 1976 and 1980, 29% of all white spruce was killed by spruce beetles. This loss accounted for 59% of the commercial white spruce volume in the watershed. Mortality was greatest in the larger diameter classes during the early part of the infestation, but smaller diameter trees were subsequently attacked as the number of noninfested trees declined. The impact of spruce beetles on structure and species composition of white spruce stands is given along with a discussion of management implications.

Cumulative effects of chronic deer browsing and clear-cutting on regeneration processes in second-growth white spruce stands

2014 ◽  
Vol 329 ◽  
pp. 69-78 ◽  
Author(s):  
Martin Barrette ◽  
Louis Bélanger ◽  
Louis De Grandpré ◽  
Jean-Claude Ruel
Keyword(s):  
White Spruce ◽  
Cumulative Effects ◽  
Deer Browsing ◽  
Clear Cutting ◽  
Second Growth ◽  
Spruce Stands ◽  
Regeneration Processes
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