Recent climatic drying leads to age-independent growth reductions of white spruce stands in western Canada

2017 ◽  
Vol 23 (12) ◽  
pp. 5297-5308 ◽  
Author(s):  
Edward H. Hogg ◽  
Michael Michaelian ◽  
Trisha I. Hook ◽  
Michael E. Undershultz
1979 ◽  
Vol 9 (4) ◽  
pp. 443-448 ◽  
Author(s):  
D. F. W. Pollard ◽  
C. C. Ying

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.


2015 ◽  
Vol 358 ◽  
pp. 98-107 ◽  
Author(s):  
Seung-Il Lee ◽  
John R. Spence ◽  
David W. Langor ◽  
Jaime Pinzon

2012 ◽  
Vol 42 (8) ◽  
pp. 1566-1576 ◽  
Author(s):  
Derek Joseph Lawrence ◽  
N. Luckai ◽  
W.L. Meyer ◽  
C. Shahi ◽  
A.J. Fazekas ◽  
...  

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.


1999 ◽  
Vol 75 (3) ◽  
pp. 505-513 ◽  
Author(s):  
Rongzhou Man ◽  
Victor J. Lieffers

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


1995 ◽  
Vol 25 (9) ◽  
pp. 1455-1465 ◽  
Author(s):  
Shongming Huang ◽  
Stephen J. Titus

Based on a data set from 164 permanent sample plots, an age-independent individual tree diameter increment model is presented for white spruce (Piceaglauca (Moench) Voss) grown in the boreal mixed-species stands in Alberta. The model is age independent in that it does not explicitly require tree or stand age as input variables. Periodic diameter increment is modelled as a function of tree diameter at breast height, total tree height, relative competitiveness of the tree in the stand, species composition, stand density, and site productivity. Because data from permanent sample plots are considered time series and cross sectional, diagnostic techniques were applied to identify the model's error structure. Appropriate fit based on the identified error structure was accomplished using weighted nonlinear least squares with a first-order autoregressive process. Results show that (1) all model parameters are significant at α = 0.05 level, and (2) the plot of studentized residuals against predicted diameter increment shows no consistent underestimate or overestimate for diameter increment. The model was also tested on an independent data set representing the population on which it is to be used. Results show that the average prediction biases are not significant at α = 0.05 level, indicating that the model appropriately describes the data and performs well when predictions are made.


1972 ◽  
Vol 104 (12) ◽  
pp. 1977-1983 ◽  
Author(s):  
Roy C. Beckwith

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.


PLoS ONE ◽  
2013 ◽  
Vol 8 (10) ◽  
pp. e77607 ◽  
Author(s):  
Jian-Guo Huang ◽  
Kenneth J. Stadt ◽  
Andria Dawson ◽  
Philip G. Comeau

2017 ◽  
Vol 233 ◽  
pp. 133-142 ◽  
Author(s):  
Lei Chen ◽  
Jian-Guo Huang ◽  
Kenneth J. Stadt ◽  
Philip G. Comeau ◽  
Lihong Zhai ◽  
...  

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