Dispersal of white spruce seed in mature aspen stands

1998 ◽  
Vol 76 (2) ◽  
pp. 181-188 ◽  
Author(s):  
James D Stewart ◽  
Edward H Hogg ◽  
Patrick A Hurdle ◽  
Kenneth J Stadt ◽  
Peter Tollestrup ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Picea Glauca ◽  
White Spruce ◽  
Simulation Modelling ◽  
Dispersal Distance ◽  
Leaf Fall ◽  
Long Distance ◽  
Artificial Seed ◽  
The Mean

The dispersal of white spruce (Picea glauca (Moench) Voss) seed through trembling aspen (Populus tremuloides Michx.) forests was investigated by releasing artificial seed (confetti) from different heights on a meteorological tower, and, secondly, by observing the distribution of spruce regeneration along transects radiating out from small isolated patches of mature spruce seed trees. Mean dispersal distance of confetti increased with height of release. Before leaf fall of the aspen canopy, most confetti landed close to and in all directions around the tower. After leaf fall, no confetti was observed upwind from the tower and the mean dispersal distance increased, with peak densities occurring at a distance of 15 m in the downwind direction. The rate of decrease in regeneration density with distance from patches of mature, seed-bearing white spruce was much less than that observed during confetti release experiments. Furthermore, regeneration densities were significantly greater in the prevailing downwind direction (toward the east). The results indicate that stronger than average winds, primarily from the northwest, west, and southwest, play a major role in the dispersal of white spruce seed. Simulation modelling of the observed distribution of regeneration suggests that long-distance (>250 m) dispersal may be an important mechanism for the persistence of white spruce in the fire-prone boreal forest of western Canada.Key words: seed dispersal, boreal forest, mixedwood, wind dispersal, artificial seed.

scholarly journals Crown allometry and application of the pipe model theory to white spruce (Picea glauca (Moench) Voss) and aspen (Populus tremuloides Michx.) in the western boreal forest of Canada

2016 ◽  
Vol 46 (2) ◽  
pp. 262-273 ◽  
Author(s):  
Derek F. Sattler ◽  
Philip G. Comeau
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Model Theory ◽  
Picea Glauca ◽  
White Spruce ◽  
Allometric Relationship ◽  
Sapwood Area ◽  
Crown Length ◽  
Pipe Model ◽  
Pipe Model Theory

White spruce (Picea glauca (Moench) Voss) and aspen (Populus tremuloides Michx.) from unmanaged stands in the boreal forest of Alberta, Canada, were examined for two of the main structural assumptions in the process-based model CROBAS: (i) a constant allometric relationship between foliage mass and crown length and (ii) a constant relationship between foliage mass and sapwood area. We evaluated these relationships at both at the whole-crown and within-crown levels. Results indicated that for both species, a constant allometric relationship between foliage mass and crown length was maintained at the whole-crown level over a period exceeding the peak mean annual increment of each species. Within the crowns of spruce, foliage mass accumulated faster near the tree apex as total crown length increased. For aspen, the increase in foliage mass per unit crown length for any section within the crown showed greater similarity to the relationship observed at the whole-crown level. The assumption of a constant relationship between foliage mass and sapwood area at the crown base generally held for spruce but showed considerable variation for any given diameter class. For aspen, this assumption did not appear to be appropriate. For both species, there was more foliage mass per unit sapwood area with increasing height from the ground for nearly all tree size classes. This latter finding was in conflict with the pipe model theory but could not be explained by the hydraulic theory of crown architecture, which predicts a decrease in the ratio of foliage mass to sapwood area with increasing path length.

Nitrogen uptake characteristics for roots of conifer seedlings and common boreal forest competitor species

2003 ◽  
Vol 33 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Ryan D Hangs ◽  
J Diane Knight ◽  
Ken CJ Van Rees
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
N Uptake ◽  
White Spruce ◽  
Jack Pine ◽  
Calamagrostis Canadensis ◽  
Successional Species ◽  
Menten Kinetic

Little is known about the N uptake abilities of competitor species and planted seedlings in the boreal forest. The objective of this study was to determine the Michaelis–Menten kinetic parameters of NH4+ and NO3– for white spruce (Picea glauca (Moench) Voss) and jack pine (Pinus banksiana Lamb.) seedlings, and three competitive common boreal forest early successional species: aspen (Populus tremuloides Michx.), fireweed (Epilobium angustifolium L.), and cala magrostis (Calamagrostis canadensis (Michx.) Beauv.). Uptake kinetics were measured in hydroponic cultures and expressed as maximum uptake (Imax) and ion affinity (Km). The ranking of Imax values (pmol·cm-2·s–1) for NH4+ uptake was calamagrostis (84.6), fireweed (58.1), white spruce (20.7), aspen (12.5), and jack pine (10.9), and for NO3– uptake was calamagrostis (17.7), fireweed (12.5), aspen (5.8), white spruce (4.5), and jack pine (2.1). The ranking of Km values (µM) for NH4+ uptake was calamagrostis (125.9), fireweed (163.8), aspen (205.7), white spruce (217.1), and jack pine (270.5), and for NO3– uptake was calamagrostis (229.9), fireweed (274.6), aspen (336.5), white spruce (344.5), and jack pine (350.5). Calamagrostis exhibited the greatest uptake rates and affinity for NH4+ and NO3–, suggesting that silviculture practices that specifically reduce establishment of this grass should benefit the growth of planted seedlings.

Temporal, spatial, and structural patterns of adult trembling aspen and white spruce mortality in Quebec's boreal forest

2004 ◽  
Vol 34 (2) ◽  
pp. 396-404 ◽  
Author(s):  
Dominic Senecal ◽  
Daniel Kneeshaw ◽  
Christian Messier
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Picea Glauca ◽  
White Spruce ◽  
Trembling Aspen ◽  
Structural Patterns ◽  
Dead Trees ◽  
Mortality Ratio ◽  
Spruce Mortality ◽  
Old Trees

Temporal, spatial, and structural patterns of adult trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) mortality were studied in intact 150-year-old stands in the southwestern boreal forest of Quebec. For both species, mortality decreases (number of dead trees/total number of trees) with distance from the lake edge until 100–150 m, from which point it slightly increases. Strong peaks in mortality were found for 40- to 60-year-old aspen mainly between 1974 and 1992. Such mortality in relatively young aspen is likely related to competition for light from the dominant canopy trees. Also, the recruitment of this young aspen cohort is presumably the result of a stand breakup that occurred when the initial aspen-dominated stand was between 90 and 110 years old. For spruce, strong peaks in mortality were found in 110- to 150-year-old trees and they occurred mainly after 1980. No clear explanation could be found for these peaks, but we suggest that they may be related to senescence or weakening of the trees following the last spruce budworm outbreak. Suppressed and codominant aspen had a much higher mortality ratio than spruce in the same height class, while more surprisingly, no difference in mortality rate was found between dominant trees of the two species. Most spruce trees were found as standing dead, which leads us to reject the hypothesis that windthrow is an important cause of mortality for spruce in our forests.

Radial Growth Decline of White Spruce (Picea glauca) During Hot Summers without Drought: Preliminary Results from a Study Site South of a Boreal Forest Border

2022 ◽  
Author(s):  
Andrei Lapenis ◽  
George Robinson ◽  
Gregory B. Lawrence
Keyword(s):  
New York ◽  
Boreal Forest ◽  
Picea Glauca ◽  
Radial Growth ◽  
Summer Precipitation ◽  
White Spruce ◽  
Southern Limit ◽  
Central New York ◽  
Growth Decline ◽  
Hot Days

Here we investigate the possible<sup></sup> future response of white spruce (Picea glauca) to a warmer climate by studying trees planted 90 years ago near the southern limit of their climate tolerance in central New York, 300 km south of the boreal forest where this species is prevalent. We employed high-frequency recording dendrometers to determine radial growth phenology of six mature white spruce trees during 2013-2017. Results demonstrate significant reductions in the length of radial growth periods inversely proportional to the number of hot days with air temperature exceeding 30 oC. During years with very hot summers, the start of radial growth began about 3 days earlier than the 2013-2017 average. However, in those same years the end of radial growth was also about 17 days earlier resulting in a shorter (70 versus 100 day), radial growth season. Abundant (350-500 mm) summer precipitation, which resulted in soil moisture values of 20-30% allowed us to dismiss drought as a factor. Instead, a likely cause of reduced radial growth was mean temperature that exceeded daily average of 30<sup> o</sup>C that lead to photoinhibition.

scholarly journals Taper Equations for Five Major Commercial Tree Species in Manitoba, Canada

2007 ◽  
Vol 22 (3) ◽  
pp. 163-170 ◽  
Author(s):  
Ryan J. Klos ◽  
G. Geoff Wang ◽  
Qing-Lai Dang ◽  
Ed W. East
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
White Spruce ◽  
Jack Pine ◽  
Volume Estimation ◽  
Trembling Aspen ◽  
Stem Form ◽  
Taper Equation ◽  
Taper Equations

Abstract Kozak's variable exponent taper equation was fitted for balsam poplar (Populus balsamifera L.), trembling aspen (Populus tremuloides Michx.), white spruce (Picea glauca [Moench] Voss), black spruce (Picea mariana [Mill.] B.S.P.), and jack pine (Pinus banksiana Lamb.) in Manitoba. Stem taper variability between two ecozones (i.e., Boreal Shield and Boreal Plains) were tested using the F-test. Regional differences were observed for trembling aspen, white spruce, and jack pine, and for those species, separate ecozone-specific taper equations were developed. However, the gross total volume estimates using the ecozone-specific equations were different from those of the provincial equations by only 2 percent. Although the regional difference in stem form was marginal within a province, a difference of approximately 7 percent of gross total volume estimation was found when our provincial taper equations were compared with those developed in Alberta and Saskatchewan. These results suggest that stem form variation increases with spatial scale and that a single taper equation for each species may be sufficient for each province.

Hexazinone Gridballs™ applied with concurrent underplanting of white spruce in boreal mixedwoods: 7-year results

1986 ◽  
Vol 62 (4) ◽  
pp. 226-232 ◽  
Author(s):  
R. F. Sutton
Keyword(s):  
Picea Glauca ◽  
Ground Surface ◽  
White Spruce ◽  
Separation Distance ◽  
Stem Volume ◽  
Weed Growth ◽  
M 10 ◽  
The Mean ◽  
Boreal Mixedwoods ◽  
Maximum Separation

In mid-June 1978, hexazinone Gridball™ pellets were individually placed on the ground surface in two10-m × 10-m plots at each of two grid spacings in moderate-to-dense, woody weed growth in each of three boreal mixedwood stands in the Chapleau and Manitouwadge areas of Ontario. The rates of application were equivalent to 0.0, 1.4 and 4.2 kg a.i./ha. In these and a similar number of untreated plots, 16 white spruce (Picea glauca [Moench] Voss) were planted centrally in each plot at the same grid spacings used for the Gridballs™ but offset so as to give maximum separation between outplants and herbicide. The main study was supplemented by another to determine safe separation distance. GridballsTM at close spacing very significantly (P 0.01) increased growth of white spruce: at one location, the mean stem volume of spruce 7 years after planting was 438% that of spruce in the no-herbicide treatment; at a second location the comparable value was 503%. The evidence suggests that white spruce may be established in the boreal mixedwoods by underplanting and, concurrently, applying Gridballs™ at 1-m × 1-m spacing.

Within-tree patterns of wood stiffness for white spruce (Picea glauca) and trembling aspen (Populus tremuloides)

2014 ◽  
Vol 44 (2) ◽  
pp. 162-171 ◽  
Author(s):  
Derek F. Sattler ◽  
Philip G. Comeau ◽  
Alexis Achim
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Radial Growth ◽  
Tree Height ◽  
White Spruce ◽  
Vertical Position ◽  
Trembling Aspen ◽  
Mixed Effect ◽  
Cambial Age ◽  
Rate Of Increase

Radial patterns of modulus of elasticity (MOE) were examined for white spruce (Picea glauca (Moench) Voss) and trembling aspen (Populus tremuoides Michx.) from 19 mature, uneven-aged stands in the boreal mixedwood region of northern Alberta, Canada. The main objectives were to (1) evaluate the relationship between pith-to-bark changes in MOE and cambial age or distance from pith; (2) develop species-specific models to predict pith-to-bark changes in MOE; and (3) to test the influences of radial growth, relative vertical height, and tree slenderness (tree height/DBH) on MOE. For both species, cambial age was selected as the best explanatory variable with which to build pith-to-bark models of MOE. For white spruce and trembling aspen, the final nonlinear mixed-effect models indicated that an augmented rate of increase in MOE occurred with increasing vertical position within the tree. For white spruce trees, radial growth and slenderness were found to positively influence maximum estimated MOE. For trembling aspen, there was no apparent effect of vertical position or radial growth on maximum MOE. The results shed light on potential drivers of radial patterns of MOE and will be useful in guiding silvicultural prescriptions.

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

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