scholarly journals Birch (Betula papyrifera) × white spruce (Picea glauca) interactions in mixedwood stands: implications for management

2013 ◽  
Vol 59 (No. 4) ◽  
pp. 137-149 ◽  
Author(s):  
Ch.D.B. Hawkins ◽  
A. Dhar
Keyword(s):  
Regression Analysis ◽  
Picea Glauca ◽  
Mixed Model ◽  
Basal Area ◽  
White Spruce ◽  
Betula Papyrifera ◽  
Vegetation Control ◽  
Mixed Model Anova ◽  
Paper Birch ◽  
The Impact

Current British Columbia forest regulations drive the regeneration management towards pure conifer stands rather than remaining in a mixed-species condition. This approach may result in unnecessary vegetation control. The main objective of this investigation was to study the impact of variable paper birch densities on white spruce growth in 15&ndash;20 years old stands for management implications. Regression analysis was used to examine the effect of birch density and two competition indices to predict spruce growth. A mixed model ANOVA showed that spruce mean annual DBH and basal area increment differed significantly among sites and density. From the regression analysis it appears that birch density up to 4,000 stems&middot;ha<sup>&ndash;1</sup> had no significant influence on spruce growth which is much higher than the current BC reforestation guideline (1,000 stems&middot;ha<sup>&ndash;1</sup> broadleaves). Similarly, birch relative density index (RDI) had to exceed 3 to affect spruce DBH growth significantly on all sites except one. On most sites, spruce had a larger DBH than birch. Our results also suggest that rather than following the current broadcast approach to vegetation management, a targeted approach could enhance forest productivity and stand diversity. &nbsp;

Influences of paper birch competition on growth of understory white spruce and subalpine fir following spacing

2003 ◽  
Vol 33 (10) ◽  
pp. 1962-1973 ◽  
Author(s):  
Philip G Comeau ◽  
Jian R Wang ◽  
Tony Letchford
Keyword(s):  
Picea Glauca ◽  
Volume Growth ◽  
Basal Area ◽  
White Spruce ◽  
Light Transmittance ◽  
Height Increment ◽  
Growth Responses ◽  
Subalpine Fir ◽  
Volume Increment ◽  
Paper Birch

Five years after spacing a young, 11 m tall paper birch (Betula papyrifera Marsh.) stand, we examine relationships between growth of understory white spruce (Picea glauca (Moench) Voss), subalpine fir (Abies lasiocarpa (Hook.) Nutt.), and level of birch retention. Our objectives were to evaluate the effectiveness of selected measures of competition for estimating the effects of the residual birch and to evaluate the influence of residual birch densities on growth responses of naturally regenerated subalpine fir and white spruce. Basal area of Scouler willow (Salix scouler iana Barratt) and birch were found to effectively predict light transmittance (diffuse noninterceptance). The best models for predicting 4-year volume growth of subalpine fir and white spruce incorporate initial crown volume of the subject trees and transmittance as independent variables. Lorimer's index and Hegyi's index gave similar results to those obtained using basal area and transmittance, suggesting that there is little benefit in including measurements of proximity in a competition index. For both species, the correlation between basal area increment and light was substantially stronger than observed for volume increment. However, height increment of both subalpine fir and spruce was only weakly correlated with measured light levels. The ratio of height increment to volume increment decreased with both increasing initial height and transmittance for subalpine fir and white spruce.

Effet d'une coupe d'ensemencement et du milieu de germination sur la régénération des sapinières boréales riches de seconde venue du Québec

2000 ◽  
Vol 76 (4) ◽  
pp. 643-652 ◽  
Author(s):  
Patricia Raymond ◽  
Jean-Claude Ruel ◽  
Marius Pineau
Keyword(s):  
Picea Glauca ◽  
Forest Cover ◽  
Seedling Survival ◽  
Mineral Soil ◽  
Abies Balsamea ◽  
Basal Area ◽  
White Spruce ◽  
Balsam Fir ◽  
Paper Birch ◽  
Cutting System

Stand regeneration failures, sometimes observed in rich second growth balsam fir stands, prompted a study in 1991 to assess the effects of the shelterwood cutting system on regeneration of balsam fir (Abies balsamea (L.) Mill.), white spruce (Picea glauca (Moench) Voss) and paper birch (Betula papyrifera Marsh). The factorial experiment design (split-plot) includes forest cover reduction (0% and 25% of basal area) in main plots and germination substrate (mineral soil, litter removed and control) in subplots. Results of five growing seasons showed that germination substrate was the main factor determining first-year seedling establishment, and that cover reduction became important for seedling survival and long-term establishment of the three species. A 25% canopy reduction combined with mineral seedbed treatment resulted in the best regeneration densities of the three species. Thus far, the results demonstrate the importance of combining humus disturbance to seed cutting in order to achieve regeneration goals set for the future stand. Key words: shelterwood cutting system, balsam fir, white spruce, paper birch, regeneration, seed cutting, germination substrate

The role of information structure in the instantiation of objects: Evidence from Amazonian Spanish

2020 ◽  
Vol 13 (1) ◽  
pp. 219-245
Author(s):  
Rosa Vallejos ◽  
Evelyn Fernández-Lizárraga ◽  
Haley Patterson
Keyword(s):  
Regression Analysis ◽  
Information Structure ◽  
Mixed Model ◽  
Linguistic Variables ◽  
Social Variables ◽  
Null Objects ◽  
The Impact ◽  
Role Of Information ◽  
Activation Status

AbstractThis study analyzes the instantiation of objects in Peruvian Amazonian Spanish (PAS) discourse in two communities with distinct linguistic contexts. We examine the impact of two social variables (gender and place) and nine linguistic variables (transitivity, animacy, definiteness, anaphora function, anaphora expression, cataphora function, cataphora expression, activation, topic persistence) on the speech of eight participants. Our findings indicate that null instantiation in PAS is pervasive, occurring with a range of verb lexemes. While neither gender nor place are significant predictors of null objects, various linguistic variables contribute to the instantiation of objects. The five significant variables as determined by a mixed model regression analysis include the following: animacy, definiteness, anaphora expression, cataphora expression, and activation status. Several findings are consistent with previous research (e. g. human and definite referents disfavor null objects), while other results differ (e. g. PAS propositions disfavor null objects). Activation status and anaphora expression are the most significant predictors of null objects in PAS. In particular, highly accessible referents in discourse and anaphoric null objects favored null objects in subsequent clauses. Thus, the results in the present study demonstrate the pivotal role of information structure in object instantiation, furthering the discussion on syntax-discourse interplay phenomena.

Meta-analysis of understory white spruce response to release from overstory aspen

2004 ◽  
Vol 80 (6) ◽  
pp. 694-704 ◽  
Author(s):  
Rongzhou Man ◽  
Ken J Greenway
Keyword(s):  
Growth Response ◽  
Mixed Model ◽  
Polynomial Regression ◽  
Meta Analysis ◽  
Basal Area ◽  
Tree Height ◽  
White Spruce ◽  
Response Ratio ◽  
Mixed Effect ◽  
Individual Tree

Meta-analysis was used to summarize the research results on the growth response of understory white spruce to release from overstory aspen from different studies available from published and unpublished sources. The data were screened for the suitability for meta-analysis. Treatment effect sizes were calculated using response ratio from mean cumulative increments of released and control trees since release in height, diameter, and volume and modeled using a polynomial mixed effect regression procedure. Predictor variables include linear, quadratic, and cubic components of three independent variables — initial tree height, number of years after release, and residual basal area at release — and their linear interactions. Models with a reasonable predictive power were developed for height, diameter, and volume response, but no significant model was identified for survival. The models developed in this study can be applied to predict the growth response of understory white spruce to release, based on the growth of unreleased control trees, initial tree height, residual basal area at release, and time since release. The individual tree prediction can be easily scaled up to stand level if residual tree density and distribution is known. Key words: meta-analysis, boreal mixedwood, mixed model, polynomial regression, response ratio, growth, survival

Survival and growth response of white spruce stock types to site preparation in Alaska

2011 ◽  
Vol 41 (4) ◽  
pp. 793-809 ◽  
Author(s):  
Andrew Youngblood ◽  
Elizabeth Cole ◽  
Michael Newton
Keyword(s):  
Picea Glauca ◽  
Seedling Survival ◽  
White Spruce ◽  
Site Preparation ◽  
Herbicide Application ◽  
Preparation Methods ◽  
Vegetation Control ◽  
Survival And Growth ◽  
Stock Types ◽  
Bare Root

To identify suitable methods for reforestation, we evaluated the interacting effects of past disturbance, stock types, and site preparation treatments on white spruce (Picea glauca (Moench) Voss) seedling survival and growth across a range of sites in Alaska. Replicated experiments were established in five regions. At each site, two complete installations differed in time since disturbance: “new” units were harvested immediately before spring planting and “old” units were harvested at least 3 years before planting. We compared mechanical scarification before planting, broadcast herbicide application during the fall before planting, and no site preparation with 1-year-old container-grown seedlings from two sources, 2-year-old bare-root transplants from two sources, and 3-year-old bare-root transplants. Seedlings were followed for 11 years on most sites. Based on meta-analyses, seedling survival increased 10% with herbicide application and 15% with mechanical scarification compared with no site preparation. Scarification and herbicide application increased seedling height by about 28% and 35%, respectively, and increased seedling volume by about 86% and 195%, respectively, compared with no site preparation. Soil temperature did not differ among site preparation methods after the first 7 years. Results suggest that white spruce stands may be successfully restored through a combination of vegetation control and use of quality planting stock.

Regenerating white spruce, paper birch, and willow in south-central Alaska

1999 ◽  
Vol 29 (7) ◽  
pp. 993-1001 ◽  
Author(s):  
E C Cole ◽  
M Newton ◽  
A Youngblood
Keyword(s):  
Picea Glauca ◽  
Volume Growth ◽  
White Spruce ◽  
Site Preparation ◽  
Stem Volume ◽  
Dendroctonus Rufipennis ◽  
Relative Growth Rates ◽  
South Central ◽  
Interior Alaska ◽  
Paper Birch

The current spruce bark beetle (Dendroctonus rufipennis Kirby) epidemic in interior Alaska is leaving large expanses of dead spruce with little spruce regeneration. Many of these areas are habitat for moose (Alces alces). To establish spruce regeneration and improve browse production for moose, paper birch (Betula papyrifera Marsh), willow (Salix spp.), and three stocktypes (plug+1 bareroot, and 1+0 plugs from two nurseries) of white spruce (Picea glauca (Moench) Voss) were planted in freshly cutover areas on Fort Richardson, near Anchorage. Four vegetation-management treatments were compared: broadcast site preparation with herbicides, banded site preparation with herbicides, mechanical scarification, and untreated control. Spruce seedlings had the greatest growth in the broadcast site preparation treatment (p < 0.01). Stocktype was the most important factor in spruce growth, with bareroot transplant seedlings being the tallest and largest 5 years after planting (p < 0.001). In the first 3 years, relative stem volume growth was greater for plug seedlings than for bareroot seedlings (p < 0.001). By year 4, relative growth rates were similar among all stocktypes. Treatment effects for paper birch and willow were confounded by moose browsing. Results indicate spruce can be regenerated and moose browse enhanced simultaneously in forests in interior Alaska.

scholarly journals Contrasting Release Approaches for a Mixed Paper Birch (Betula papyrifera)–Quaking Aspen (Populus tremuloides) Stand

2008 ◽  
Vol 25 (3) ◽  
pp. 124-132 ◽  
Author(s):  
Eric K. Zenner ◽  
Klaus J. Puettmann
Keyword(s):  
Populus Tremuloides ◽  
Basal Area ◽  
Complete Removal ◽  
Quaking Aspen ◽  
Betula Papyrifera ◽  
Mixed Stands ◽  
Early Release ◽  
Paper Birch ◽  
Area And Volume

Abstract Early release from competitors can be used to influence the species composition, quality, and rate of development of young stands. Release strategies can vary in intensity, ranging from complete removal of competitors and infrequent future entries (early, heavy, infrequent [EHI]) to lighter entries that are repeated more frequently (early, light, often [ELO]). It is unclear, however, which strategy is more successful for producing high-quality birch sawtimber (Betula papyrifera Marsh.) in mixed stands with aspen (Populus tremuloides Michx.). We evaluated the effects of various release intensities on the growth and mortality of a 16–18-ft-tall natural aspen–paper birch stand in Minnesota following density reductions from 1,500–3,000 trees ac−1 (trees per acre [TPA]) to 750 (ELO750), 500 (EHI500), and 250 (EHI250) TPA. After 6 years, paper birch was overtopped by aspen and contributed only 14% of basal area in control plots, but it occupied all diameter classes and contributed 77–87% of basal area in release plots. The basal area and volume of all paper birch and of only paper birch crop trees (100 largest TPA) were highest in lightly released ELO750 and lowest in control plots. Growth of mean quadratic diameter, basal area, and volume of paper birch was 2–3 times higher in release plots but independent of release intensity. Early release is necessary to maintain paper birch dominance, but there is no short-term advantage among treatment intensities. Long-term growth simulations using the Forest Vegetation Simulator suggest that merchantable timber production was unaffected by release strategy but that the EHI250 strategy produced the most birch sawtimber (40 times as much as in ELO750).

Stem- and stand-level growth and mortality following partial cutting in eastern boreal poplar – white spruce stands

2019 ◽  
Vol 49 (5) ◽  
pp. 463-470 ◽  
Author(s):  
Suzanne Brais ◽  
Brian D. Harvey ◽  
Arun K. Bose
Keyword(s):  
Growth Rates ◽  
Picea Glauca ◽  
Basal Area ◽  
Natural Disturbance ◽  
White Spruce ◽  
Primary Objective ◽  
Post Treatment ◽  
Tree Level ◽  
Growth Responses ◽  
Partial Cutting

Variable retention (VR) and partial cutting are both considered important silvicultural tools of natural disturbance or ecosystem based forest management approaches. Partial harvesting differs from VR in that post-treatment growth responses and stand regeneration are the primary objective rather than the maintenance of biodiversity. This partial cutting study is undertaken in mixed poplar (Populus spp.) – white spruce (Picea glauca (Moench) Voss) stands in the eastern Canadian boreal mixedwood forest. It compares, at the tree level, absolute growth rates (AGR) and relative growth rates (RGR) of basal area (BA) and stem survival; and at the stand level, it also compares absolute BA growth, mortality, and sapling density 10 years following treatment. The completely randomized experiment was established with four intensities of partial cutting (0, 50%, 65%, and 100% of poplar BA). All partial cutting intensities had a significant and similar positive effect on AGR of residual spruce stems. Complete poplar removal resulted not only in the highest increase in RGR of suppressed and intermediate spruce stems, but also in higher spruce mortality. Removal of 50% of the initial poplar stand BA provided the best trade-off between positive residual stem growth of spruce and poplar and limited post-treatment mortality.

Predicting natural regeneration of white spruce in boreal mixedwood understories

2001 ◽  
Vol 77 (6) ◽  
pp. 1006-1013 ◽  
Author(s):  
James D. Stewart ◽  
Simon M. Landhäusser ◽  
Kenneth J. Stadt ◽  
Victor J. Lieffers
Keyword(s):  
Picea Glauca ◽  
Mineral Soil ◽  
Clay Fraction ◽  
Basal Area ◽  
White Spruce ◽  
Height Growth ◽  
Feather Moss ◽  
Moss Cover ◽  
Rotten Wood ◽  
Soil Clay

Successful mixedwood management in the boreal forest of Alberta requires better knowledge of the occurrence and success of natural white spruce regeneration. In this study we developed statistical models to predict the natural establishment and height growth of understory white spruce (Picea glauca (Moench) Voss) in the boreal mixedwood forest in Alberta using data from 148 provincial permanent sample plots, supplemented by measurements of the amount and height growth of regenerating white spruce, and the amount and type of available substrate. A discriminant model correctly classified 73% of the sites as to presence or absence of a white spruce understory based on the amount of spruce basal area, rotten wood, ecological nutrient regime, soil clay fraction and elevation, although it explained only 30% of the variation in the data. On sites with a white spruce understory, a regression model related the abundance of regeneration to rotten wood cover, spruce basal area, pine basal area, soil clay fraction, and grass cover (R2 = 0.36). About half of the seedlings surveyed grew on rotten wood, and only 3% on mineral soil, and seedlings were 10 times more likely to have established on these substrates than on litter. Exposed mineral soil was rare, covering only 0.3% of the observed transect area, rotten wood covered 4.5%, and litter/undisturbed forest floor covered the remainder. The regression models developed for average relative height growth rate included feather moss cover, stand age and birch basal area for seedlings ≤ 1 m (R2 = 0.23), and feather moss cover, elevation, other moss cover and soil clay fraction for seedlings between 1 m and 3 m (R2 = 0.27). Key words: Picea glauca, seedling establishment, seedbeds, site factors, coarse woody debris, predictive models, mixedwood management

scholarly journals Lodgepole Pine and White Spruce Establishment After Glyphosate and Fertilizer Treatments of Grassy Cutover Forest Land.

1979 ◽  
Vol 55 (3) ◽  
pp. 102-105 ◽  
Author(s):  
D. G. Blackmore ◽  
Wm. G. Corns
Keyword(s):  
Picea Glauca ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
White Spruce ◽  
Forest Land ◽  
Vegetation Control ◽  
Calamagrostis Canadensis ◽  
Pine Seedlings ◽  
One Year ◽  
Spring Planting

Perennial herbaceous vegetation, mainly marsh reed grass, (Calamagrostis canadensis (Michx) Beauv.), was sprayed with glyphosate on the day before planting one-year-old plugs of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) and white spruce (Picea glauca (Moench) Voss) on cutover forest land north of Edson, Alberta. Spraying at 4.5 kg ai/ha, included spot and strip applications in June 1976, compared with unsprayed scalps and controls. At the same time, all treatments were repeated plus a 9 g, 22-8-2 fertilizer tablet for each seedling. Another experiment at the same site, begun on August 1, 1976, compared scalp, unfertilized control and glyphosate strip treatments, followed by planting of pine seedlings the day after spraying 4.5 kg ai/ha glyphosate. An adjacent experiment, also commenced on August 1, included dosages of 1.1 to 5.6 kg ai/ha with planting of pine seedlings in 4.5 kg/ha and in control plots in May 1977. August application of 2.2 kg/ha provided excellent initial vegetation control, as effective as the larger amounts applied at that time, and was superior during the first 12 months to 4.5 kg/ha applied in June. Twenty-six months after the spring planting new shoot growth of fertilized pine in the glyphosate strips was statistically significantly greater than that for all other treatments and growth in fertilized scalps was also very good. At the same time leader growth of spruce in fertilized scalps was significantly greater than that for other treatments but growth in glyphosate strips did not exceed that of unfertilized controls. Contrary to results of spring planting, there was marked injury and mortality of pine planted in August in glyphosate plots which had been sprayed on the preceding day. Seedlings planted in glyphosate-treated strips nine months after the August spraying exceeded the growth of control plants but not until the year after they were planted.

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