Early effects of pre- and post-harvest herbicide application and partial cutting in regenerating aspen – jack pine mixtures in northeastern Ontario

2011 ◽  
Vol 41 (5) ◽  
pp. 1082-1090 ◽  
Author(s):  
Rongzhou Man ◽  
James A. Rice ◽  
G. Blake MacDonald

Silvicultural options to obtain mixtures of broadleaved and conifer tree species in boreal forests remain limited, especially for mixtures of broadleaves and shade-intolerant conifers. In this study, we tested a series of treatment packages that included variation in harvesting pattern, site preparation, renewal treatments, and timing and patterns of tending to establish trembling aspen (Populus tremuloides Michx.) and jack pine (Pinus banksiana Lamb.) mixedwoods in intimate mixtures or spatial mosaics in northeastern Ontario. Preharvest spray resulted in fewer but better growth of aspen suckers compared with postharvest spray, which both reduced sucker density and decreased their vigour. Partial cutting reduced aspen regeneration in both the harvested and leave corridors but did not affect other broadleaved species, in this case predominantly red maple (Acer rubrum L.). After treatment, the rapid development of understory vegetation (shrubs, herbs, and grasses) and regeneration reduced total light transmittance at 0.5 m but had no effect at 4.0 m after 5 years. Future stands will be jack pine dominated following both pre- and post-harvest sprays, despite higher density, more uniform distribution, and better growth of broadleaved regeneration with preharvest spray, but will be balanced broadleaf and conifer mixtures in the partial cut areas.

2015 ◽  
Vol 91 (01) ◽  
pp. 52-59 ◽  
Author(s):  
Rongzhou Man ◽  
G. Blake MacDonald

The conventional plantation approach to regenerating jack pine (Pinus banksiana) after harvesting maximizes pine growth but may reduce wood quality. In this study we examined growth of planted jack pine and natural regeneration after herbicide spraying and partial cutting treatments on a boreal mixedwood site in northeastern Ontario. Treatments were pre-harvest aerial spray, post-harvest ground spray in strips (partial spray), partial cut, and post-harvest aerial broadcast spray; an untreated reference stand was used for comparison. Pre-harvest spray was as effective as partial cutting and post-harvest broadcast spray in suppressing trembling aspen regeneration and providing adequate light for survival and growth of planted jack pine. Ten years after planting, mortality and growth of pines in the pre-harvest treatment were comparable to those in the partial and broadcast spray treatments. Due to vigorous growth of broadleaf species [mostly red maple; (Acer rubrum)], and shade from the residual overstory, jack pine was smallest in the partial cut treatment; however, based on branch size, branch-free stem length and stem taper, wood quality was highest in this treatment. Considering factors important to forest managers such as growth and quality of planted jack pine, treatment costs, and proportion of the harvested blocks allocated to conifer production, the preferred treatment was pre-harvest spray.


2020 ◽  
Vol 9 (4) ◽  
pp. 1-43
Author(s):  
Dustin L. Corr ◽  

Abstract. Scholars, governmental agencies, and concerned citizens are interested in developing empirical predictive models to quantitatively assess the vegetative productivity potentials of reconstructed soils (neo- sols). This research presents equations for a northern Michigan mining region in the Upper Peninsula of Michigan, based on data derived from the National Resources Conservation Service. We employed principal component analysis to develop models to predict the vegetative productivity of corn, corn silage, oats, alfalfa/hay, Irish potatoes, red maple (Acer rubrum L.), white spruce (Picea glauca [Moench] Voss), red pine (Pinus resinosa Aniton), eastern white pine (Pinus strobus L.), jack pine (Pinus banksiana Lamb.), and lilac (Syringa vulgaris L.). Soil attributes that were examined in this research include: available water holding capacity, moist bulk density, % clay, % rock fragments, hydraulic conductivity, % organic matter, soil reactivity, % slope, and topographic position. Four predictive equations based on landscape topography have been developed and are described as an all-mesic woody plant and crop equation, a xeric equation, an equation specific to jack pine, and a wet environment equation. The models were highly significant (p<0.0001) and explained 87.93%, 74.52%, 65.33%, and 87.68% of the variation in site productivity of the respective landscape setting. These equations are intended to assist in efforts to assess the vegetative productivity potentials of reconstructed soils on post-mined landscapes and other disturbed landscapes.


2002 ◽  
Vol 80 (1) ◽  
pp. 93-100 ◽  
Author(s):  
L R Little

Plant competition is expected to produce an overdispersed spatial pattern relative to the initial pattern of individuals. The spatial patterns of two boreal forest tree species, Populus tremuloides Michx. (trembling aspen) and Pinus banksiana Lamb. (jack pine), were examined for evidence of intraspecific and interspecific competition. Data consisting of species, position, and age of tree stems were obtained from a 21-year-old, 40 m × 30 m postfire area of boreal forest in northern Alberta, Canada. Tree stems were mapped and classified according to size (greater or less than 5 cm in diameter at ground height) and species. A variation on the random mortality hypothesis was used to detect overdispersed patterns indicative of competitive interactions. This was done by comparing the size of neighbouring stems with those expected when the size or "success" of a stem occurred randomly. The results showed roughly two scales of pattern. First, large seed-regenerating jack pine neighboured each other more often than expected, but jack pine and trembling aspen neighboured each other less than expected. Second, although the large jack pine appeared to be clustered as neighbours, they tended to associate at distances farther than expected. These results show little evidence of density-dependence patterns in the species at the site, and the interspecific association between jack pine and trembling aspen could be indicative of a heterogeneous habitat.Key words: triangulation, size variability, Pinus banksiana, Populus tremuloides, jack pine, trembling aspen.


Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 370
Author(s):  
Holly D. Deighton ◽  
Frederick Wayne Bell ◽  
Nelson Thiffault ◽  
Eric B. Searle ◽  
Mathew Leitch ◽  
...  

We assessed 27 indicators of plant diversity, stand yield and individual crop tree responses 25 years post-treatment to determine long-term trade-offs among conifer release treatments in boreal and sub-boreal forests. This research addresses the lack of longer-term data needed by forest managers to implement more integrated vegetation management programs, supporting more informed decisions about release treatment choice. Four treatments (untreated control, motor-manual brushsaw, single aerial spray, and complete competition removal) were established at two jack pine (Pinus banksiana Lamb.) sites in Ontario, Canada. Our results suggest that plant diversity and productivity in boreal jack pine forests are significantly influenced by vegetation management treatments. Overall, release treatments did not cause a loss of diversity but benefitted stand-scale yield and individual crop tree growth, with maximum benefits occurring in more intensive release treatments. However, none of the treatments maximized all 27 indicators studied; thus, forest managers are faced with trade-offs when choosing treatments. Research on longer term effects, ideally through at least one rotation, is essential to fully understand outcomes of different vegetation management on forest diversity, stand yield, and individual crop tree responses.


2017 ◽  
Vol 35 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Darby McGrath ◽  
Jason Henry ◽  
Ryan Munroe ◽  
Erin Agro

Abstract This experiment investigated the effect of different plug-tray cell designs on root development of red maple (Acer rubrum), red oak (Quercus rubra), and quaking aspen (Populus tremuloides) seedlings. In April of 2015, seeds of each species were sown into three plug trays with different substrate volumes and grown for 17 weeks. Two trays had permeable walls for air-pruning, one with vertical ribs and one without. The third tray had impermeable plastic cell walls. Harvested seedlings were analyzed for root dry weight, length, volume, surface area and number of deflected roots. Root length per volume was highest in the impermeable-walled tray for red maple and quaking aspen. The total numbers of deflected root systems were higher for all species in the impermeable-walled tray. Seedlings grown in the air-pruning trays had smaller proportions of deflected root masses. Greater substrate volume did not influence root deflection development. The air-pruning tray without vertical ribs had the lowest total number of root masses with misdirected roots and lower proportions of root masses with misdirected roots for all species. These results indicate that improved root architecture in root-air pruning tray designs is achievable in tree propagation; however, vertical plastic structures in air-pruning trays can still cause root deflections. Index words: Deflected roots, air-pruning, seedling, propagation, plugs, root architecture. Species used in the study: red maple (Acer rubrum L.); red oak (Quercus rubra L.); quaking aspen (Populus tremuloides Michx.).


2007 ◽  
Vol 22 (3) ◽  
pp. 163-170 ◽  
Author(s):  
Ryan J. Klos ◽  
G. Geoff Wang ◽  
Qing-Lai Dang ◽  
Ed W. East

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.


Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 682
Author(s):  
Feng Xu ◽  
Maryamsadat Vaziriyeganeh ◽  
Janusz J. Zwiazek

Responses of trembling aspen (Populus tremuloides), jack pine (Pinus banksiana), and white spruce (Picea glauca) seedlings to root zone pH ranging from 5 to 9 were studied in sand culture in the presence of two mineral nutrition levels. After eight weeks of treatments, effects of pH on plant dry weights varied between the plant species and were relatively minor in white spruce. Higher nutrient supply significantly increased dry weights only in trembling aspen subjected to pH 5 treatment. There was little effect of pH and nutrition level on net photosynthesis and transpiration rates in white spruce and jack pine, but net photosynthesis markedly declined in aspen at high pH. Chlorophyll concentrations in young foliage decreased the most in trembling aspen and jack pine. The effects of high pH treatments on the concentrations of Mg, P, Ca, Mn, Zn, and Fe in young foliage varied between the plant species with no significant decreases of Fe and Zn recorded in trembling aspen and white spruce, respectively. This was in contrast to earlier reports from the studies carried out in hydroponic culture. The sand culture system that we developed could be a more suitable alternative to hydroponics to study plant responses to pH in the root zone. Plant responses to high pH appear to involve complex events with a likely contribution of nutritional effects and altered water transport processes.


1988 ◽  
Vol 64 (4) ◽  
pp. 315-319 ◽  
Author(s):  
Z. Chrosciewicz

An experimental burn in conjunction with a seed-tree system was successful in regenerating jack pine (Pinus banksiana Lamb.) on a fresh to somewhat moist upland, loamy till, cutover site in central Saskatchewan. About 20 well-formed, uniformly spaced seed trees per hectare were left standing during timber harvest. The ignition of logging slash was carried out under preselected weather and fuel conditions so that favorable seedbeds and adequate seed dispersal from the seed trees were produced. Four growing seasons after burning, jack pine stocking by 4-m2 quadrats was 90% with 12 195 seedlings/ha. Aspen (Populus tremuloides Michx.), to a lesser degree black spruce (Picea mariana [Mill.] B.S.P.), and other companion tree species also regenerated with the pine. Various seedbed and regeneration characteristics as well as height growth rates are discussed. Key words: Pinus banksiana, slash burning, seed-tree system, forest regeneration, growth rates, central Saskatchewan.


2010 ◽  
Vol 40 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Xavier Cavard ◽  
Yves Bergeron ◽  
Han Y.H. Chen ◽  
David Paré

This study investigates the potential of mixed forest stands as better aboveground carbon sinks than pure stands. According to the facilitation and niche complementarity hypotheses, we predict higher carbon sequestration in mature boreal mixedwoods. Aboveground carbon contents of black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.) and trembling aspen ( Populus tremuloides Michx.) mixtures were investigated in the eastern boreal forest, whereas jack pine ( Pinus banksiana Lamb.) and trembling aspen were used in the central boreal forest. No carbon gain was found in species mixtures; nearly pure trembling aspen stands contained the greatest amount of aboveground carbon, black spruce stands had the least, and mixtures were intermediate with amounts that could generally be predicted by linear interpolation with stem proportions. These results suggest that for aspen, the potentially detrimental effect of spruce on soils observed in other studies may be offset by greater light availability in mixtures. On the other hand, for black spruce, the potentially beneficial effects of aspen on soils could be offset by greater competition by aspen for nutrients and light. The mixture of jack pine and trembling aspen did not benefit any of these species while inducing a loss in trembling aspen carbon at the stand level.


2013 ◽  
Vol 43 (3) ◽  
pp. 224-233 ◽  
Author(s):  
Marcel Prévost ◽  
Daniel Dumais

Estimating residual tree survival and growth is crucial for evaluating the overall merit of partial harvesting. In this case study, we present the effects of different cutting intensities (0%, 40%, 50%, and 60% of merchantable (diameter at breast height ≥ 9.1 cm) basal area (BA)) on the response of residual trees in two mixed yellow birch (Betula alleghaniensis Britt.) – conifer stands in eastern Quebec, Canada. Primarily aimed at promoting regeneration establishment, the experiment was conducted in two sites 90 km apart (Armagh and Duchesnay), each one containing four replicates of treatments in a randomized block design. Mortality after cutting decreased with increasing BA removal, but losses were two to three times higher at Armagh (62–138 stems/ha) than at Duchesnay (22–88 stems/ha). Loss of conifer stems involved primarily balsam fir (Abies balsamea (L.) Mill.) under natural conditions (control), whereas fir and red spruce (Picea rubens Sarg.) were equally affected in partial cuts. Red maple (Acer rubrum L.) and paper birch (Betula papyrifera Marsh.) were lost regardless of treatment. As a whole, growth in merchantable BA increased with cutting intensity. Uniform partial cuts produced good BA growth response from conifers at Armagh (0.27–0.28 m2·ha−1·year−1) and from hardwoods at Duchesnay (0.16–0.25 m2·ha−1·year−1), whereas BA growth was negligible for both species groups in the control. We examine the role of species composition and stand structure before cutting in the response of residual trees.


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