scholarly journals Effect of Browsing, Seedbed, and Competition on the Development of Yellow Birch Seedlings in High-Graded Stands

2009 ◽  
Vol 26 (3) ◽  
pp. 99-105 ◽  
Author(s):  
Jean-Gabriel Elie ◽  
Jean-Claude Ruel ◽  
Jean-Martin Lussier
Keyword(s):  
Major Effect ◽  
Growth Potential ◽  
Betula Alleghaniensis ◽  
Yellow Birch ◽  
Growth And Survival ◽  
Early Seedling ◽  
Survival And Growth ◽  
Further Development ◽  
Very High ◽  
Mixedwood Stands

Abstract Many hardwood or mixedwood stands of northeastern North America have been high graded in the past and need restoration treatments to bring them back to an acceptable level of production. Even when early seedling establishment can be secured, further development may be compromised bymany factors. This study looks at the effect of seedbed, browsing, and competition on the growth and survival of yellow birch (Betula alleghaniensis Britt.) seedlings that became established after a brushing and scarification treatment applied in high-graded mixedwood stands of Quebec,Canada. The seedbed types studied include 1-m-wide scarified patches, 2-m-wide scarified patches, and mounds. Browsing impact was assessed by placing fences around half of the plots. Half of the plots were released from competing vegetation. Browsing by hare (Lepus americanus) was seenas a major factor controlling seedling development between 3 and 6 years after scarification. It reduced both survival and growth and obscured the effect of other factors. In the absence of browsing, competition had a major effect on mounds but not on scarified patches. Mounds were found tohave the best growth potential when competition and browsing were controlled. The scarified patches had the best growth when competition and browsing were allowed. Even though mortality was somewhat higher on scarified patches, initial densities were very high and still provide more seedlingsthan required.

scholarly journals Genetic Variation and Climatic Impacts on Survival and Growth of White Spruce in Alberta, Canada

2007 ◽  
Vol 56 (1-6) ◽  
pp. 117-127 ◽  
Author(s):  
D. M. Rweyongeza ◽  
R.-C. Yang ◽  
N. K. Dhir ◽  
L. K. Barnhardt ◽  
C. Hansen
Keyword(s):  
Genetic Variation ◽  
Intraclass Correlation ◽  
White Spruce ◽  
Forest Tree ◽  
Growth Potential ◽  
Mean Annual Precipitation ◽  
Phenotypic Variance ◽  
Moisture Index ◽  
Growth And Survival ◽  
Survival And Growth

Abstract Because climate has the greatest effect in determining the genetic structure of forest tree species, climatic variables with large effects on growth and survival need to be identified. This would enable proper matching of tree populations to planting sites in the present and future climates. We analysed 24-year survival (S24), height (H24) and diameter (D24) from a series of white spruce provenance trials with 46 populations and 8 test sites in Alberta, Canada. We determined: (1) the amount and pattern of genetic variation, (2) the response of populations to climatic transfer and (3) the potential effects of climate change (2030-2039) on H24 and S24 of the species in Alberta. We found that: (1) using the intraclass correlation, the between-population genetic variance was 10.6% (H24) and 6.6% (D24) of the betweenpopulation phenotypic variance across sites, (2) three climatic white spruce regions exist in Alberta within which variation in growth potential is strongly clinal, (3) the annual moisture index (AMI) expressed as a ratio of degree days above 5°C (GDD) and mean annual precipitation (MAP) was the major determinant of survival and growth at the test sites, (4) we found that at the level of AMI predicted for the 2030-2039 period, survival and growth would decline substantially in the continental part (northern and central) of Alberta where drought already exists. However, during the same period, survival and growth would increase substantially in the foothills and Rocky Mountains region where growth is currently limited by low GDD due to a short growing season.

scholarly journals Assessing Post-Harvest Regeneration in Northern Hardwood and Mixedwood Stands: Evolution of Species Composition and Dominance within 15-Year-Old Group Selection and Patch Cutting

Forests ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 742 ◽  
Author(s):  
Simon Bilodeau-Gauthier ◽  
Steve Bédard ◽  
François Guillemette
Keyword(s):  
Group Selection ◽  
Sugar Maple ◽  
Experimental Studies ◽  
Early Years ◽  
Maximum Height ◽  
Betula Alleghaniensis ◽  
Yellow Birch ◽  
Northern Hardwood ◽  
Post Harvest ◽  
Mixedwood Stands

Multi-cohort forest management in northern hardwood stands may well be the best way to successfully regenerate tree species of intermediate shade tolerance, such as yellow birch (Betula alleghaniensis Britt.). The creation of large enough gaps in the canopy favors increased light availability within the opening, while soil scarification provides suitable germination seedbeds. Evidence of these methods’ success nonetheless remains mostly the purview of experimental studies rather than operational tests. In Quebec, Canada, the multi-cohort methods promoted include group selection cutting and patch cutting. The present study tested their implementation at an operational scale and over a large territory in both hardwood-dominated and mixedwood stands. We assessed their efficacy in promoting natural regeneration of commercial hardwood trees, notably yellow birch and sugar maple (Acer saccharum Marsh.). We conducted regeneration surveys at 2, 5, 10, and 15 years after harvest. Overall, group selection and patch cuttings were successful in regenerating the target species. Yellow birch, for instance, showed a mean stocking around 60% and a mean sapling density around 3400 stems ha−1 after 15 years. We compared several variables for measuring regeneration in early years, and found that the relative abundance, the stocking based on one stem per sampling unit, and the mean maximum height were good predictors of the relative presence of yellow birch and sugar maple in 15-year-old canopy openings. Using smaller sampling units (6.25 m2 rather than 25 m2) and waiting until year 5 may be more useful for making such predictions. In addition, there was an important turnover in vertical dominance in these openings. Non-commercial woody competitors were frequently dominant in early years but were often replaced by commercial hardwoods, notably yellow birch. We propose certain thresholds for assessing the success of post-harvest regeneration and for evaluating the need for a cleaning treatment.

Survival and Growth Potential of Aeromonas hydrophila in Reconditioned Pork-Processing-Plant Water†

1996 ◽  
Vol 59 (8) ◽  
pp. 881-885 ◽  
Author(s):  
SAMUEL A. PALUMBO ◽  
JEFFREY CALL ◽  
BINH HUYNH ◽  
JOSEPH FANELLI
Keyword(s):  
Aeromonas Hydrophila ◽  
Growth Potential ◽  
Residual Chlorine ◽  
Processing Plant ◽  
Plant Water ◽  
Survival Times ◽  
Term Survival ◽  
Growth And Survival ◽  
Survival And Growth

The growth and survival of Aeromonas hydrophila K144 was studied in reconditioned pork-processing-plant water. Neutralization of residual chlorine by thiosulfate permitted growth and long-term survival of the bacterium at temperatures ranging from 5 to 28°C; growth was also observed at 37 and 42°C but survival times were shorter. The coliform growth response, a bioassay system to measure the amount of nutrients available for microbial growth, for the reconditioned water was 2.91 ± 0.61, which agreed with our observation that this water contained sufficient nutrients to support about 3 log units of growth of A. hydrophila. Our results indicate that residual chlorine levels are necessary to prevent the growth of any A. hydrophila which might contaminate reconditioned water.

The effect of container size on overwintering survival and growth of herbaceous perennials

2006 ◽  
Vol 86 (3) ◽  
pp. 817-820 ◽  
Author(s):  
E. Svendsen ◽  
K. K. Tanino
Keyword(s):  
Low Temperature ◽  
Plant Growth ◽  
Key Words ◽  
Growth Potential ◽  
Growth And Survival ◽  
Perennial Plants ◽  
Herbaceous Perennials ◽  
Survival And Growth ◽  
Overwintering Survival ◽  
Almost All

The effect of container size on the growth and survival of herbaceous perennials (Artemesia, Lamium, Thymus, Echinacea Monarda, Gentiana, Penstemon, Stachys) overwintered over two seasons at two commercial nurseries was evaluated. Results indicate: (1) For most species, container size does not affect survival; (2) Container size was a significant factor in plant growth and in almost all cases, a larger container resulted in a larger plant compared with a smaller container. Plug-grown perennials may be fall planted in their final container size to maximize growth potential by the following spring. Key words: Low temperature, overwintering, storage, perennial plants

scholarly journals Root Growth Potential and Microsite Effects on Conifer Seedling Establishment in Northern Idaho

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 597
Author(s):  
Jacob A. Reely ◽  
Andrew S. Nelson
Keyword(s):  
Root Growth ◽  
Douglas Fir ◽  
Seedling Quality ◽  
Growth Potential ◽  
Larix Occidentalis ◽  
Root Growth Potential ◽  
Western Larch ◽  
Neighborhood Conditions ◽  
Seedling Performance ◽  
Survival And Growth

Environmental conditions and seedling quality interact to produce complex patterns of seedling survival and growth. Root growth potential (RGP) is one metric of seedling quality that can be rapidly measured prior to planting, but the correlation of RGP and seedling performance is not consistent across studies. Site factors including microsite objects that cast shade and competing vegetation can also influence seedling performance. We examined the effects of RGP, presence/absence of a microsite object, and competition cover on the survival and growth of three native conifers to the Inland Northwest, USA, over 5 years. We found that RGP had no effect on the survival or growth of western larch (Larix occidentalis), Douglas fir (Pseudotsuga menziesii var. glauca), and grand fir (Abies grandis) at a mesic north aspect site and a xeric south aspect site. Comparatively, the presence of a microsite increased the odds of survival by 37% for western larch and 158% for grand fir, while the absence of forb cover increased the odds of survival of western larch by 72% and of grand fir by 26%. Douglas fir was less sensitive to microsites and competition. The strong effects of neighborhood conditions around seedlings help inform silvicultural practices to enhance the establishment of western larch and grand fir, including planting seedlings near shading objects and competition control, while these practices may not be as important for Douglas fir.

Rare forest types in northeastern Ontario: a classification and analysis of representation in protected areas

2010 ◽  
Vol 40 (3) ◽  
pp. 423-435 ◽  
Author(s):  
Charles R. Drever ◽  
James Snider ◽  
Mark C. Drever
Keyword(s):  
Protected Areas ◽  
Local Population ◽  
Red Oak ◽  
Betula Alleghaniensis ◽  
White Pine ◽  
Yellow Birch ◽  
Eastern White Pine ◽  
Habitat Specificity ◽  
White Cedar ◽  
Eastern White Cedar

Our objective was to assess the relative rarity and representation within protected areas of Standard Forest Units (SFUs) in northeastern Ontario by applying the concepts of geographic range, habitat specificity, and local population size. SFUs are stand type classifications, routinely employed by forest managers, based on tree composition, disturbance history, and prescribed silvicultural system. We identified several SFUs as rare because of a narrow distribution, association with only one landform type, or lack of at least one stand larger than an ecoregion-specific threshold. In the Boreal forest, rare SFUs comprised stands dominated by eastern hemlock ( Tsuga canadensis (L.) Carrière), red oak ( Quercus rubra L.), yellow birch ( Betula alleghaniensis Britt.), or eastern white-cedar ( Thuja occidentalis L.). Rare SFUs also included eastern white pine ( Pinus strobus L.) and (or) red pine ( Pinus resinosa Ait.) leading stands managed by shelterwood or seed tree silviculture as well as low-lying deciduous stands and selection-managed stands of shade-tolerant species. In the Great Lakes – St. Lawrence forest, rare SFUs were yellow birch stands, stands dominated by conifer species abundant in the Boreal, and shelterwood-managed hardwood stands. Several rare SFUs had <12% of their total area in protection, i.e., stands dominated by eastern white pine, yellow birch, eastern white pine – red oak, or eastern white-cedar. These rare stand types require increased protection in reserves and tailored silvicultural practices to maintain their probability of persistence.

scholarly journals Tolerant hardwood natural regeneration 15 years after various silvicultural treatments on an industrial freehold of northwestern New Brunswick

2013 ◽  
Vol 89 (04) ◽  
pp. 512-524 ◽  
Author(s):  
Martin Béland ◽  
Bruno Chicoine
Keyword(s):  
New Brunswick ◽  
Natural Regeneration ◽  
Sugar Maple ◽  
Mineral Soil ◽  
Soil Disturbance ◽  
Betula Alleghaniensis ◽  
Yellow Birch ◽  
American Beech ◽  
Partial Cutting ◽  
Selection Cutting

We examined applicability of various partial cutting systems in order to regenerate tolerant hardwood stands dominated by sugar maple (Acer saccarhum), American beech (Fagus grandifolia) and yellow birch (Betula alleghaniensis) on northern New Brunswick J.D. Irving Ltd. freehold land. Sampling of 1065 one-m2 plots in 31 stands managed by selection cutting, shelterwood method and strip or patch cutting and in six control stands allowed a 15-year retrospective study of natural regeneration in stands of low residual densities and with minimal soil disturbance and no control of competing vegetation. Beech regeneration was most abundant in the patch cuts, yellow birch in shelterwood stands and sugar maple in the selection system areas. Results suggest that initial stand conditions influence the composition of the regeneration more than the prescribed treatment. At the stand scale (a few hectares), sugar maple recruitment was positively influenced by its proportion in the initial stand, and negatively by the cover of herbs and shrubs. Yellow birch regeneration was mainly affected by shrub competition. At the plot (1 m2) scale, mineral soil and decayed wood substrates and ground-level transmitted light were determinant factors for yellow birch regeneration. Beech-dominated stands were likely to regenerate to beech. A dense beech sucker understory was promoted in harvested patches. Areas with dense understory of American beech, shrubs, or herbs require site preparation to reduce interference either before or at the time of partial cutting. Shelterwood seed cutting and selection cutting should leave a residual of 12 m2/ha and 17 m2/ha respectively in seed trees uniformly distributed.

scholarly journals Preliminary results of intraspecific sterlet hybrid (Siberian sterlet × sterlet) rearing under intensive conditions

2012 ◽  
pp. 17-19
Author(s):  
Tibor Feledi ◽  
Svetlana Lengyel ◽  
András Rónyai
Keyword(s):  
Water Temperature ◽  
Growth Potential ◽  
Optimal Range ◽  
Applied Water ◽  
Early Maturation ◽  
Preliminary Results ◽  
Temperature Range ◽  
Survival And Growth ◽  
Size Heterogeneity ◽  
Intraspecific Hybrid

Due to early maturation and a small size, sterlet (Acipenserrut-henus) is a very advantageous fish for intensive sturgeon farming with regard to caviar production. According to our previous observations, the growth potential of Siberian sterlet (A.ruthenusmarsiglii) is higher than that of the European one. In our experiment, sterlet and an intraspecific hybrid (Siberian sterlet × sterlet) were tested under intensive tank conditions. During the 8 weeks of the experiment, survival, growth and size heterogeneity were investigated. According to the results, there were no significant differences in survival and growth but the size heterogeneity was higher in the hybrid. It is supposed that, in our trial, the applied water  temperature range (24.0–25.5 °C) was optimal for sterlet, but was probably above the optimal range for the hybrid.

scholarly journals Production of radioisotopes within a plasma focus device

2005 ◽  
Vol 20 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Ergisto Angeli ◽  
Agostino Tartari ◽  
Michele Frignani ◽  
Vincenzo Molinari ◽  
Domiziano Mostacci ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Plasma Focus ◽  
Reaction Rates ◽  
Experimental Production ◽  
Endogenous Production ◽  
The Us ◽  
Further Development ◽  
Radio Isotopes ◽  
Very High

In recent years, research conducted in the US and in Italy has demonstrated production of radioisotopes in plasma focus devices, and particularly, on what could be termed "endogenous" production, to wit, production within the plasma it self, as opposed to irradiation of tar gets. This technique relies on the formation of localized small plasma zones characterized by very high densities and fairly high temperatures. The conditions prevailing in these zones lead to high nuclear reaction rates, as pointed out in previous work by several authors. Further investigation of the cross sections involved has proven necessary to model the phenomena involved. In this paper, the present status of research in this field is re viewed, both with regards to cross section models and to experimental production of radio isotopes. Possible out comes and further development are discussed.

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