Glyphosate efficacy on eastern Canadian forest weeds. Part II: deposit–response relationships and crop tolerance

1992 ◽  
Vol 22 (8) ◽  
pp. 1160-1171 ◽  
Author(s):  
D. G. Pitt ◽  
R. A. Fleming ◽  
D. G. Thompson ◽  
E. G. Kettela
Keyword(s):  
Black Spruce ◽  
Weather Conditions ◽  
Post Treatment ◽  
Red Maple ◽  
White Birch ◽  
Crown Area ◽  
Crop Tolerance ◽  
Area Reduction ◽  
Application Systems ◽  
Four Blocks

First-season herbicide efficacy and crop tolerance results are presented for a range of glyphosate (VISION®) rates (0–1.00 kg acid equivalent per hectare) aerially applied with two different dispersal systems (AU5000 Micronairs® and conventional hydraulic nozzles). Derivative-free nonlinear regression was used to model post-treatment raspberry cover (Rubusidaeus L. var. strigosus (Michx.) Maxim.) as an exponentially decreasing function of chemical deposit (R2 = 0.87). Similar methods were used to model post-treatment crown area as a function of chemical deposit and pretreatment crown area for pin cherry (Prunuspensylvanica L.f.) (R2 = 0.92), red maple (Acerrubrum L.) (R2 = 0.79), white birch (Betulapapyrifera Marsh.) (R2 = 0.93), elderberry (Sambucuspubens Michx.) (R2 = 0.85), and aspen (Populustremuloides Michx.) (R2 = 0.96). Acceptable first-season control (>60% cover reduction) of raspberry, pin cherry, elderberry, and aspen was achieved with rates of deposit ≥0.50 kg acid equivalent per hectare. Red maple and white birch crown area reduction averaged 60% at the highest rate tested (1 kg acid equivalent per hectare). Significant differences in efficacy attributable to the different dispersal systems were found only for pin cherry: the Micronair system resulted in 30% greater efficacy on one of the four blocks tested (P < 0.0001). On this particular block, characterized by unstable weather conditions during treatment, both systems produced significantly greater efficacy than observed on the other blocks for all species studied except aspen (P < 0.01). No significant differences were detected in black spruce (Piceamariana (Mill.) B.S.P.) health patterns in areas treated with the two different application systems (P = 0.780). Crop trees in untreated areas declined in health relative to trees in treated areas (P < 0.001).

Sap yields, sugar content, and soluble carbohydrates of saps and syrups of some Canadian birch and maple species

1987 ◽  
Vol 17 (3) ◽  
pp. 263-266 ◽  
Author(s):  
A. R. C. Jones ◽  
I. Alli
Keyword(s):  
Sap Flow ◽  
Sugar Maple ◽  
Sugar Content ◽  
Soluble Carbohydrates ◽  
Red Maple ◽  
White Birch ◽  
Yellow Birch ◽  
Total Carbohydrate ◽  
Total Carbohydrate Content ◽  
Maple Sap

During the spring of 1984 and 1985, white birch (Betulapapyrifera Marsh), sweet birch (B. lenta L), and yellow birch (B. alleghaniensis Britt.) were tapped to determine sap yields and syrup characteristics. These properties were compared with sap yields and syrup produced from sugar maple (Acersaccharum Marsh) and red maple (A. rubrum L). The sap flow seasons were as follows: white birch, 23 days (April 7–29, 1984) and 29 days (April 5 – May 3, 1985); sweet birch, 26 days (1984); yellow birch, 25 days (1985). The sap flow season for the maple species was much earlier than the birch species. Maple sap flow seasons were as follows: sugar maple, 16 days (March 28 – April 12, 1984) and 45 days (March 10 – April 23, 1985); red maple, 44 days (March 11 – April 23, 1985). Sap yields were as follows: white birch, 80.5 L in 1984 (1.0% sap) 51.0 L in 1985 (1.0% sap); sweet birch, 48.0 L in 1984 (0.5% sap); yellow birch, 28.4 L in 1985 (0.5% sap); red maple, 30.6 L in 1985 (2.3% sap); sugar maple, 53.5 L in 1985 (4.5% sap). Sap analyses showed the average total carbohydrate content of all birch saps and all maple saps was 9.2 and 24.5 g/L, respectively. The average sugar contents of the syrups from the birch saps and the maple saps were 302 and 711 g/L, respectively. The average pH of birch and maple saps were similar but the average pH of the syrups obtained from the birch saps was substantially lower than that of the syrups obtained from the maple saps.

Portrait préindustriel dans un contexte de grande variabilité naturelle: une étude de cas dans le centre du Québec (Canada)

2011 ◽  
Vol 87 (05) ◽  
pp. 612-624 ◽  
Author(s):  
Eric Alvarez ◽  
Louis Bélanger ◽  
Louis Archambault ◽  
Frédéric Raulier
Keyword(s):  
Temperate Forest ◽  
Forest Cover ◽  
Sustainable Forest Management ◽  
Forest Succession ◽  
Black Spruce ◽  
Spatial Scales ◽  
White Birch ◽  
Industrial Landscape ◽  
Industrial Forest ◽  
Landscape Scales

Pre-industrial forest cover portrait is a recognized method for establishing the bases of sustainable forest management. However, it is a spatially and temporally dependant concept that should be used with caution in presence of big fires. The objective of the study was to portray the pre-industrial landscape in a mixedwood temperate forest in central Quebec at different spatial scales. The study was based on archival records from a forest company. The pre-industrial forest cover landscape of our study area was mainly composed of mature or old-growth (>100 years) stands and dominated by mixedwood forest stands with intolerant hardwoods. The main tree species were white birch, black spruce and jack pine, three species associated to forest succession after fire in the boreal forest. Considering the great variability caused by the fires and partial knowledge of this variability, for each spatial scale considered, we propose some management targets based on the main pre-industrial characteristics of this forest. To respect the pre-industrial variability, our study suggested that silviculture should be adapted at different landscape scales. Cover types and age class targets should be based on main preindustrial characteristics at each landscape scale analyzed.

Autumn poisoning hazards

UK-Vet Equine ◽  
2019 ◽  
Vol 3 (5) ◽  
pp. 182-190 ◽  
Author(s):  
Nicola Bates
Keyword(s):  
Clinical Signs ◽  
Weather Conditions ◽  
Mushroom Poisoning ◽  
Horse Chestnut ◽  
Cyanogenic Glycosides ◽  
Red Maple ◽  
Prunus Species ◽  
Potential Risks ◽  
Summer Growth ◽  
Autumn Crocus

The main poisoning hazard of autumn is the abundance of fruits and seeds following summer growth, but if the summer has seen extreme weather conditions, then pasture may be poor and horses may eat plants they would normally avoid. Usually the most significant hazard for horses in the autumn is atypical myopathy from repeated ingestion of sycamore seeds. Dried or wilted leaves of a related species, red maple, can cause haemolysis and methaemoglobinaemia in equines. Other potential risks in the autumn include yew; autumn crocus; oak (acorns); horse chestnut (conkers); plants containing cyanogenic glycosides, such as Prunus species; and ragwort. The fruit bodies of fungi (that is, mushrooms) are also abundant in warm, wet weather and although rarely reported (and possibly underreported), mushroom poisoning is a potential risk in horses. Depending on the type of mushroom there is risk of gastrointestinal, neurological, renal and liver effects. Treatment of plant and mushroom poisoning in horses will depend on the clinical signs and the plant or mushroom involved, but should include identification and removal of the plant or mushroom, and symptomatic care.

Classifying forestland from model-generated tree species habitat suitability in the Western Ecoregion of Nova Scotia, Canada

2013 ◽  
Vol 43 (6) ◽  
pp. 517-527 ◽  
Author(s):  
Mark Baah-Acheamfour ◽  
Charles P.-A. Bourque ◽  
Fan-Rui Meng ◽  
D. Edwin Swift
Keyword(s):  
Nova Scotia ◽  
Tree Species ◽  
Habitat Suitability ◽  
Sugar Maple ◽  
Forest Succession ◽  
Red Maple ◽  
White Birch ◽  
Permanent Sample Plots ◽  
Natural Range ◽  
Hybrid Classification

Forestland classification is central to the sustainable management of forests. In this paper, we explore the possibility of classifying forestland from species–habitat–suitability indices and a hybrid classification of modeled data. Raster-based calculations of species–habitat–suitability were derived as a function of landscape-level descriptions of incident photosynthetically active radiation (PAR), soil water content (SWC), and growing degree-days (GDD) for southwestern Nova Scotia, Canada. PAR and SWC were both generated with the LanDSET model and GDD from thermal data captured with the space-borne MODIS sensor. We compared the distribution of predicted forestland types with the natural range of target species as found in the provincial permanent sample plots (PSPs). Reasonable agreement (≥50% accuracy) existed between some forestland types (e.g., red maple – white birch – red oak and balsam fir – red maple) and PSP-based assessments of species presence–absence. Agreement was noticeably lower for other forestland types, such as sugar maple – beech – yellow birch (<50% accuracy). This discrepancy is attributed to forest-forming factors not directly addressed by the model, e.g., forest succession, stand interventions, and disturbance. Their addition in the model could change the dynamics of tree-species preference in southwest Nova Scotia and is worth examining. True model inaccuracies accounted for about 0.3%–15.0% of the total reported error.

Spatial pattern analyses of post-fire residual stands in the black spruce boreal forest of western Quebec

2010 ◽  
Vol 19 (8) ◽  
pp. 1110 ◽  
Author(s):  
Amar Madoui ◽  
Alain Leduc ◽  
Sylvie Gauthier ◽  
Yves Bergeron
Keyword(s):  
Black Spruce ◽  
Weather Conditions ◽  
Spatial Analyses ◽  
Fire Size ◽  
The West ◽  
Forest Patches ◽  
Burned Areas ◽  
Large Fires ◽  
The Many ◽  
Landsat Satellite

In this study, we characterised the composition and configuration of post-fire residual habitats belonging to two physiographic zones of the black spruce–moss domain in western Quebec. Thirty-three large fires (2000–52 000 ha) were selected and extracted on classified Landsat satellite imagery. The results show that a minimum of 2% and a maximum of 22% of burned areas escaped fire, with an overall average of 10.4%. The many forest patches that partially or entirely escaped fire formed residual habitats (RHs). It was found that although the area of RHs follows a linear relationship with fire size, their proportion appears relatively constant. Spatial analyses showed that the fires could be separated into two groups depending on the physiographic zones (East-Canadian Shield v. West-Clay Belt Lowlands). Fires in the west zone generate less RHs and appear to be associated with more extreme weather conditions. In most cases there was no association with water or wetlands; in some fires the presence of RHs is associated with the proximity of water bodies. The failure to find an association between RHs and wetlands suggests that this type of environment is part of the fuel. Coniferous woodland with moss appears particularly overrepresented within RHs. Our results suggest that the local and regional physiographic conditions strongly influence the creation of RHs; therefore, it is important to consider those differences when applying ecosystem-based management.

Geography and Bathymetry of Selected Lake Basins, Experimental Lakes Area, Northwestern Ontario

1971 ◽  
Vol 28 (2) ◽  
pp. 139-155 ◽  
Author(s):  
G. J. Brunskill ◽  
D. W. Schindler
Keyword(s):  
Black Spruce ◽  
Soil Depth ◽  
White Birch ◽  
Lake Agassiz ◽  
Preliminary Calculation ◽  
Experimental Lakes Area ◽  
Glacial Ice ◽  
Winnipeg River ◽  
Sand And Gravel ◽  
Lake Basins

The Experimental Lakes Area (ELA) is located at 93°30′–94°00′W and 49°30′–49°45′N at an altitude of 360–380 m above mean sea level. This area is underlain by Precambrian acid granites overlain in some areas by thin glacial drift composed largely of sand and gravel of quartz, plagioclase, and K-feldspar. The area was under glacial ice about 14,000 years B.P. (before present). With the melting of this glacial ice, ELA was situated on the eastern margin of glacial Lake Agassiz. As Lake Agassiz levels receded, the present lake basins were formed. The ELA watersheds now drain into the Winnipeg River, which is in the Hudson Bay drainage system.Mean annual temperatures in the vicinity of ELA are between 0.5 and 2.2 C, and annual precipitation is between 500 and 750 mm. Brunisols were observed over sand deposits in the ELA, but considerable variation in soil types and soil depth were also found. ELA is in a boreal (fire-controlled) subclimax forest of jack pine, black spruce, trembling aspen, and white birch. Aquatic macrophytes were scarce in the littoral zone of ELA lakes. Nearby logging operations and hunting and sport fishing have not influenced the immediate watersheds of ELA lakes.Morphometric maps and measurements are given for 16 lakes in ELA. These lakes vary from 2.5 to 33 m in maximum depth, and from 1.7 to 56 ha in lake surface area. Using estimates of precipitation, evaporation, evapotranspiration, drainage areas, and lake morphometry, a preliminary calculation of theoretical water renewal time is given for these lakes. These values range from 2.6 to 38 years.

Abundance and activity of N2-fixing bacteria in decaying wood

1991 ◽  
Vol 21 (9) ◽  
pp. 1299-1304 ◽  
Author(s):  
O. Q. Hendrickson
Keyword(s):  
Nitrogenase Activity ◽  
Carbon Sources ◽  
Betula Papyrifera ◽  
Birch Wood ◽  
Red Maple ◽  
Aspen Wood ◽  
White Birch ◽  
White Pine ◽  
Aerobic Conditions ◽  
Decaying Wood

Populations of N2-fixing bacteria exceeded 106/g in moderately decayed trembling aspen (Populustremuloides Michx.) and white birch (Betula papyrifera Marsh.) logs. Lower numbers were found in red maple (Acerrubrum L.) and conifer logs (Abiesbalsamea (L.) Mill., Pinusbanksiana Lamb.) at similar decay states. Populations were assayed using a combined-carbon medium in semisolid agar under aerobic conditions. Single carbon sources generally yielded lower and more variable numbers. With water and carbon supplements, aspen and birch wood showed high potential nitrogenase activity (>400 nmol C2H4•g−1•day−1) at 30 °C under aerobic conditions, and even greater activity (>1000 nmol C2H4•g−1•day−1) during a 3-day incubation under waterlogged conditions. In the absence of supplemental carbon, aspen wood remained active but birch wood did not. Wood from other species supported much lower nitrogenase activity under aerobic conditions, and waterlogging was strongly inhibitory. A highly decayed white pine (Pinusstrobus L.) log had low populations (<104/g) of N2-fixing bacteria and did not reduce C2H2 under any treatments. Results support the hypothesis that a relationship exists between (i) populations and activity of N2-fixing bacteria and (ii) the decay susceptibility of wood of different species.

Weight loss and nutrient changes in decomposing litter and forest floor material in New Brunswick forest stands

1978 ◽  
Vol 56 (21) ◽  
pp. 2730-2749 ◽  
Author(s):  
David A. MacLean ◽  
Ross W. Wein
Keyword(s):  
Weight Loss ◽  
Forest Floor ◽  
Red Maple ◽  
White Birch ◽  
Deciduous Species ◽  
Forest Sites ◽  
Pine Stands ◽  
Study Sites ◽  
Nutrient Changes ◽  
Floor Material

Weight loss and nutrient (N, P, K, Ca, Mg) changes with decomposition were examined over a 2-year period fora variety of kinds of litter on five forest sites. Litter types included pine needles, leaves of four deciduous species (red maple, pin cherry, trembling aspen, and white birch), branches of pine and four deciduous species, understory vegetation, and partially decomposed forest floor material, while the study sites consisted of jack pine stands aged 16, 29, and 57 years and mixed hardwood stands aged 7 and 29 years. Statistically significant differences in rate of weight loss were found to occur, with understory and leaf litter significantly faster on the hardwood stands than on the pine stands, understory litter faster on the 7-year-old hardwood stand than on the 29-year-old stand, and forest floor material faster on the 29-year-old pine stand than on the 57-year-old pine stand. Among the four deciduous species examined, significant differences in leaf weight loss also occurred, but differences among branch litter were nonsignificant. The mass of N in samples generally decreased with decomposition, with increases occurring in a few cases (i.e., pine understory and needle litter). Phosphorus mass generally increased on the pine sites and decreased on the hardwood sites; this appeared to be largely a function of the low initial P concentrations of litter on the pine sites. In general, the mass of K, Ca, and Mg decreased in the various samples with decomposition; the loss of K from deciduous leaves in this study was particularly fast and was greater than other values from the literature.

FOLIAR AND SYSTEMIC APPLICATIONS OF NEEM SEED EXTRACT FOR CONTROL OF SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA: TORTRICIDAE), INFESTING BLACK AND WHITE SPRUCE SEED ORCHARDS

1997 ◽  
Vol 129 (4) ◽  
pp. 645-655 ◽  
Author(s):  
Kevin W. Wanner ◽  
Blair V. Helson ◽  
Barry C. Kostyk
Keyword(s):  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Larval Mortality ◽  
Spruce Budworm ◽  
Weather Conditions ◽  
Urban Environments ◽  
Seed Extract ◽  
Neem Seed ◽  
Adverse Weather ◽  
Neem Seed Extract

AbstractNeem seed extract (20, 60, and 180 ppm azadirachtin) applied to the crowns of black spruce trees immediately prior to female reproductive bud flush, resulted in high mortality of early instar spruce budworm larvae. Dose-dependent reductions of 40–93%, as compared with check trees, were observed 2 and 4.5 weeks after treatment. Seed cone protection from grazing damage, however, was moderate; at 60 ppm azadirachtin, the incidence of cone grazing was reduced 29%, and the proportion of severely grazed cones reduced 39%, as compared with check trees. Larval mortality and bud damage observed in the laboratory corroborated field results. High toxicity to second-instar larvae, and performance during adverse weather conditions, supports the potential of neem seed extract for control of spruce budworm defoliation. However, both laboratory and field results indicate that feeding occurs before the effects of neem seed extract manifest, resulting in moderate protection of cones. Whereas foliage can tolerate low levels of feeding, female strobili are damaged significantly. Excellent protection of foliage was achieved from systemic injections of neem seed extract to white and black spruce trees (1.5 g azadirachtin/tree). Neem seed extract, formulated for systemic application, could provide a botanical alternative for control of forest pests in urban environments.

Empirical models of forest fire initial attack success probabilities: the effects of fuels, anthropogenic linear features, fire weather, and management

2006 ◽  
Vol 36 (12) ◽  
pp. 3155-3166 ◽  
Author(s):  
M Cecilia Arienti ◽  
Steven G Cumming ◽  
Stan Boutin
Keyword(s):  
Failure Probability ◽  
Response Times ◽  
Black Spruce ◽  
Weather Conditions ◽  
Fire Weather ◽  
Initial Attack ◽  
Linear Features ◽  
Factors Affecting ◽  
Forest Fuels ◽  
Area Burned

Canadian fire managers seek to contain fires below some target size (here 3 ha) by initial attack (IA). Suppression failures occur when fire size at IA exceeds this target (a response failure) or if an initially small fire cannot be contained below it (a containment failure). We examined the effects of cause, season, forest fuels, anthropogenic linear features, weather, and fire management (response time, size at IA) on the probability of these two types of suppression failures, using multiple logistic regression on 1196 fires that occurred within the boreal mixedwood forest of northeastern Alberta during 1995–2002. The frequencies of containment (7%) and response failures (10%) were similar, but the latter accounted for 85% of the area burned. Response failure probability was greater for fires caused by lightning than those caused by humans and increased with longer response times, local abundance of black spruce in summer, and pine fuel under severe fire weather. We found no effect of linear features or other fuel types. Containment failure probability was related to size at IA and fire weather conditions. Our models suggest that a reduction in area burned might be possible if additional fire-specific factors affecting response failure probability could be incorporated into operational decisions.

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