Autecology of Erythronium grandiflorum in western Canada

2001 ◽  
Vol 79 (4) ◽  
pp. 500-509 ◽  
Author(s):  
Dawn C Loewen ◽  
Geraldine A Allen ◽  
Joseph A Antos
Keyword(s):  
Canopy Cover ◽  
Detrended Correspondence Analysis ◽  
Coniferous Forests ◽  
Deciduous Trees ◽  
Growth Stages ◽  
Western Canada ◽  
Percent Cover ◽  
Subalpine Meadows ◽  
Associated Species ◽  
Erythronium Grandiflorum

Habitat requirements of the yellow glacier lily, Erythronium grandiflorum Pursh, were studied at 38 sites in southern British Columbia and southwestern Alberta. At each site we recorded densities of E. grandiflorum growth stages from seedling to flowering, environmental characteristics of the site, and percent cover of associated plant species. We carried out detrended correspondence analysis (DCA) of the sites based on cover of associated species, and examined rank correlations between site environmental variables and site ordination scores. Variation among sites was related primarily to elevation and the presence of deciduous vs. coniferous trees. All growth stages of E. grandiflorum were less abundant in coniferous forests than in open areas or sites with deciduous trees, suggesting that evergreen canopies restrict the species on many sites where it could otherwise grow. Although E. grandiflorum populations were most commonly found in subalpine meadows, they flowered more abundantly in low-elevation populations. Recruitment was frequent, with seedlings occurring at many sites; we also showed that detached bulb segments can give rise to new ramets. The present widespread distribution of E. grandiflorum may derive from a post-glacial period with extensive meadow habitat that was favourable for rapid spread.Key words: canopy cover, elevation, yellow glacier lily, post-glacial migration, subalpine meadows.

scholarly journals Individual and Combined Effects of Planting Date, Seeding Rate, Relative Maturity, and Row Spacing on Soybean Yield

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 605
Author(s):  
Peder K. Schmitz ◽  
Hans J. Kandel
Keyword(s):  
Seed Yield ◽  
Management Practices ◽  
Synergistic Effects ◽  
Canopy Cover ◽  
Planting Date ◽  
Row Spacing ◽  
Growth Stages ◽  
Seeding Rate ◽  
Yield Increase ◽  
Beginning Of Flowering

Planting date (PD), seeding rate (SR), relative maturity (RM) of cultivars, and row spacing (RS) are primary management factors affecting soybean (Glycine max (L.) Merr.) yield. The individual and synergistic effects of PD, SR, RM, and RS on seed yield and agronomic characteristics in North Dakota were herein investigated. Early and late PD, early and late RM cultivars, two SR (408,000 and 457,000 seed ha−1), and two RS (30.5 and 61 cm) were evaluated in four total environments in 2019 and 2020. Maximizing green canopy cover prior to the beginning of flowering improved seed yield. Individual factors of early PD and narrow RS resulted in yield increase of 311 and 266 kg ha−1, respectively. The combined factors of early PD, late RM, high SR, and narrow RS improved yield by 26% and provided a $350 ha−1 partial profit over conventional practices. Canopy cover and yield had relatively weak relationships with r2 of 0.36, 0.23, 0.14, and 0.21 at the two trifoliolate, four trifoliolate, beginning of flowering, and beginning of pod formation soybean growth stages, respectively. Producers in the most northern soybean region of the USA should combine early planting, optimum RM cultivars, 457,000 seed ha−1 SR, and 31 cm RS to improve yield and profit compared to current management practices.

scholarly journals Approach for Image-Based Semantic Segmentation of Canopy Cover in Pea–Oat Intercropping

Agriculture ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 354
Author(s):  
Sebastian Munz ◽  
David Reiser
Keyword(s):  
Cropping Systems ◽  
Canopy Cover ◽  
Semantic Segmentation ◽  
Weed Suppression ◽  
Growth Stages ◽  
Light Competition ◽  
Management Options ◽  
Sole Cropping ◽  
Single Dataset ◽  
High Yields

Intercropping systems of cereals and legumes have the potential to produce high yields in a more sustainable way compared to sole cropping systems. Their agronomic optimization remains a challenging task given the numerous management options and the complexity of interactions between the crops. Efficient methods for analyzing the influence of different management options are needed. The canopy cover of each crop in the intercropping system is a good determinant for light competition, thus influencing crop growth and weed suppression. Therefore, this study evaluated the feasibility to estimate canopy cover within an intercropping system of pea and oat based on semantic segmentation using a convolutional neural network. The network was trained with images from three datasets during early growth stages comprising canopy covers between 4% and 52%. Only images of sole crops were used for training and then applied to images of the intercropping system. The results showed that the networks trained on a single growth stage performed best for their corresponding dataset. Combining the data from all three growth stages increased the robustness of the overall detection, but decreased the accuracy of some of the single dataset result. The accuracy of the estimated canopy cover of intercropped species was similar to sole crops and satisfying to analyze light competition. Further research is needed to address different growth stages of plants to decrease the effort for retraining the networks.

scholarly journals The economic benefits of reductions in nitrogen loads from stormwater runoff by street trees

2020 ◽  
Author(s):  
Mariana D. Baptista ◽  
Marco Amati ◽  
Tim D. Fletcher ◽  
Matthew J. Burns
Keyword(s):  
Stormwater Runoff ◽  
Canopy Cover ◽  
Annual Runoff ◽  
Urban Trees ◽  
Deciduous Trees ◽  
Street Trees ◽  
Runoff Volume ◽  
Nitrogen Loads ◽  
Tree Canopy Cover ◽  
The Impact

Abstract It is increasingly recognised that urban trees can contribute to reducing stormwater runoff by intercepting and retaining a fraction of rainfall received. What is less studied is the translation of this to reduced pollutant loads being transferred to receiving streams, rivers, and water bodies. In this paper, we assess interception of two tree species (Eucalyptus microcorys and Ulmus procera) in an urban park. This data is used in simple water balance modelling to predict the environmental and economic benefit of reducing nitrogen loads to receiving waterways as a function of reduced runoff volume resulting from rainfall interception by urban trees on public land (21% of the catchment area). We use a highly urbanized catchment in Melbourne, Australia to demonstrate the impact of an urban forest dominated by deciduous trees, evergreen trees or a mixed tree canopy cover. We found that doubling the urban canopy cover in the catchment, while keeping the current mix ratio of deciduous and evergreen trees, could reduce annual runoff volume by 30 mm (92 MLyr−1). Using the prescribed values that developers must pay the local water authority for nitrogen treatment as a condition of new development, we calculate that this would deliver a nitrogen load removal benefit of AUD$ 200/tree. If only deciduous trees are planted the annual runoff reduction would decrease to 24 mm (73 MLyr−1) and increases to 37 mm (112 MLyr−1) if only evergreen trees are planted. This study highlights both the additional benefits of public street trees and the differences in deciduous and evergreen trees which should be accounted for by policy makers.

The upland hardwood component of Prince Edward Island's remnant Acadian forest: determination of depth of edge and patterns of exotic plant invasion

2003 ◽  
Vol 81 (11) ◽  
pp. 1113-1128 ◽  
Author(s):  
Kate MacQuarrie ◽  
Christian Lacroix
Keyword(s):  
Exotic Species ◽  
Plant Community ◽  
Plant Invasion ◽  
Vascular Plants ◽  
Canopy Cover ◽  
Percent Cover ◽  
Exotic Plant ◽  
Exotic Plant Invasion ◽  
Acadian Forest ◽  
Study Sites

The upland hardwood component of Prince Edward Island's Acadian forest is among the best remaining examples of the precolonial landscape, but it has been severely fragmented during the past 300 years of human use and settlement. Despite the ecological importance of this remnant habitat and its level of fragmentation, there has been no assessment of depth of edge or exotic plant invasion in these areas. Three 300 m long edge–interior transects were established in each of six study sites. Nine 100-m2 circular plots were sampled along each transect at distances from 5.7 to 300 m; one external plot was established at each transect to sample species in adjacent habitats. In each plot, all vascular plants were identified, a visual estimate of percent cover was made, and soil temperature, canopy cover, and tree diameters were measured. An edge–interior plant community gradient was found within these forests; a plant community characteristic of interior conditions was not reached until a distance of more than 120 m from an edge. This suggests that upland hardwood protected areas smaller than 240 m on a side (5.75 ha) are unlikely to include interior habitat, and sites should be greater than 320 m on all sides (10.24 ha) to ensure at least some interior habitat for vascular plants. Invasion by exotic species was found to be more extensive than that reported from other jurisdictions, and innermost (300 m) plots were not free from exotics. Fifteen exotic species were found within the study sites, with Veronica officinalis (common speedwell) and Hieracium lachenalii (hawkweed) being the most invasive, both in terms of distance penetrated and area covered.Key words: Acadian forest, fragmentation, depth of edge, protected area, Veronica, Hieracium.

Effects of conifer release with glyphosate on summer forage abundance for deer in Maine

1998 ◽  
Vol 28 (10) ◽  
pp. 1574-1578 ◽  
Author(s):  
J K Vreeland ◽  
F A Servello ◽  
B Griffith
Keyword(s):  
Deciduous Trees ◽  
Percent Cover ◽  
Large Herbivores ◽  
Positive Effects ◽  
Habitat Value ◽  
Treatment Interaction ◽  
Deciduous Shrubs ◽  
Northern Forests ◽  
The Difference ◽  
Trees And Shrubs

Effects of conifer release with glyphosate on summer forage availability for large herbivores in northern forests have received relatively little study. We determined effects of glyphosate treatment of clearcuts on abundance of summer foods for white-tailed deer (Odocoileus virginianus) at 1 and 7-10 years posttreatment. We measured the abundance (percent cover in a 0- to 1.8-m height stratum) of five forage classes for deer (leaves of deciduous trees, leaves of deciduous shrubs, forbs, grasses, ferns) on 12 clearcuts (six treated, six untreated) to determine 1-year effects and on 10 clearcuts (five treated, five untreated) to determine 7- to 10-year effects. Abundance of leaves of deciduous trees was greater on untreated sites (38 versus 11%) at 1 year posttreatment, but the difference was less (18 versus 12%) at 7-10 years posttreatment (age × treatment interaction, P = 0.005). Leaves of deciduous shrubs exhibited a similar pattern. Abundance of forbs was similar (13-14%) at 1 year posttreatment but greater on treated sites (29 versus 15%) at 7-10 years posttreatment (P = 0.03). Grasses and ferns were less abundant than other forage classes. Overall, glyphosate application initially decreased the abundance of leaves of deciduous trees and shrubs used as food in summer, but the longer term positive effects on forb abundance may result in little net change in overall habitat value.

Frequency and diversity of ectomycorrhizal and saprophytic macrofungi in the Laurentide Mountains of Quebec

1989 ◽  
Vol 67 (9) ◽  
pp. 2616-2629 ◽  
Author(s):  
Normand Villeneuve ◽  
Miroslav M. Grandtner ◽  
J. André Fortin
Keyword(s):  
Species Richness ◽  
Vascular Plants ◽  
Deciduous Forest ◽  
Black Spruce ◽  
Coniferous Forest ◽  
Diversity Indices ◽  
Organic Substrate ◽  
Coniferous Forests ◽  
Percent Cover ◽  
Saprophytic Fungi

Total macro fungus frequency in closed forest associations of the Laurentide Mountains varied little (147 – 185 %) from one to another. The macrofungal flora of the deciduous forest was composed mainly of many infrequent species, whereas coniferous forests had few, but very frequent, macrofungi. Total frequency was significantly lower (15%) in open stands of the spruce–cladina association. Species richness decreased gradually (from 125 to 34 species) towards the north and with increasing altitude. Both the Simpson and the Shannon–Wiener diversity indices were significantly lower in the coniferous forest when compared with the deciduous forest. This decrease in diversity was due to the scarcity of saprophytic fungi in mor humus, whereas the number of ectomycorrhizal species remained constant. The diversity of saprophytic fungi was related significantly to that of vascular plants, whereas the diversity of ectomycorrhizal macrofungi was related mainly to the percent cover of ectomycorrhizal hosts. A total of 195 species of macrofungi were recorded for the study sites. In the maple – yellow birch forest, most of the macrofungi were saprophytic members of the Tricholomataceae, Hygrophoraceae, Strophariaceae, and Clavariaceae, many being exclusive in this association. However, each biological group had approximately equal frequency (44–54%) and richness (37–45 taxa). Species composition of the coniferous forest differed from the former in the clear dominance of ectomycorrhizal macrofungi from the Cortinariaceae, Russulaceae, and the Boletaceae. In the black spruce – cladina association, saprophytic fungi were scarce and ectomycorrhizal species were also relatively infrequent. In all the sites, the equitability of macrofungal frequency was high, as seen by the high proportion of rare species. The decline in species richness observed in this study, when moving from deciduous to coniferous forests, corresponds well with the increase in environmental rigor and instability, as well as the decrease in the diversity of organic substrate and species of vascular plants.

Herbaceous Response to Canopy Cover, Light Intensity, and Throughfall Precipitation in Coniferous Forests

Ecology ◽  
1969 ◽  
Vol 50 (2) ◽  
pp. 255-263 ◽  
Author(s):  
R. C. Anderson ◽  
O. L. Loucks ◽  
A. M. Swain
Keyword(s):  
Light Intensity ◽  
Canopy Cover ◽  
Coniferous Forests

scholarly journals Farmer participatory research in agricultural extension programs: A case study of fertilizer management in tropical rice

2020 ◽  
Vol 56 (5) ◽  
pp. 710-721
Author(s):  
Niño P. M. C. Banayo ◽  
Yoichiro Kato
Keyword(s):  
Nutrient Management ◽  
Canopy Cover ◽  
Crop Management ◽  
Agricultural Extension ◽  
Fertilizer Application ◽  
The Philippines ◽  
Growth Stages ◽  
Fertilizer Management ◽  
Farmer Participatory Research ◽  
Rice Farmer

AbstractAgricultural extension requires close communication with farmers, and researchers must consider farmers’ perspectives on crop management. Farmers tend to take into account the canopy appearance when they decide on fertilizer application, and this is often neglected in crop management recommendations by researchers. Our objectives were to dissect the growth characteristics that farmers implicitly account for in nutrient management of tropical rice. Farmer participatory trials were conducted in irrigated and rainfed lowlands in the Philippines during the wet seasons of 2014, 2015, and 2016. Each year, 30 participating farmers made decisions on fertilizer management for plots with different seedling ages and planting densities. These treatments greatly changed the canopy appearance, and affected farmer decisions on nitrogen (N) management, particularly in the first year. We found that plant height and leaf greenness were the major determinants of their decisions in irrigated lowlands. Under rainfed conditions, the risk of drought made farmers focus on tillering rather than plant elongation and leaf color during early growth stages, and on canopy cover and plant elongation during later stages. Across years and water regimes, farmers applied 78% more N than researchers without generally increasing grain yield. Since crop diagnosis is a key for successful management by farmers, guidelines for efficient nutrient management should include numerical targets for the traits emphasized by farmers. That will help farmers better understand their crops, and the guidelines will be more user-friendly than providing only a fertilizer application prescription.

Subpixel canopy cover estimation of coniferous forests in Oregon using SWIR imaging spectrometry

2001 ◽  
Vol 106 (D6) ◽  
pp. 5151-5160 ◽  
Author(s):  
David B. Lobell ◽  
Gregory P. Asner ◽  
Beverly E. Law ◽  
Robert N. Treuhaft
Keyword(s):  
Canopy Cover ◽  
Coniferous Forests ◽  
Imaging Spectrometry

Vegetation ordination of subalpine meadows using adaptive strategies

1983 ◽  
Vol 61 (12) ◽  
pp. 3117-3127 ◽  
Author(s):  
Roger Del Moral
Keyword(s):  
Indicator Species ◽  
Environmental Gradients ◽  
Detrended Correspondence Analysis ◽  
Niche Differentiation ◽  
Habitat Types ◽  
Relative Growth ◽  
Subalpine Meadows ◽  
Morphological Index ◽  
Sedge Meadows ◽  
Vegetation Ordination

The vegetation of subalpine meadows was investigated by several multivariate analytical methods. Detrended correspondence analysis (DCA) revealed overall patterns of vegetation response to environmental gradients and identified many indicator species. Binary discriminant analysis confirmed these interpretations and identified indicator species with more clarity than did DCA. A plant strategy ordination was developed from a morphological index of competitiveness and from a relative growth rate index. Results converge to these conclusions: (i) the strategy ordination was consistent with habitat types and DCA; (ii) the degree of species niche differentiation within a community varied with productivity and disturbance; (iii) morphological and physiological niche differentiation is least in productive sedge meadows and greatest in mesic grasslands where production and disturbance are moderate. The adaptation spectra of species in a community provide useful insights about site conditions, history, and response to manipulations.

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