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  • 1
    Electronic Resource
    Electronic Resource
    Photosynthetic acclimation in eastern hemlock [Tsuga canadensis (L.) Carr.] seedlings following transfer of shade-grown seedlings to high light (1999)
    Springer
    Trees 13 (1999), S. 117-124 
    Details
    ISSN: 0931-1890
    Keywords: Key words Eastern hemlock ; Photosynthesis ; Chlorophyll fluorescence ; Light acclimation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  We studied photosynthetic acclimation of eastern hemlock [Tsuga canadensis (L.) Carr.] seedlings in the first month after sudden exposure of shade-grown seedlings to full sunlight. In a greenhouse experiment, seedlings were grown under full sun or 80% shade, and after 7 months, a sample of the shaded trees was transferred to full sun in the greenhouse. Photosynthetic responses of shaded, transferred, and sun trees were followed over the course of 26 days to track short to medium-term acclimation responses. A partial acclimation of photosynthesis at high light occurred in pre-existing (formed in the previous environment) and new foliage of transferred seedlings. This was associated with non-stomatal limitations to photosynthesis. Pre-existing foliage of transferred plants had a prolonged reduction in the ratio of variable to maximal fluorescence, and a limited capacity to adjust photochemical quenching or photosystem II quantum yield in the light to increasing light intensity compared to sun foliage, and apparently had some difficulty sustaining non-photochemical quenching. Seedling survival was only 58% among transferred seedlings, compared to 80% and 100% in the shade or sun groups, respectively. Photosystem II quantum yield in the light, and photochemical and non-photochemical quenching were similar between newly formed foliage of transferred and sun plants. These findings indicate that eastern hemlock depends strongly on the production of new foliage for photosynthetic adjustments to high light, and that development of photosynthetic competence may be a gradual process that occurs over successive foliar production cycles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009743
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  • 2
    Electronic Resource
    Electronic Resource
    Morphological indicators of stock quality and field performance of red oak (Quercus rubra L.) seedlings underplanted in a central Ontario shelterwood (1997)
    Springer
    New forests 14 (1997), S. 145-156 
    Details
    ISSN: 1573-5095
    Keywords: bareroot ; field performance ; first-order lateral roots ; growth potential ; root collar diameter ; root morphology ; stock quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The value of initial stem diameter near the root collar, shoot length and number of first-order lateral roots (FOLR) as morphological indicators of stock quality and field performance was examined for bareroot (1+0, undercut) red oak (Quercus rubra L.) underplanted in a shelterwood in central Ontario. These three attributes were measured on more than 400 seedlings prior to planting, and their relationship with height and basal diameter growth two years after planting was determined using correlation and regression analysis. Initial diameter, shoot length and number of FOLR were positively and significantly correlated with second-year height and diameter. These relationships were strongest for diameter, but this variable explained less than 25% of the total variation in growth. Of the three indicators, diameter was also the best predictor of several physical characteristics of root systems two years after planting. Initial diameter was significantly correlated with root volume, root area and lateral root, taproot and total root dry mass. Weaker relationships existed between initial shoot length and number of FOLR and second-year root system features. Stem diameter two years after planting was more strongly related to root volume, area and dry mass than was initial diameter, the probable result of adjustment in root-shoot balance of planting stock to the shelterwood environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006577201244
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  • 3
    Electronic Resource
    Electronic Resource
    Photosynthetic acclimation of shade-grown red pine (Pinus resinosa Ait.) seedlings to a high light environment (2000)
    Springer
    New forests 19 (2000), S. 1-11 
    Details
    ISSN: 1573-5095
    Keywords: chlorophyll fluorescence ; competition ; morphology ; photosynthesis ; red pine ; stomatal conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Photosynthetic light acclimation in red pine (Pinus resinosa Ait.) seedlings was examined in a greenhouse study to better understand the physiological response of this species to increased light intensity following release from competition. Seedlings grown in a high (HL), medium (ML) or low (LL) light environment for 12 weeks were transferred to high light. Gas exchange and chlorophyll fluorescence of ML and LL seedlings were measured prior to and following transfer and compared with the HL control treatment. Photosynthetic characteristics were related to initial light treatment and time after transfer. Acclimation of gas exchange features to high light in shade formed ML and LL foliage was relatively rapid, with similar values among light treatments within 57 days of transfer. Acclimation of net photosynthetic rate was similar in ML and LL seedlings, and was associated primarily with increased mesophyll conductance to CO2. The ratio of variable to maximal chlorophyll fluorescence (Fv/Fm) decreased initially after transfer, especially in LL seedlings, but recovered to normal values after 57 days. Red pine seedlings appear to be well adapted for photosynthetic acclimation to high light intensity, consistent with that reported for other early successional tree species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006668928091
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  • 4
    Electronic Resource
    Electronic Resource
    Estimating biomass of white spruce seedlings with vertical photo imagery (2000)
    Springer
    New forests 20 (2000), S. 145-162 
    Details
    ISSN: 1573-5095
    Keywords: allometry ; branch biomass ; foliar biomass ; natural regeneration ; photo imagery ; release ; silhouette area ; stem biomass ; white spruce
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Estimation of individual tree seedling biomass isrequired in a variety of forest management andresearch applications such as assessment of netprimary productivity and carbon sequestrationpotential of forest stands, understory forest fuelinventories, and development of silviculturalguidelines to promote the growth of desired treespecies. Photo imagery is a promising non-destructivemethod for estimating the aboveground biomass of treeseedlings. This method was tested using naturallyregenerated white spruce (Picea glauca (Moench)Voss) seedlings growing in the understory of a mixedconifer shelterwood in central Ontario. In the fall of1997, 45 seedlings were sampled from plots exposed toone of three mechanical release treatments (earlyspring release, mid summer release, and no release(control)) in 1994. Each seedling was photographed inthe field to measure the vertical projected area(silhouette area) of the aboveground portion of theseedling. Seedlings were harvested, basal diameter andtotal height measured, and biomass (dry mass) offoliage, branches, main stem and total abovegroundplant tissue determined. Regression analysis revealeda strong relationship between both silhouette area andbasal diameter, and seedling biomass. Coefficients ofdetermination for regression equations usingsilhouette area were equal to 0.892, 0.918, 0.926, and0.937 for the main stem, branches, foliage, and totalaboveground biomass, respectively. Respectivecoefficients of determination for regression equationsusing basal diameter were 0.960, 0.945, 0.953, and0.977. Silhouette area-based equations for totalaboveground and foliar biomass differed significantly(P 〈 0.005) among release treatments. Nosignificant differences among treatments were observedbetween silhouette area-based equations for biomass ofbranches and main stem (P 〉 0.05), or betweenbasal diameter-biomass (allometric) equations for allcomponents (P 〉 0.1). The method was thentested by validating the biomass equations using anindependent data set from 35 white spruce seedlingsfrom the same site and cohort, but exposed todifferent treatments and microenvironmentalconditions. For each seedling, biomass components werepredicted using silhouette area-based and allometricequations, and a relative error of predictioncalculated. The mean relative error for silhouettearea-based predictions varied among biomass componentsfrom −20.25% to −3.21%, with standard deviation ofthe error ranging from 23.04% to 33.44%. The meanrelative error for allometric equations ranged from−2.46% to −21.75%, with standard deviations of23.34% to 32.61%. These results suggest that: (1)photo imagery can be used as an alternative to moretraditional allometric methods of biomass estimation,and (2) general (developed for a broad range ofgrowing conditions) equations derived by either methodare preferable to those specifically calibrated for agiven growing environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006716406751
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  • 5
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    Leaf and root osmotic adjustment in drought-stressed Quercusalba, Q. macrocarpa, and Q. stellata seedlings (1988)
    Canadian Science Publishing
    Details
    Publication Date: 1988-01-01
    Description: The leaf and root tissue water relations of Quercusalba L., Quercusmacrocarpa Michx., and Quercusstellata Wang. seedlings before and after drought were examined to evaluate the occurrence and comparative extent of osmotic adjustment in seedlings of these species. Drought resulted in active osmotic adjustment in leaves of all three species, with decreases in osmotic potential at full tissue hydration and at the turgor loss point from 0.25 to 0.60 MPa. Active osmotic adjustment in Q. stellata, and increased root tissue elasticity in Q. macrocarpa and Q. alba, resulted in turgor loss of roots occurring at a water potential 0.36 to 0.66 MPa lower in drought-stressed than in well-watered seedlings. Species differed in tissue water relations only before drought, with Q. stellata exhibiting lower osmotic potentials than Q. alba and Q. macrocarpa. Estimates of the osmotic potential at full saturation were generally lower in leaves than in roots, but the osmotic potential at turgor loss was similar. Roots exhibited turgor loss at lower values of relative water content and experienced a more gradual decrease in water potential per unit water content during dehydration than did leaves. This response indicates greater relative tissue capacitance in roots than in leaves in these species.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Canadian Science Publishing
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  • 6
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    Water, Vol. 10, Pages 1200: Estimating the Infiltration Area for Concentrated Stormwater Spreading over Grassed and Other Slopes (2018)
    MDPI Publishing
    In: Water
    Details
    Publication Date: 2018-09-07
    Description: Water, Vol. 10, Pages 1200: Estimating the Infiltration Area for Concentrated Stormwater Spreading over Grassed and Other Slopes Water doi: 10.3390/w10091200 Authors: John S. Tyner Daniel C. Yoder Jacob Parker William C. Credille This research developed a new approach for calculating the area over which water spreads after being released from a confined conduit onto a sloped planar surface with defined roughness. In particular, the goal was to predict how stormwater would spread onto a sloped grass lawn after being discharged from a disconnected gutter downspout or through a parking lot curb cut. The need for this stems primarily from regulators increasingly requiring developers to infiltrate more of the runoff created by site development, but designers not having good tools for estimating the infiltration area associated with such “overflow” practices. The model is largely based on Manning’s equation applied at multiple cross-sectional areas of flow downslope, with additional modifications allowing the water to spread laterally. The model results were compared to laboratory experiments of water spreading across a roughened painted surface and two different artificial turfs. The new model predicted the wetting area with average absolute errors of 6.0% and 5.9% for a fine-bladed artificial turf and a coarse-bladed artificial turf, respectively. In addition, while validating the modeled flow spreading across a range of roughnesses, the model had an absolute error of 5.2% for a rough painted surface meant to represent unfinished concrete.
    Electronic ISSN: 2073-4441
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by MDPI Publishing
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  • 7
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    Six-year field performance of container-grown and bare-root black oak seedlings inoculated with Pisolithustinctorius and outplanted on two Ozark clear-cuts (1986)
    Canadian Science Publishing
    Details
    Publication Date: 1986-12-01
    Description: The effects of container culture and infection with Pisolithustinctorius (Pers.) Coker and Couch on growth and survival of black oak (Quercusvelutina Lam.) seedlings outplanted on two Missouri Ozark clear-cuts were examined over 6 years. Container-grown 1-0 seedlings exhibited height and diameter growth superior to bare-root stock, and mycorrhizal plants were taller than nonmycorrhizal plants during the first two to three field seasons. Thereafter, container-grown and bare-root, and mycorrhizal and nonmycorrhizal seedlings grew at comparable rates such that treatment differences in height and diameter had been greatly reduced 6 years after outplanting. Seedling growth and survival differed between sites, a response resulting from differential soil moisture availability and the nature of competing vegetation of the two planting sites. Shading by more abundant herbaceous and low woody vegetation on a comparatively mesic site likely resulted in greater mortality and less stem growth than on a xeric site during years 1 to 3. However, seedlings that grew to heights sufficient to overtop neighboring vegetation on the mesic site exhibited comparatively greater growth rates in years 4 to 6. As a result, after 6 years, the xeric site was occupied by a relatively large number of small seedlings, while the mesic site was characterized by fewer but larger seedlings.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Canadian Science Publishing
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  • 8
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    Early vegetation control for the regeneration of a single-cohort, intimate mixture of white spruce and trembling aspen on upland boreal sites (2010)
    Canadian Science Publishing
    Details
    Publication Date: 2010-03-01
    Description: In Canada’s boreal forest region, there is increasing demand for practical regeneration strategies that will recreate mixed stands of white spruce ( Picea glauca (Moench) Voss) and trembling aspen ( Populus tremuloides Michx.). In 2002, we implemented an experiment in both west-central Alberta and northeastern Ontario to better understand the effects of herbaceous and woody vegetation control on crop tree survival and growth, within the context of prescription development for the regeneration of a single-cohort, intimate mixture of spruce and aspen. After five growing seasons, good spruce growth, health, and survival were observed with 2 m radial treatments consisting of herbaceous and woody (i.e., complete) vegetation control centred on trees planted at 5 m spacing. These spruce were 4%–64% taller and 68%–178% larger in stem diameter than untended trees, leading to 167%–1166% gains in stem volume, and were at least equivalent to the same stock grown at 2.5 m spacing and provided with complete, continuous relief from competition. Removing only the woody vegetation within treated radii stimulated herbaceous competition, resulting in reduced survival and growth of spruce and reduced height of surrounding aspen. Early results suggest that spot treatments that provide 2–4 years of relief from herbaceous and woody competition may offer a practical strategy for growing spruce with aspen.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Canadian Science Publishing
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  • 9
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    Pressure–volume analysis of leaves of Robiniapseudoacacia L. with the sap expression and free transpiration methods (1988)
    Canadian Science Publishing
    Details
    Publication Date: 1988-09-01
    Description: Leaf tissue water relations parameters of well-watered and drought-stressed black locust (Robiniapseudoacacia L.) seedlings were compared using the sap expression and free transpiration pressure–volume analysis techniques. Osmotic potentials at full tissue hydration and at the turgor loss point were higher using the sap expression method for well-watered but not for drought-stressed seedlings. These differences appeared to be related to the percentage of water left uncollected during the sap expression procedure. Osmotic adjustment in response to drought was detected by both methods. Leaf relative water content at the turgor loss point and the symplastic water fraction did not differ between methods. The relationship between bulk tissue elastic modulus (E) and turgor potential estimated by both techniques was not significantly different, although E values derived from sap expression curves for well-watered seedlings were generally higher at a given turgor potential.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Canadian Science Publishing
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  • 10
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    Drought-induced leaf abscission and whole-plant drought tolerance of seedlings of seven black walnut families (1985)
    Canadian Science Publishing
    Details
    Publication Date: 1985-10-01
    Description: Whole-plant drought tolerance and leaf abscission in response to drought of 5-month-old, half-sib black walnut (Juglansnigra L.) seedlings representing seven geographic origins were examined. Seedlings were subjected to six different levels of drought stress and then reirrigated. Mortality, leaf abscission, and refoliation responses were measured. Only one of 404 seedlings actually died. Survival of stem cambial tissues at predawn leaf xylem pressure potential values as low as −4.0 MPa was associated with the capacity for drought-induced leaf abscission. The percentage of seedlings exhibiting at least 80% leaf abscission increased linearly as predawn leaf xylem pressure potential decreased from −1.5 to −3.5 MPa. Although substantial differences in leaf abscission among families were observed, these differences were not statistically significant (P ≤ 0.05). Eighteen percent of all seedlings exhibited some degree of refoliation upon recovery of plant water status. However, the cumulative area of regrowth foliage was insignificant in terms of its adaptive value for resumption of photosynthetic activity following stress relief.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Canadian Science Publishing
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