scholarly journals The influence of competition and species mixture on plantation-grown white spruce: Growth and foliar nutrient response after 20 years

2014 ◽  
Vol 90 (01) ◽  
pp. 70-79 ◽  
Author(s):  
Breanne A. Neufeld ◽  
Dave M. Morris ◽  
Nancy Luckai ◽  
Douglas E.B. Reid ◽  
F. Wayne Bell ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Basal Area ◽  
White Spruce ◽  
Mixed Stands ◽  
Density Control ◽  
Foliar Nutrient ◽  
Thinning Operations ◽  
Species Specific ◽  
Foliar Sampling ◽  
Physical And Chemical

A 20-year-old experimental white spruce plantation was used to identify key stand (neighbourhood competition) and soil (physical and chemical properties) factors influencing spruce growth (Periodic Basal Area Increment) and foliar nutrients. Total and species-specific competition was estimated using Hegyi’s distance-dependent index for 39 individual spruce trees. Twelve trees, covering the range of total HCI (2 to 8) and aspen competition (0% to >75%), were selected for repeated (May through October) foliar sampling. Spruce PBAI declined approximately 10% for each additional unit of total HCI; species did not significantly affect this decline. Increasing aspen presence significantly influenced spruce foliar N (1.17% to 1.31%), P (0.15% to 0.23%), and K (0.68% to 0.88%), but led to declines in Ca (0.81% to 0.48%). Multiple linear regression indicated that soil carbon (partial r2 = 0.386) and available soil moisture (partial r2 = 0.131) together explained more of the variation in spruce growth than did competition factors alone (partial r2 = 0.251). The results suggest that, at this stage of stand development, precommercial thinning operations should focus on density control and inter-tree spacing, while retaining an aspen component resulting in well-spaced, free-growing mixed stands of white spruce and aspen.

scholarly journals Short Rotation Eucalypts: Opportunities for Biochar

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 314 ◽  
Author(s):  
Donald L. Rockwood ◽  
Martin F. Ellis ◽  
Ruliang Liu ◽  
Fengliang Zhao ◽  
Puhui Ji ◽  
...  
Keyword(s):  
Net Present Value ◽  
Organic Fertilizer ◽  
Chemical Properties ◽  
Basal Area ◽  
Individual Tree ◽  
Short Rotation Woody Crops ◽  
Short Rotation ◽  
Naturally Occurring ◽  
Tree Leaf ◽  
Physical And Chemical

Eucalypts can be very productive when intensively grown as short rotation woody crops (SRWC) for bioproducts. In Florida, USA, a fertilized, herbicided, and irrigated cultivar planted at 2471 trees/ha could produce over 58 green mt/ha/year in 3.7 years, and at 2071 trees/ha, its net present value (NPV) exceeded $750/ha at a 6% discount rate and stumpage price of $11.02/green mt. The same cultivar grown less intensively at three planting densities had the highest stand basal area at the highest density through 41 months, although individual tree diameter at breast height (DBH) was the smallest. In combination with an organic fertilizer, biochar improved soil properties, tree leaf nutrients, and tree growth within 11 months of application. Biochar produced from Eucalyptus and other species is a useful soil amendment that, especially in combination with an organic fertilizer, could improve soil physical and chemical properties and increase nutrient availability to enhance Eucalyptus tree nutrition and growth on sandy soils. Eucalypts produce numerous naturally occurring bioproducts and are suitable feedstocks for many other biochemically or thermochemically derived bioproducts that could enhance the value of SRWCs.

Site index, site quality, and foliar nutrients of trembling aspen: relationships and predictions

1998 ◽  
Vol 28 (12) ◽  
pp. 1743-1755 ◽  
Author(s):  
Han YH Chen ◽  
Karel Klinka ◽  
Richard D Kabzems
Keyword(s):  
Forest Floor ◽  
Mineral Soil ◽  
Chemical Properties ◽  
Site Index ◽  
Foliar Nutrients ◽  
Trembling Aspen ◽  
Soil Model ◽  
Foliar Nutrient ◽  
Physical And Chemical ◽  
And Chemical Properties

To examine the relationships between trembling aspen (Populus tremuloides Michx.) productivity, environmental attributes, and foliar nutrients and to make accurate predictions of trembling aspen productivity, we sampled 60 naturally established, fire-originated, and even-aged trembling aspen stands in northern British Columbia. Trembling aspen site index significantly varied with latitude, elevation, aspect, slope position, edatopes, some forest floor and mineral soil physical and chemical properties, and concentrations of some foliar nutrients. To predict site index, we developed multiple linear regression models using climatic variables, topographic properties, edatopes, soil physical and chemical properties, or foliar nutrients as predictors. Model accountability for variation of site index differed in decreasing order from soil model, climatic model, forest floor model, foliar nutrient model, edatope model, topographic model, to mineral soil model. Examined by the test data set, all models were unbiased, but they had different levels of precision in prediction in decreasing order from edatope model, soil model, forest floor model, mineral soil model, foliar nutrient model, climatic model, to topographic model. The soil and foliar nutrients models may provide insight into ecosystem processes, but the models using climatic variables and topographic properties or edatopes as predictors are recommended for predicting trembling aspen site index.

Altered forest composition and soil properties of historic charcoal hearths in southeastern Pennsylvania

1995 ◽  
Vol 25 (5) ◽  
pp. 687-696 ◽  
Author(s):  
Carl J. Mikan ◽  
Marc D. Abrams
Keyword(s):  
Chemical Properties ◽  
Basal Area ◽  
Exchange Capacity ◽  
Forest Composition ◽  
Charcoal Production ◽  
Exchangeable Ca ◽  
Quercus Species ◽  
Stump Sprouting ◽  
Physical And Chemical ◽  
Charcoal Hearths

This study related age structure and composition of forests in southeastern Pennsylvania to edaphic properties caused by the activities of a local charcoal iron furnace from the late 18th to the late 19th century. Forests surrounding charcoal hearths were harvested on 20- to 30-year rotations to supply wood for charcoal production in earthmound kilns. Charcoal hearths were created by a recurring cycle of disturbance, including the removal of established vegetation, intense heat, and the deposition of charcoal. Thirty-eight hearths of Hopewell Furnace National Historic Site were examined to describe differences in vegetation relative to surrounding forests that have developed since the cessation of charcoal production in 1883. Hearth forests were significantly younger than surrounding forests, with lower tree density and basal area, decreased sapling and shrub abundance, and higher herbaceous cover. Compositional differences on charcoal hearths included decreased importance of several Quercus species and ericaceous shrubs and increased importance of Liriodendrontulipifera L. Results of this study indicated that the initial effect of charcoal production was the prevention of stump sprouting and a delay in recolonization following disturbance due to extreme soil physical and chemical properties. Failure of hearth seedlings to recruit into larger size classes, age–diameter relationships of Liriodendrontulipifera L. trees, and the failure of calcifuge species to reestablish similar cover on charcoal hearths suggested that unfavorable properties of charcoal soils continue to negatively affect long-term productivity. Relative to nonhearth soils, large, significant differences in soil pH, cation exchange capacity, base saturation, and exchangeable Ca, Mg, and K indicated that continuing inhibition of woody plants on charcoal hearths may be related to alterations in soil chemistry that have persisted for 110 years.

scholarly journals Shaping the leaf microbiota: plant–microbe–microbe interactions

2020 ◽  
Author(s):  
Vasvi Chaudhry ◽  
Paul Runge ◽  
Priyamedha Sengupta ◽  
Gunther Doehlemann ◽  
Jane E Parker ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Chemical Properties ◽  
Microbial Colonization ◽  
Host Immune System ◽  
Natural Habitats ◽  
Microbe Interactions ◽  
Pathogenic Microbes ◽  
Species Specific ◽  
Physical And Chemical ◽  
The Impact

Abstract The aerial portion of a plant, namely the leaf, is inhabited by pathogenic and non-pathogenic microbes. The leaf’s physical and chemical properties, combined with fluctuating and often challenging environmental factors, create surfaces that require a high degree of adaptation for microbial colonization. As a consequence, specific interactive processes have evolved to establish a plant leaf niche. Little is known about the impact of the host immune system on phyllosphere colonization by non-pathogenic microbes. These organisms can trigger plant basal defenses and benefit the host by priming for enhanced resistance to pathogens. In most disease resistance responses, microbial signals are recognized by extra- or intracellular receptors. The interactions tend to be species specific and it is unclear how they shape leaf microbial communities. In natural habitats, microbe–microbe interactions are also important for shaping leaf communities. To protect resources, plant colonizers have developed direct antagonistic or host manipulation strategies to fight competitors. Phyllosphere-colonizing microbes respond to abiotic and biotic fluctuations and are therefore an important resource for adaptive and protective traits. Understanding the complex regulatory host–microbe–microbe networks is needed to transfer current knowledge to biotechnological applications such as plant-protective probiotics.

Susceptibility of balsam fir to spruce budworm defoliation as affected by thinning

1979 ◽  
Vol 9 (3) ◽  
pp. 428-435 ◽  
Author(s):  
Gregory W. Crook ◽  
Paul E. Vézina ◽  
Yvan Hardy
Keyword(s):  
Forest Type ◽  
Coniferous Forest ◽  
Basal Area ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Stand Age ◽  
Forest Types ◽  
Mixed Stands ◽  
Number Of Stems

Spruce budworm, Choristoneurafumiferana (Clemens), defoliation of balsam fir, Abiesbalsamea (L.) Mill., was studied in thinned stands of the Lower St. Lawrence region of Quebec. The object of the study was to quantify defoliation levels in treated and control plots in order to determine what effect, if any, thinning had on the susceptibility of balsam fir.Three main forest types were studied: (a) coniferous, (b) mixed, and (c) hardwood with a fir understory. The coniferous forest type was subdivided into three types: (1) pure balsam fir; (2) balsam fir – white spruce, Piceaglauca (Moench) Voss; (3) balsam fir – hardwoods. Defoliation levels were estimated using two current techniques: the Dorais–Hardy (1976) and the Fettes (1950) methods.Susceptibility of balsam fir to spruce budworm defoliation was not affected after thinning in coniferous and hardwood forest types; however, susceptibility was increased in mixed stands when part of the hardwood cover was removed. In any situation, defoliation of fir was found to be more intense with an increase of the basal area of the coniferous species (balsam fir, red spruce, Picearubens Sarg., and white spruce) while an increase of the basal area of hardwoods resulted in lower defoliation levels; likewise, a higher number of stems per hectare brought higher defoliation levels of fir. Defoliation was also found to vary with stand composition; susceptibility of fir in the three main cover types decreased in the following order: (a) coniferous, (b) mixed, (c) hardwood. Stand age was not a factor influencing the susceptibility of balsam fir for the two age classes studied (30 and 50 years).

Statistical criteria of stellar population types

1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska
Keyword(s):  
Stellar Population ◽  
Chemical Properties ◽  
Spectrophotometric Study ◽  
Physical And Chemical Properties ◽  
Population Type ◽  
The Galaxy ◽  
Distribution Parameters ◽  
Physical And Chemical ◽  
Statistical Criteria ◽  
And Chemical Properties

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.

Biophysical Measurement of Molecular Weight of Foot-and-Mouth Disease RNA Fragments

1974 ◽  
Vol 32 ◽  
pp. 262-263
Author(s):  
Sydney S. Breese ◽  
Howard L. Bachrach
Keyword(s):  
Chemical Properties ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Distilled Water ◽  
Bovine Plasma ◽  
Mouth Disease Virus ◽  
Foot And Mouth ◽  
Carbon Coated ◽  
Rna Fragments ◽  
Physical And Chemical

Continuing studies on the physical and chemical properties of foot-and-mouth disease virus (FMDV) have included electron microscopy of RNA strands released when highly purified virus (1) was dialyzed against demlneralized distilled water. The RNA strands were dried on formvar-carbon coated electron microscope screens pretreated with 0.1% bovine plasma albumin in distilled water. At this low salt concentration the RNA strands were extended and were stained with 1% phosphotungstic acid. Random dispersions of strands were recorded on electron micrographs, enlarged to 30,000 or 40,000 X and the lengths measured with a map-measuring wheel. Figure 1 is a typical micrograph and Fig. 2 shows the distributions of strand lengths for the three major types of FMDV (A119 of 6/9/72; C3-Rezende of 1/5/73; and O1-Brugge of 8/24/73.

Tailoring microstructures of materials through biomimetics

1993 ◽  
Vol 51 ◽  
pp. 500-501
Author(s):  
Mehmet Sarikaya ◽  
Ilhan A. Aksay
Keyword(s):  
Chemical Properties ◽  
Design And Synthesis ◽  
Structure Sensitive ◽  
Macro Scale ◽  
Methods Of Synthesis ◽  
Successive Level ◽  
Engineering Materials ◽  
Physical And Chemical ◽  
And Chemical Properties ◽  
Synthesis Of Materials

Biomimetics involves investigation of structure, function, and methods of synthesis of biological composite materials. The goal is to apply this information to the design and synthesis of materials for engineering applications.Properties of engineering materials are structure sensitive through the whole spectrum of dimensions from nanometer to macro scale. The goal in designing and processing of technological materials, therefore, is to control microstructural evolution at each of these dimensions so as to achieve predictable physical and chemical properties. Control at each successive level of dimension, however, is a major challenge as is the retention of integrity between successive levels. Engineering materials are rarely fabricated to achieve more than a few of the desired properties and the synthesis techniques usually involve high temperature or low pressure conditions that are energy inefficient and environmentally damaging.In contrast to human-made materials, organisms synthesize composites whose intricate structures are more controlled at each scale and hierarchical order.

Response of corn (Zea mays L.) to various organic-based fertilizers in marginal upland of Sta. Rita, Samar

2017 ◽  
pp. 31-43
Author(s):  
Berta Ratilla ◽  
Loreme Cagande ◽  
Othello Capuno
Keyword(s):  
Block Design ◽  
Management Strategies ◽  
Chemical Properties ◽  
Organic Fertilizers ◽  
Growth And Yield ◽  
Physical And Chemical Properties ◽  
Total N ◽  
Randomized Complete Block Design ◽  
Physical And Chemical ◽  
And Chemical Properties

Organic farming is one of the management strategies that improve productivity of marginal uplands. The study aimed to: (1) evaluate effects of various organic-based fertilizers on the growth and yield of corn; (2) determine the appropriate combination for optimum yield; and (3) assess changes on the soil physical and chemical properties. Experiment was laid out in Randomized Complete Block Design, with 3 replications and 7 treatments, namely; T0=(0-0-0); T1=1t ha-1 Evans + 45-30-30kg N, P2O5, K2O ha-1; T2=t ha-1 Wellgrow + 45-30-30kg N, P2O5, K2O ha-1; T3=15t ha-1 chicken dung; T4=10t ha-1 chicken dung + 45-30-30kg N, P2O5, K2O ha-1; T5=15t ha-1 Vermicast; and T6=10t ha-1 Vermicast + 45-30-30kg N, P2O5, K2O ha-1. Application of organic-based fertilizers with or without inorganic fertilizers promoted growth of corn than the control. But due to high infestation of corn silk beetle(Monolepta bifasciata Horns), its grain yield was greatly affected. In the second cropping, except for Evans, any of these fertilizers applied alone or combined with 45-30-30kg N, P2O5, K2O ha-1 appeared appropriate in increasing corn earyield. Soil physical and chemical properties changed with addition of organic fertilizers. While bulk density decreased irrespective of treatments, pH, total N, available P and exchangeable K generally increased more with chicken dung application.

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