scholarly journals Static stability of forest stands in the seventh altitudinal vegetation zone in Slovakia

2012 ◽  
Vol 49 (No. 10) ◽  
pp. 474-481 ◽  
Author(s):  
B. Konôpka ◽  
J. Konôpka
Keyword(s):  
Slenderness Ratio ◽  
Static Stability ◽  
Mountain Forest ◽  
Practical Application ◽  
Tatra Mountains ◽  
Forest Stands ◽  
Vegetation Zone ◽  
Site Class ◽  
The Mean ◽  
Empirical Material

Models evaluating static stability (resistance to breaking or uprooting of trees caused by wind, snow or ice) of forest stands in the seventh altitudinal vegetation zone were determined. The empirical material came from 180 research plots (High Tatra and Low Tatra Mountains) established within the research project Research on methods for mountain forest management based on sustainable Development. Static stability was characterized by the slenderness ratio that was calculated from the mean height and diameter of target trees. Then the particular forest stands were categorized with regard to slenderness ratio, mean diameter and absolute site class using either tables or graphic models. Particularly, four static stability classes were made up: 1 – very good, 2 – good, 3 – sufficient, and 4 – insufficient. Practical application of the models is shown for forest stands grown in the area of Vajsková and Lomnistá valleys.

Germination and initial growth of triticale seeds under stationary magnetic fields

2014 ◽  
Vol 2 (2) ◽  
pp. 72-79 ◽  
Author(s):  
Mercedes Florez ◽  
Elvira Martinez ◽  
Victoria Carbonell
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Seed Vigor ◽  
Initial Growth ◽  
Practical Application ◽  
Biochemical Processes ◽  
Mean Germination Time ◽  
Nutrition Value ◽  
The Mean ◽  
Growth Of Seedlings

The main objective of this study is to determine the effects of 125 mT and 250mT magnetic treatment on the germination and initial growth of triticale seeds. This objective has a practical application in agriculture science: early growth of triticale. An increase in the percentage and rate of germination of seeds and a stimulation of growth of seedlings as positive response to magnetic field treatment in rice, wheat, maize and barley seeds have been found in previous studies. Germination tests were carried out under laboratory conditions by exposing triticale seeds to magnetic field for different times. The effect was studied by exposure of seeds prior sowing. The mean germination time were reduced for all the magnetic treatments applied. Most significant differences were obtained for time of exposure of 1 and 24 hours and maximum reductions was 12%. Furthermore, seedlings from magnetically treated seeds grew taller than control. The longest mean total length was obtained from seedlings exposed to 125 and 250 mT for 24 hours. External magnetic fields are assumed to enhance seed vigor by influencing the biochemical processes by stimulating activity of proteins and enzymes. Numerous studies suggested that magnetic field increases ions uptake and consequently improves nutrition value.

Consideration of Environmentally Assisted Fatigue in Austenitic Stainless Steel: Calculation and Practical Application

2012 ◽  
Author(s):  
Sven H. Reese ◽  
Johannes Seichter ◽  
Dietmar Klucke
Keyword(s):  
Primary Circuit ◽  
Stress And Strain ◽  
Loading Conditions ◽  
Practical Application ◽  
Circuit Component ◽  
Detailed Assessment ◽  
The Mean ◽  
Fatigue Evaluation ◽  
Assessment Procedures

The influence of LWR coolant environment to the lifetime of materials has been discussed recent years. Nowadays the consideration of environmentally assisted fatigue is under consideration in Codes and Standards like ASME and the German KTA Rules (e.g. Standard No. 3201.2 and Standard No. 3201.4) by means of so called attention thresholds. Basic calculation procedures in terms of quantifying the influence of LWR coolant environment by the Fen correction factor were proposed by Higuchi and others and are given in NUREG/CR-6909. This paper deals with the application of the proposed assessment procedures of ANL and the application to plant conditions. Therefore conservative assessment procedures are introduced without assuming the knowledge of detailed stress and strain calculations or temperature transients. Additionally, detailed assessment procedures based on Finite-Element calculations, respecting in-service temperature measurements including thermal reference transients and complex operational loading conditions are carried out. Fatigue evaluation of a PWR primary circuit component is used in order to evaluate the influence of plant like conditions numerically. Conclusions regarding the practical application are drawn by means of comparing the ANL approach considering laboratory conditions, conservative assessment procedures for the determination of cumulative fatigue usage factors of plant components and detailed assessment procedures. Plant like loading conditions, complex component geometries, loading scenarios and reference temperature transients shall be taken into account. Practical issues like the determination of the mean temperature or the strain rate have to be considered adequately.

Biosurfactant production and its effects on solubilization activity of phenanthrene: a longitudinal study

2016 ◽  
Vol 74 (3) ◽  
pp. 580-585
Author(s):  
Masoumeh Golshan ◽  
Maryam Dastoorpour ◽  
Roshanak Rezaei Kalantary
Keyword(s):  
Time Course ◽  
Inoculum Size ◽  
Biosurfactant Production ◽  
Practical Application ◽  
Time Intervals ◽  
Initial Inoculum ◽  
Bacterial Inoculum ◽  
Polycyclic Aromatic ◽  
The Mean ◽  
Time Course Study

Pseudomonas facilis and Pseudomonasspp., isolated on the basis of its ability to grow on polycyclic aromatic hydrocarbon, was assayed for biosurfactant production (BP) potentials by measuring the surface tension (ST) of the culture supernatant at different time intervals. The strains in three levels of initial inoculum size (OD600 nm = 0.5, 1, 1.5) were added to medium to determine if bacterial inoculum size affects solubilization of phenanthrene (PHE).The result showed that although the two strains reduced the mean ST to less than 34.12 mN m−1 at the end of day 6, mean solubilization activity of PHE reached 77.05 mg L−1 on the sixth day. There was a significant increase in BP over time (P = 0.008); reaching its peak, 157.84 mg L−1, at the end of the sixth day. Mean solubilization activity of PHE was not significantly different for the two strains (P = 0.216). The time-course study revealed that the ST reduction and BP potential was enhanced as inoculation size increased, leading to higher PHE solubility during the incubation time. However, the trend of increase in PHE solubility was not totally in the same way to cell growth and BP. It may be suggested that more bacterial density needs to be inoculated for practical application of effective bioremediation.

Red-Breasted Nuthatches Detect Early Increases in Spruce Budworm Populations

1990 ◽  
Vol 7 (2) ◽  
pp. 81-83 ◽  
Author(s):  
Hewlette S. Crawford ◽  
Daniel T. Jennings ◽  
Timothy L. Stone
Keyword(s):  
New Hampshire ◽  
Spruce Budworm ◽  
High Density ◽  
Forest Stands ◽  
Inexpensive Method ◽  
The Mean

Abstract Early suppression of increasing spruce budworm populations is essential to prevent epidemics; however, early changes in budworm numbers are difficult to detect. An effective and inexpensive method to detect early increases is needed. Red-breasted nuthatches eat more spruce budworm larvae and pupae as the insect increases in number. We estimated the number of large larvae in Maine and northern New Hampshire forest stands in 1982 and 1983 by determining the number of these larvae in the birds' stomachs. When the mean number of spruce budworm in the stomach approached 1.7, budworm populations were nearing high density and could be expected to cause severe defoliation the following year. North. J. Appl. For. 7:81-83, June 1990.

COMPARISONS OF METHODS OF pH DETERMINATION FOR ORGANIC TERRAIN SURVEYS

1973 ◽  
Vol 53 (2) ◽  
pp. 177-183 ◽  
Author(s):  
W. STANEK
Keyword(s):  
Ph Value ◽  
Liquid Limit ◽  
Natural State ◽  
Confidence Limits ◽  
Practical Application ◽  
Oven Drying ◽  
Ph Values ◽  
Coefficients Of Variation ◽  
The Mean ◽  
A Site

pH values were measured on peat samples taken from a water-logged peatland in Ontario, from April 1970 to April 1971, by 14 procedures: on fresh peat and groundwater, in their natural state; and on combinations of hand-squeezed, air-dried, and oven-dried peat, each rewetted to liquid limit with either distilled H2O, N/100 CaCl2∙2H2O, N/10 KCl, or N/10 CaCl2∙2H2O. Groundwater showed the highest mean pH (4.0), followed by hand-squeezed peat rewetted with distilled H2O (3.8), then fresh peat (3.6). In comparison with fresh peat, air and oven drying lowered the mean pH value by 0.1 and 0.2 units, rewetting with N/100 CaCl2∙2H2O, by 0.4; N/10 KCl, by 0.5; and N/10 CaCl2∙2H2O, by 0.6 units approximately. The coefficients of variation and the confidence limits showed, for practical application, that all methods were equally reliable and that pH determined at any time of the year validly characterized a site.

scholarly journals Impact of risk factor management on the sanitary condition of Norway spruce (Picea abies [L.] Karst.) pure stands in Latvia

2014 ◽  
Vol 60 (No. 5) ◽  
pp. 181-189
Author(s):  
J. Rūba ◽  
O. Miezīte ◽  
S. Luguza
Keyword(s):  
Risk Factors ◽  
Risk Factor ◽  
Spatial Structure ◽  
Health State ◽  
Anthropogenic Factor ◽  
Forest Stands ◽  
Risk Factor Management ◽  
Sanitary Condition ◽  
Young Forest ◽  
Empirical Material

In management of young forest stands, it is often the case in forestry that several risk factors, biotic, abiotic and anthropogenic ones, have to be dealt with. An anthropogenic factor is of great importance in management of forests, because humans, using ecosystems for their needs, still have to maintain the spatial structure of the forest and prevent the worsening of the health state. Covering all territory of Latvia, empirical material was gathered in 25 pure stands. To find out how neighbouring stands impact the young forest stands of spruce, the location in forest array was detected. In identifying the risk factors, attention should be paid to the shape of compartment and its location in forest array. A correlation between the occurrence and intensity of damage caused by cloven-hoofed game is relevant r<sub>fact </sub>= 0.988 &gt; r<sub>crit </sub>= 0.088 with 95% probability. Also the occurrence and intensity of Lophophacidium hyperboreum Lagerb., and damage by Heterobasidion spp. are relevant r<sub>fact </sub>= 0.991 &gt; r<sub>crit </sub>= 0.062 and r<sub>fact </sub>= 0.981 &gt; r<sub>crit </sub>= 0.088 with of 95% probability. &nbsp;

scholarly journals Derivation of target stocking for forests of Norway spruce vegetation zone in Slovakia

2008 ◽  
Vol 53 (No. 8) ◽  
pp. 352-358 ◽  
Author(s):  
M. Moravčík
Keyword(s):  
Norway Spruce ◽  
Natural Regeneration ◽  
Tree Height ◽  
Static Stability ◽  
Vegetation Coverage ◽  
Social Functions ◽  
Ecological Functions ◽  
Vegetation Zone ◽  
Crown Length ◽  
Forest Limit

The present paper deals with derivation of target stocking in forests of Norway spruce vegetation zone. Target stocking in forests with prevailing ecological and social functions is the stocking when the forest fulfils demanded functions in the best way. For forests in the Norway spruce vegetation zone target stocking was derived by original procedures as an optimum stocking in harmonization of demands on the fulfilment of ecological functions (especially erosion control, hydrological and water protection ones), securing static stability and preconditions for the formation and growth of natural regeneration. We investigated the relations between stocking and indicators of static stability (slenderness coefficient and ratio of crown length to tree height), natural regeneration phases, ground and non-wood vegetation coverage and natural regeneration coverage. The most favourable status of these indicators was found out in stocking 0.7 and in the upper forest limit 0.6.

scholarly journals Structure and development of forest stands on permanent research plots in the Krkonoše Mts.

2010 ◽  
Vol 56 (No. 11) ◽  
pp. 518-530
Author(s):  
S. Vacek ◽  
Z. Vacek ◽  
L. Bílek ◽  
I. Nosková ◽  
O. Schwarz
Keyword(s):  
Species Composition ◽  
Tree Species ◽  
Vertical Structure ◽  
Forest Stand ◽  
Forest Stands ◽  
Vegetation Zone ◽  
Aggregation Index ◽  
Tree Species Composition ◽  
Results Management ◽  
Management Recommendations

The research is focused on structure and development of forest stands from 5th to 8th forest vegetation zone in the Krkono&scaron;e Mts. The forest stand diversity according to tree species composition and representation, horizontal and vertical structure was evaluated by using following indices: Clark-Evans aggregation index (Clark, Evans 1954), standardised Arten-profil index (Pretsch 2005) and index of complex diversity after Jaehne, Dohrenbusch (1997). Growth model SIBYLA (Fabrika, Ďursk&yacute; 2005) was used for visualizations and growth predictions of forest stands on particular plots. Based on research results, management recommendations were evaluated.

scholarly journals Contribution of regeneration on dead wood to the spontaneous regeneration of a mountain forest

2012 ◽  
Vol 50 (No. 9) ◽  
pp. 405-414 ◽  
Author(s):  
K. Ježek
Keyword(s):  
Natural Regeneration ◽  
Dead Wood ◽  
Nature Reserve ◽  
Soil Surface ◽  
Mountain Forest ◽  
Silver Fir ◽  
Mountain Forests ◽  
Managed Forest ◽  
Vegetation Zone ◽  
Spontaneous Regeneration

In the Moravian-Silesian Beskids in the beech/spruce forest vegetation zone, the amount of dead wood was determined (pieces of wood and stumps) in five sample plots in a managed forest and in three plots in the National Nature Reserve (NNR) Kněhyně-Čertův Ml&yacute;n. In plots situated in the managed forest, 22 to 50 m<sup>3</sup>/haof lying wood was found. In the reserve, the volume of fallen wood ranged from 29 to 144 m<sup>3</sup>/ha. The number of stumps in sample plots in the managed forest ranged from 530 to 980 per ha. In the reserve, the number of new stumps did not increase any more and only stumps from the period before the NNR declaration occurred. On the dead wood, spruce is regenerated nearly exclusively. In the managed forest and in the NNR, the number of regenerated spruce plants ranged from 5,000 to 16,000 and from 600 to 4,500 per ha, respectively. In plots where the sufficient amount of dead lying wood and stumps occurred, the proportion of spruce plants regenerated on the substrates amounted to even 75%. Other species (beech and silver fir) regenerated only on the soil surface. A sufficient amount of dead wood for the germination of seedlings can significantly ensure the natural regeneration of spruce in mountain forests.

Sensitivity of Perturbation Variance and Fluxes in Turbulent Jets to Changes in the Mean Jet

2004 ◽  
Vol 61 (21) ◽  
pp. 2644-2652
Author(s):  
Brian F. Farrell ◽  
Petros J. Ioannou
Keyword(s):  
Stochastic Model ◽  
Storm Track ◽  
Turbulent Jets ◽  
Static Stability ◽  
Structure Change ◽  
Synoptic Scale ◽  
Single Jet ◽  
The Mean ◽  
Arbitrary Change ◽  
Jet Structure

Abstract Synoptic-scale eddy variance and fluxes of heat and momentum in midlatitude jets are sensitive to small changes in mean jet velocity, dissipation, and static stability. In this work the change in the jet producing the greatest increase in variance or flux is determined. Remarkably, a single jet structure change completely characterizes the sensitivity of a chosen quadratic statistical quantity to modification of the mean jet in the sense that an arbitrary change in the jet influences a chosen statistical quantity in proportion to the projection of the change on this single optimal structure. The method used extends previous work in which storm track statistics were obtained using a stochastic model of jet turbulence.

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