scholarly journals Variation of wood density in Turkish hazel (Corylus colurna L.) grown in the Czech Republic

2012 ◽  
Vol 58 (No. 4) ◽  
pp. 145-151 ◽  
Author(s):  
A. Zeidler
Keyword(s):  
Czech Republic ◽  
Wood Density ◽  
Basic Density ◽  
Ring Width ◽  
National Standards ◽  
Dry Density ◽  
Bottom Part ◽  
The Czech Republic ◽  
Mean Values ◽  
Density Values

The aim of this study was to investigate the wood density of Turkish hazel (Corylus colurna L.), an introduced species in the Czech Republic. Sample trees coming from a Czech site were tested for basic wood density and oven-dry density according to Czech national standards. Four sections were taken from each tree to evaluate the variability of wood density along the stem height and along the stem radius. The mean values for the basic density and the oven-dry density were 544 kg&middot;m<sup>&ndash;3 </sup>and 627 kg&middot;m<sup>&ndash;3</sup>, respectively. The results show that the highest density can be found in the bottom part of the tree, followed by a decline with the increasing height of the stem. For the radial direction from the pith to the bark, the pattern of density variability was more complex, reaching its highest value close to the cambium. Practically no correlation between annual ring width and density values was found out. &nbsp;

scholarly journals Proposed Methodology for the Calculation of Overview Distances at Level Crossings and the Inclusion Thereof in National Standards

2020 ◽  
Vol 12 (14) ◽  
pp. 5684
Author(s):  
Vladimír Ľupták ◽  
Maria Stopkova ◽  
Martin Jurkovič
Keyword(s):  
Czech Republic ◽  
Rational Solution ◽  
Geographical Location ◽  
National Standards ◽  
Technical Solution ◽  
Comprehensive Overview ◽  
Level Crossings ◽  
The Czech Republic ◽  
Current State ◽  
State Of Affairs

The aim of this article is to find a rational solution for increasing the safety of level crossings in the Czech Republic on the basis of a set of representative level crossings. The Czech Republic was deliberately chosen because of its geographical location, the number of level crossings on the network, and because, according to statistics from the Rail Safety Inspection Office, the country ranks as one of the highest for the number of accidents at level crossings. The rational solution being sought is one that achieves a balance between legislative, technical, and awareness-raising measures. In the practical part, great emphasis is placed on the assessment of the current state of Czech legislation. The identified discrepancies are resolved by adjusting calculations for overview distances and proposing changes to incorrect provisions. The main contribution of this paper is the comprehensive overview that it provides of level crossings and their safety. This overview includes a description of the current state of affairs, i.e., the number of level crossings, their location, classification, construction and type of equipment used, as well as an analysis of accidents and their frequency. The latter is in relation to the proposed construction and technical solution and subsequent assessment of the rationalisation possibilities and investments required to reconstruct or remove existing level crossings, thereby affecting the accident rate.

Climate signals from intra-annual wood density fluctuations in Abies durangensis

IAWA Journal ◽  
2019 ◽  
Vol 40 (2) ◽  
pp. 276-287 ◽  
Author(s):  
Marcos González-Cásares ◽  
Marín Pompa-García ◽  
Alejandro Venegas-González
Keyword(s):  
Wood Density ◽  
Drought Index ◽  
Growth Ring ◽  
Ring Width ◽  
Climatic Conditions ◽  
Density Fluctuations ◽  
Growth Ring Width ◽  
Density Values ◽  
Climate Signals ◽  
Hydroclimatic Variables

ABSTRACTOngoing climate change is expected to alter forests by affecting forest productivity, with implications for the ecological functions of these systems. Despite its great dendrochronological potential, little research has been conducted into the use of wood density as a proxy for determining sensitivity to climate variability in Mexico. The response of Abies durangensis Martínez, in terms of wood density and growth ring width, to monthly climatic values (mean temperature, accumulated precipitation and the drought index SPEI) was analyzed through correlation analysis. Abies durangensis presents a high response, in terms of radial growth, to climatic conditions. Tree-ring widths are more sensitive to hydroclimatic variables, whereas wood density values are more sensitive to temperature. In particular, mean (MeanD) and minimum (MND) wood density values are more sensitive to climate than maximum (MXD). We found very marked spatial variations that indicate that A. durangensis responds differently to drought conditions depending on the indices of density.

scholarly journals Differences in the perception of corporate culture as a motivational tool in the SME sector

2021 ◽  
Vol 92 ◽  
pp. 07032
Author(s):  
Iveta Kmecova ◽  
Michal Tlusty
Keyword(s):  
Czech Republic ◽  
Corporate Culture ◽  
Value Added ◽  
Employee Motivation ◽  
Primary Data ◽  
Online Questionnaire ◽  
The Czech Republic ◽  
Mean Values ◽  
Sample Test ◽  
Specific Calculations

Research background: The paper points out the differences in the motivation of employees in SMEs in terms of corporate culture as a motivational tool. The primary goal of the paper is to draw conclusions from hypotheses that analyse corporate culture as a motivational tool. Literary research outlines the issue of personnel activities focusing on the corporate culture as a motivational tool for SMEs in the Czech Republic. The practical part of the paper shows the whole course of specific calculations and evaluation of established hypotheses. At the end of the solution of each hypothesis, its rejection or confirmation is displayed, and this is justified by other methods that confirm this decision. Purpose of the article: The main purpose of the article is to confirm or reject predetermined hypotheses concerning small and medium-sized enterprises. A specific evaluation of the hypotheses will help to raise the profile of possible problems of small and medium-sized enterprises in the areas of employee motivation. Methods: Primary data for this article were obtained using an online questionnaire. The data are evaluated using a statistical method comparing the mean values of the samples, specifically using a statistical one-sample test. The research sample consisted of a total of 220 small and medium-sized enterprises (SMEs) in the Czech Republic. Findings & Value added: The results of the research will confirm or not confirm whether corporate culture is an important motivating tool for small and medium-sized enterprises and whether or not it differs depending on the division of enterprises according to different scales.

scholarly journals Planning of Safety of Cities and Territory from the Point of View of Population Protection in the Czech Republic

2020 ◽  
Vol 12 (22) ◽  
pp. 9487
Author(s):  
Jiri Pokorny ◽  
Barbora Machalova ◽  
Simona Slivkova ◽  
Lenka Brumarova ◽  
Vladimir Vlcek
Keyword(s):  
Czech Republic ◽  
Spatial Planning ◽  
Point Of View ◽  
Public Utility ◽  
National Standards ◽  
National Standard ◽  
Primary Role ◽  
The Czech Republic ◽  
Long Time ◽  
Spatial Plan

Ensuring territorial safety is one of the state’s main tasks, and the public administration plays a primary role in fulfilling it. The safety and sustainability of a territory is ensured by, inter alia, safety planning, including spatial planning. Spatial planning contains safety requirements for population protection. The requirements for ensuring the safety of the population included in the spatial plan vary significantly between countries. The existing population protection requirements contained in the spatial plan have been unsatisfactory for a long time. The main issue is that they are out of date and difficult to apply. The article presents a new proposed method for determining requirements for the protection of the population, which is based on evaluating the risks in the cities and territory. The specific population protection requirements are determined based on the resulting risks and their scaling. The requirements are classified as general when the territory is not faced with external risks or specific when there are such risks. The method is applied to the conditions of the Czech Republic. In terms of national standard specifics, there are requirements in areas of public infrastructure, public utility buildings, and public benefit measures. The method for determining population protection requirements can be considered applicable in a general form by various countries if the national standards specifics or other aspects are taken into account.

scholarly journals Effects of Fertilization on Wood Formation in Naturally Regenerated Juvenile Silver Birch in a Norway Spruce Stand in South Sweden

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 415
Author(s):  
Josefin A. Nilsson ◽  
Grace Jones ◽  
Charlotta Håkansson ◽  
Åsa Blom ◽  
Johan Bergh
Keyword(s):  
Cell Wall ◽  
Wood Density ◽  
Wall Thickness ◽  
Basic Density ◽  
Ring Width ◽  
Cell Wall Thickness ◽  
Silver Birch ◽  
Fertilizer Treatment ◽  
Age Difference ◽  
Stem Wood

This study investigates wood density and anatomy of juvenile silver birch stems in Sweden, grown in mixed conifer stands. Our aim is to investigate if fertilization provides increased growth, as well as an eventual reduction in stem wood density. Measurements of basic density, ring width, cell wall thickness, and vessels are analyzed for 20 birch trees. Bark to pith radial sections are analyzed using a light microscope and the freeware ImageJ to compare treatments and ages. The results show that trees with fertilizer treatment have wider growth rings and thinner cell wall thickness compared to unfertilized trees. The fertilized trees also have a lower cambium age at the same height and the same diameter, and a slightly lower stem mean density (420 kg m−3) than the unfertilized stems (460 kg m−3). Fertilizer is a significant determinant of density and cell wall thickness in nonlinear models. The fertilized trees have increased growth and reached a fixed diameter earlier. The age difference between the trees likely explains some of the differences in cell wall thickness. This study supports the use of fertilizer as a silvicultural option for increasing the growth rate of silver birch for a relatively small reduction of wood density.

scholarly journals Impact of Tree Age and Size on Selected Properties of Black Locust (Robinia pseudoacacia L.) Wood

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 634
Author(s):  
Szymon Bijak ◽  
Hubert Lachowicz
Keyword(s):  
Compression Strength ◽  
Tree Species ◽  
Black Locust ◽  
Robinia Pseudoacacia ◽  
Basic Density ◽  
Ring Width ◽  
Tree Age ◽  
Dry Density ◽  
Robinia Pseudoacacia L ◽  
The Impact

Black locust (Robinia pseudoacacia L.) is a non-native tree species that occupies a remarkable area in the forests of western Poland. It is mainly cultivated for the bee-keeping purposes as well as for its high quality wood. We investigated the impact of tree age and diameter on the selected structural, physical and mechanical attributes of wood of black locust that grows in conditions of mesic oligotrophic site. We analysed 200 samples originating from 18 trees that varied with age (38, 60 and 71 years old) and diameter (thin, medium and thick specimen selected according to Hartig’s method). Individual wood properties were determined along with corresponding European or Polish standards. Structural and mechanical attributes were determined for moisture of 12%. We found significant impact of tree age on tree-ring width, latewood proportion, density, oven-dry density, basic density, share of woody substance, porosity, as well as radial, tangential, longitudinal and volumetric shrinkage, compression strength parallel to grain, static bending, coefficient of compression strength parallel to grain and coefficient of static bending. The older the trees, the higher values of individual attributes were observed. In turn, the effect of tree diameter was less profound and no significant impact of that feature was found for latewood proportion, anisotropy and almost all of the shrinkage parameters. Thin trees exhibited the lowest values of the analysed parameters, while medium ones—the highest. In general, the highest technical quality of the investigated wood can be found in the youngest trees, whose wood characterises with the properties significantly exceeding native Polish tree species such as oak or beech.

scholarly journals German Shepherd Dog Milk Composition and Its Changes During Lactation

2016 ◽  
Vol 47 (1) ◽  
pp. 9-13
Author(s):  
A. Dokoupilová ◽  
I. Svobodová ◽  
H. Chaloupková ◽  
L. Kouřimská ◽  
B. Dvořáková ◽  
...  
Keyword(s):  
Czech Republic ◽  
Milk Composition ◽  
Service Dogs ◽  
German Shepherd ◽  
The Czech Republic ◽  
Mean Values ◽  
Total Solids ◽  
Milk Samples ◽  
German Shepherd Dog ◽  
Infra Red

Abstract Milk composition of nine lactating German Shepherd nursing females was studied. The experiment took place at the breeding facility of Police of the Czech Republic (breeding centre for service dogs in Domažlice) in days 2−30 of the females’ lactation. Females were given a commercial granulated feeding mixture (starter category). Canine milk samples were analyzed using an infra-red instrument MilkoScan FT 120. Calculated mean values for colostrum (day 2 postpartum) and normal milk (days 4−29 postpartum) were: 23.86 and 24.63% for total solids, 8.14 and 7.22% for protein, 6.04 and 5.76% for casein, 10.22 and 11.32% for fat, 3.40 and 4.48% for lactose. German Shepherd milk showed almost no variation in composition after day 4 of lactation. Differences observed between colostrum and normal milk composition were statistically insignificant but not for lactose. No significant differences in density and other composition parameters between colostrum and normal milk were identified.

scholarly journals A tree-ring perspective on temporal changes in the frequency and intensity of hydroclimatic extremes in the territory of the Czech Republic since 761 AD

2015 ◽  
Vol 11 (10) ◽  
pp. 1453-1466 ◽  
Author(s):  
P. Dobrovolný ◽  
M. Rybníček ◽  
T. Kolář ◽  
R. Brázdil ◽  
M. Trnka ◽  
...  
Keyword(s):  
Czech Republic ◽  
Tree Ring ◽  
Ring Width ◽  
Temporal Distribution ◽  
Temporal Changes ◽  
Human Society ◽  
Documentary Evidence ◽  
Data Set ◽  
Atlantic Sector ◽  
The Czech Republic

Abstract. It is generally accepted that anthropogenic-induced climate change may affect the frequency and intensity of hydrological extremes, together with a variety of subsequent impacts on ecosystems and human society. Proxy records that are absolutely dated and annually resolved are indispensable to a better understanding of temporal changes in the occurrence of floods and droughts. This contribution presents a new data set of 3194 oak (Quercus spp.) ring width samples from living trees and historical timbers, collected across the Czech Republic. A composite tree-ring width (TRW) chronology is developed that best captures the high-frequency extremes over the past 1250 years. The temporal distribution of negative and positive extremes is regular with no indication of clustering. The highest number of negative extremes was found in the 19th century, while positive extremes were most frequent in the 12th century. The lowest number of negative and positive extremes occurred in the 18th and 13th centuries respectively. Negative and positive TRW extremes were compared with the instrumental measurements back to 1805 AD, with documentary-based temperature and precipitation reconstructions from 1804 to 1500, and with documentary evidence before 1500 AD. Negative TRW extremes coincided with above-average March–May and June–August temperature means and below-average precipitation totals. Positive extremes coincided with higher summer precipitation, while temperatures were mostly normal. Mean sea level pressure (SLP) over the European/North Atlantic sector suggested drought for the negative oak TRW extremes, whereas the positive extremes corresponded to wetter conditions overall. More consistent patterns of synoptic SLP were found for negative rather than for positive extremes. Reasons for the possible offset between the oak-based hydroclimatic extremes and their counterparts from meteorological observations and documentary evidence may be manifold and emphasize the need for multi-proxy approaches.

scholarly journals Influence of site conditions and silvicultural practice on the wood density of Scots pine (Pinus sylvestris L.) – a case study from the Doksy locality, Czech Republic

2017 ◽  
Vol 63 (No. 10) ◽  
pp. 457-462
Author(s):  
Schönfelder Ondřej ◽  
Zeidler Aleš ◽  
Borůvka Vlastimil ◽  
Bílek Lukáš
Keyword(s):  
Czech Republic ◽  
Pinus Sylvestris ◽  
Wood Density ◽  
Scots Pine ◽  
Tree Species ◽  
Site Conditions ◽  
The Czech Republic ◽  
Clear Cutting ◽  
Regeneration Period ◽  
Coniferous Tree Species

After spruce, the Scots pine (Pinus sylvestris Linnaeus) is the second most important commercial coniferous tree species in the Czech Republic. However, we are finding out that awareness of the variability of properties, and possibilities to affect them, are noticeably small for this type of tree species in our conditions. The goal of this study is to primarily evaluate the importance of site conditions, silvicultural measures and other factors for the density of Scots pine wood in the Doksy locality in the Czech Republic. The Doksy locality is represented by three forest stands with different silvicultural history. Samples were taken from each stand, the basal and central parts of which were subsequently processed for test samples with dimensions of 20 × 20 × 30 mm. Wood density at 12% moisture content was ascertained in the test samples. The highest density value of 0.541 g·cm<sup>–3</sup> was reached in a stand that is regenerated using the shelterwood method with long regeneration period, and the lowest density value of 0.488 g·cm<sup>–3</sup> was recorded in a stand that was regenerated using the clear-cutting method. From a forestry perspective, it can be further stated that the wood density of Scots pine is also affected by the site conditions and position of samples in the trunk.

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