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Impact of the Presence of Foreign Bodies on Quality and Value of Oak Timber

Michalec Krzysztof, Wąsik Radosław, Gach Monika

Drewno : prace naukowe, doniesienia, komunikaty

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2023

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Vol. 66, nr 211

Art. no. 1644-3985.438.05

EN

The paper discusses the impact of the presence of foreign bodies on the quality and value of oak timber as raw material. During the study, 109 oak bolts and logs with a total volume of 142.52 m3 were measured and classified. The material for the study came from the Suchowice Forest District, within the Henryków Forestry Inspectorate (in the south-western part of Poland), and it was sampled from a tree stand located on the edge of the forest, where the largest concentration of rifle and artillery fire had occurred during World War II. As a result, the tree trunks contain significant amounts of shrapnel and projectiles. The length and diameter of each bolt and log were measured, and double classification was conducted: the first (I) classification took into account the presence of foreign bodies, whereas in the second (II) classification the presence of foreign bodies was disregarded. As a result of the conducted analyses, it was found that due to the presence of foreign bodies, all of the examined oak raw material was categorised as the worst quality class (D) timber. However, it was noted that during the second classification, where the presence of foreign bodies was not taken into account, a significant part of the raw material was upgraded to better quality classes, and only about 16% of wood remained in the worst, D class. Subsequently, it was calculated that the difference in the total value of the oak timber raw material classified by two methods amounted to approx. 204 thousand PLN (ca. € 43,514) - which was about 35% higher than the value calculated by the first method of classification.

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The occurrence and size of false heartwood in beech timber

Michalec Krzysztof, Wąsik Radosław, Gach Monika

Drewno : prace naukowe, doniesienia, komunikaty

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2022

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Vol. 65, nr 209

art. no. 1644-3985.385.08

EN

The aim of this study was to analyse the occurrence and size of false heartwood in beech timber over the lower and upper log faces. The research was carried out on 350 beech trunks where the presence of false heartwood was found on at least one of the log faces. The research material came from the Jarosław and Lesko Forest District (the Regional Directorate of the State Forests (RDSF) in Krosno) and the Pińczów Forest District (RDSF Radom). The following measurements were taken on selected logs: the mean bottom diameter, the mean upper diameter, the length of the analysed trunks, the maximum diameter of the false heartwood at both ends. As a result of the research, it was found that the maximum diameter of false heartwood on the beech log faces ranges from 30% to 40%, and a statistical test showed no significant difference in the extent of the defect between the lower and the upper face (t = -0.389; df = 612; p-value = 0.697). An analysis of the presence of the examined feature on the log faces showed that there were cases in which false heartwood appeared only over the lower face or only over the upper one. It was also noted that almost half of the examined logs had a larger diameter of the defect over the upper face than over the lower one. This study also examined the existence of a correlation between the diameter of the log face, log length and the percentage of the defect. The statistical test showed no significant correlation for both the lower and the upper face and the log length.

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Variability of selected macrostructure features, density and compression strength along the grain of “Tabórz” Scots pine wood (Pinus sylvestris L.)

Wąsik Radosław, Michalec Krzysztof, Barszcz Anna, Mudryk Krzysztof

Drewno : prace naukowe, doniesienia, komunikaty

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2020

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vol. 63, nr 205

171--182

EN

The aim of the study was to determine the variability of annual ring width, share of latewood, density and compression strength along the grain of “Tabórz” Scots pine wood (Pinus sylvestris L.). The wood samples for examination were obtained from three trunks of 260-year-old Scots pines felled in the Sosny Taborskie Nature Reserve. In total, 106 samples were obtained, with cross-sectional dimensions of 20 × 20 mm and a length of 30 mm along the grain. The mean values for all tested wood samples were as follows: annual ring width 1.28 mm, share of latewood 28.9%, wood density 0.487 g·cm-3, and compression strength 47.3 MPa. The least variability within trees was found for wood density and compressive strength along the grain. Very high positive correlation was found between wood density and compressive strength, and high positive correlations were found between share of latewood and wood density and between share of latewood and compressive strength. To the authors’ knowledge, the results presented here are the first empirical data published concerning the features of wood macrostructure, density and compression strength along the grain of the Tabórz Scots pine, the trunks of which are considered a valuable timber in Europe.

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The effect of stand origin on the wood structure of Norway spruce

Michalec Krzysztof, Wąsik Radosław, Barszcz Anna, Sowa Janusz M.

Drewno : prace naukowe, doniesienia, komunikaty

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2020

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vol. 63, nr 206

137--146

EN

A study was carried out to compare the annual ring width, latewood share and density of spruce wood from the north eastern a nd south w estern ranges of Norway spruce. Twelve trial plots were located in the north eastern range, while within the south w estern range eight trial plots were established in the Sudeten Mountains and twelve trial plots in the Carpathian Mountains. On ev ery trial plot fifteen spruce trees were chosen, from which increment cores were sampled using a Pressler borer. Next, the increment cores had their surfaces smoothed and measurements were made of the width of annual rings, latewood zones and the share of latewood. Then the cores were divided into 2 cm sections, for which the relative wood density was determined. The analyses indicate that annual rings were wider in trees growing within the north eastern range than in those from the south western range an d the Kruskal Wallis test showed the differences to be statistically significant. T he latewood share followed an opposite pattern: t he wood from the Mazury region had a higher proportion of latewood than the wood from the mountainous areas and the statist ical test again indicated that the differences were significant. The analys i s of wood density showed slight differences between the density of wood from the north eastern and south western ranges, but in this case the Kruskal Wallis test showed the differe nces to be statistically insignificant.