Maderas. Ciencia y Tecnología 2019-09-13T10:18:12-03:00 Ruben A. Ananias. Open Journal Systems <p>&nbsp;</p> <p>&nbsp;</p> <table style="margin-top: -250px; width: 1025px; height: 672px;"> <tbody> <tr> <td style="width: 30%;"><strong><span style="color: #ffffff; text-align: center;"><img src="/public/site/images/visepul/cover-3d-21(3)1.png"></span></strong></td> <td style="width: 30%;"> <p><img style="width: 30px;" src="" alt=""> <a href="">Full Text PDF</a><br> <img style="width: 30px;" src="" alt=""> <a href="">e-book version</a><br> <a href=""><img style="width: 30px;" src="" alt=""></a> <a href="">mobile version</a></p> </td> <td style="width: 30%;"> <p>Editor-in-Chief: <a href="" target="_self">Rubén A. Ananias</a><span id="result_box" class="short_text" lang="en"><br>Technical Editor</span>: <a href="">Linette Salvo S.<br></a>Digital Manager: <a href="">Victor Sepúlveda V.</a><br>E-mail :<a href=""></a><br>E-mail :<a href=""></a><br><br>2018 Journal Impact Factors:<br> 2-years: 1.4<br>5-years: 1.5<br> Frequency: 4 issues by year.<br>January, April, July, October<br>ISSN 0718-221X online version.<br>ISSN 0717-3644 printed version.</p> </td> </tr> </tbody> </table> Assessment of physical and mechanical properties of papua new guinea timber species 2019-09-02T11:31:21-04:00 Benoit Belleville Kilva Lancelot Elaine Galore Barbara Ozarska <p>A comprehensive testing program has been developed to assess different physical and mechanical properties of 26 commercial and lesser-known PNG species from secondary and plantation forests. The impact of log position in a tree on the mechanical properties has also been assessed to optimize the utilization of timbers along the value chain. The results showed that stiffness and bending strength tend to decrease or remain unchanged along the stem. Shear strength and Janka hardness displayed a similar trend to a lesser extent where the position in the tree had a limited impact on compression strength properties. Thus, segregating based on log position can be of interest where desired mechanical properties and costs associated with segregating justify optimum mechanical properties for the intended end use. The properties of selected species from plantations and regrowth forests were generally lower than those found in the literature for timbers from old-growth forests. The size of specimens tested, the amount and provenance of tested material, and some adaptive traits for tropical tree species are some factors potentially explaining observed differences. However, a comparison with recent studies tends to confirm the overall reduction of physical and mechanical properties when compared with old-growth forests timbers.</p> 2019-09-02T00:00:00-04:00 ##submission.copyrightStatement## The chemical and morphological properties of oleaster 2019-09-13T10:18:12-03:00 Mehmet Akgül Mehmet Akça <p>This study investigated the morphological characteristics and chemical properties of the wood and the chemical properties of the bark of the oleaster (<em>Elaeagnus angustifolia</em>) tree, which grows in a variety of climatic conditions in different regions of Turkey. The study materials were taken from three different regions of Turkey having different climatic conditions and elevations with the aim to determine the chemical properties of the bark and wood and the fiber properties of the wood. According to chemical analyses, no significant differences in the core components of the cell wall were observed between the heartwood and the sapwood. The samples collected from the Çankırı region had the highest holocellulose content (84.9%), while the proportions of alpha cellulose (52.3%) and lignin (24.0%) in samples taken from the Balikesir region were found to be higher than in samples from the other regions. According to the sugar analysis, glucose and xylose were found to be higher in the heartwood than in the sapwood. When the sugar ratios were evaluated by region, the glucose and xylose ratios were the highest in the Çankırı region (43.7% and 22.8%) and the lowest in the Konya region (38.3% and 20.5%). When looking at the inner bark (phloem) and outer bark (rhylidome) rates, the amounts of holocellulose and alpha cellulose were higher in the inner bark and the lignin rates were higher in the outer bark. The wood solubility values for cold and hot water, ethyl alcohol and the 1% NaOH were highest in samples from the Çankırı region and lowest in those from the Konya region, whereas bark solubility rates were highest in the samples taken from the Balıkesir region. When morphological characteristics were examined, no obvious differences were seen among the regions in terms of the fiber length, fiber width, lumen diameter or double wall thickness. Upon further investigation, it was determined that the oleaster tree wood was suitable for papermaking, but that the produced paper would exhibit a low resistance value because the average felting rate among the three growing regions was low (39.87%).</p> 2019-09-02T00:00:00-04:00 ##submission.copyrightStatement##