Search Results (17)

A study was conducted to improve the effectiveness of silvicultural production of structural sawn timber from softwoods. It intends to explore prediction methods for mechanical timber quality. The study material was obtained from six stands divided into age groups of approximately 40- and 80-year-old trees (examining the influence of age). The stands were differentiated by their applied thinning system of thinning from below or above (examining the influence of the thinning system). Resulting from these different levels of data, i.e., stand parameters, tree anatomy, and visual board properties are examined and analyzed in ordinal logistic models and linear mixed models. Visual board properties were discerned by means of the German standard for visual grading of sawn timber. The mechanical board properties were measured in on-edge bending strength tests and allocated into strength classes, which were modeled in dependence of visual characteristics and forestry conditions. The evaluation of mechanical properties attributed a significant loss of timber quality to short rotation periods, non-ideal water supply, and a single-tree management system. The prediction capabilities of models based on site and tree characteristics were on par with the accuracy of visual grading. Management adaptations by intense thinning from above can lead to a significant decline in Norway spruce (Picea abies L.) timber quality when site factors coincide. Particular care should be taken in the management of locations with high yield potential. Non-destructive evaluation based on site characteristics combined with terrestrial laser scan data of tree characteristics has potential as a pregrading method. Full article

This study takes the wooden components of the different parts of the ancient buildings at the site of the Zhuangzishang Conference as the object of study, and investigates the deterioration state of the different wood components. To assess their degree of degradation, the wood anatomy, basic density (BD), maximum water content (MWC), cell wall major components, X-ray diffraction (XRD), infrared spectroscopy (IR), and thermogravimetry (TG) were used to compare the samples of new and old wood from the same species. The window (W) was identified by microscopic characterization as cypress (Cupressus sp.), the footing beam (FB) and the weatherboard (WB) as pine (Pinus spp.), the purlin (P) and the column (C) as Chinses fir (Cunninghamia spp.), and the floor (F) as spruce (Picea sp.). In terms of their physical properties, the old wood had a lower basic density of 2.58%–38.19%, a lower air-dry density of 2.87%–39.81%, and a higher maximum moisture content of 8.52%–41.38% compared to the reference wood. The degradation of the FB, which has been subjected to moisture and sunlight, and the P, which has been subjected to termite damage, was greater than that of their conspecifics. The integrated holocellulose of the ancient wood was 3.34%–16.48% less, and the hemicellulose was 1.6%–21.92% less compared to that of the reference wood, and the lignin was 1.32%–25.07% more. The XRD results showed that the crystallinity of the cellulose was greater in the different species of ancient wood compared to the control wood, which was caused by the decrease in the amorphous zones of the hemicellulose and cellulose in the ancient wood. The IR indicated that the degradation of cellulose and hemicellulose occurred in the old wood of all species, from the new lignin uptake peaks in the UV-exposed W, FB, and WB compared to the control timber. The pyrolytic behavior of the ancient and control timber is mainly related to the degradation of the tree species and the ancient wood holocellulose. These results show that the differences in the wooden components of the different parts of the ancient buildings at the Zhuangzishang Conference site are mainly related to the species of trees used in the components, and are secondly related to the location of the ancient wood members, which provides useful information for the protection and repair of the ancient buildings at the site. Full article

Timber, the most prevalent organic material on this planet, is the result of a secondary xylem emerging from vascular cambium. Yet, the intricate processes governing its seasonal generation are largely a mystery. To better understand the cyclic growth of vascular tissues in elm, we undertook an extensive study examining the anatomy, physiology, and genetic expressions in Ulmus pumila. We chose three robust 15-year-old elm trees for our study. The cultivars used in this study were collected from the Inner Mongolia Autonomous Region in China and nurtured in the tree farm of Shandong Normal University. Monthly samples of 2-year-old elm branches were taken from the tree from February to September. Marked seasonal shifts in elm branch vascular tissues were observed by phenotypic observation: In February, the cambium of the branch emerged from dormancy, spurring growth. By May, elms began generating secondary xylem, or latewood, recognized by its tiny pores and dense cell structure. From June to August, there was a marked increase in the thickness of the secondary xylem. Transcriptome sequencing provides a potential molecular mechanism for the thickening of elm branches and their response to stress. In February, the tree enhanced its genetic responses to cold and drought stress. The amplified expression of CDKB, CYCB, WOX4, and ARF5 in the months of February and March reinforced their essential role in the development of the vascular cambium in elm. Starting in May, the elm deployed carbohydrates as a carbon resource to synthesize the abundant cellulose and lignin necessary for the formation of the secondary wall. Major genes participating in cellulose (SUC and CESA homologs), xylan (UGD, UXS, IRX9, IRX10, and IRX14), and lignin (PAL, C4H, 4CL, HCT, C3H, COMT, and CAD) biosynthetic pathways for secondary wall formation were up-regulated by May or/and June. In conclusion, our findings provided a foundation for an in-depth exploration of the molecular processes dictating the seasonal growth of elm timber. Full article

The vascular cambium is an extensive and permanent secondary meristem with wood cells products of periclinal divisions commonly contributed to two directions and arranged in radial files of trees. Cambium activity is the origin of timber production. Taxodium ascendens Brongn is an exotic species in China, and its apical meristem and cambial activity are still elusive, resulting in a lack of understanding about its wood formation and improvement. We thus addressed this knowledge gap by studying Cambium activity. For studying, twigs from five 30-year-old healthy trees were collected between February-2017 and March-2018. Anatomy deciphered its apical meristem with a Cryptomeria–Abies type. The procambium appeared after leaf primordium and initially presented five lobes as observed transversely from a one-year-old shoot. The procambium under the apical differentiated into protophloem first and then protoxylem toward the inside. It means that protoxylem differentiated later than protophloem did. After dormancy, the vascular cambium began to be active, starting in early April 2017, which was later than shoot differentiation. On 25 July 2017, the cambial zone had 9–10 immature xylem cell layers. Both initiation and cessation of the xylem preceded that of the phloem. Until 10 October 2017, few immature elements were found, indicating the translation of cells from activity to dormancy. On 15 November 2017, the cambium contained 3–4 cells in radial rows, which demonstrated the dormancy of the cambium until next spring. Furthermore, immature xylem elements increased as cell layers in the cambium zone and cell fission increased. The growth pattern of T. ascendens revealed that cambial activity is highly seasonal and dependent on changes in abiotic conditions. Thus, the wood formation in the species will be significantly altered in a changing climatic pattern. These enhance our understanding of tree growth science, wood formation, wood structure, wood properties variation and wood improvement in tree breeding. Full article

Traditional architecture characteristically uses locally available materials to develop constructive systems and techniques, providing an optimum response to the needs of the population. This study focuses on half-timber walls as a traditional technique taking material form in a wide range of variants found mostly in the northwest half of Spain. Primarily aiming to ensure the broad objective of in-depth documentation, understanding, and study, the microscopic analysis of 24 timber samples obtained from different half-timber walls is proposed. This analysis aims to identify the species or species groups used and to establish a correlation with different aspects of construction including structural resistance, durability, and workability. This makes it possible to identify the predominant use of species found close to the locations from which the samples are obtained, using relatively resistant species for the structural elements of the half-timber wall, as well as the use of species with flexible and easily malleable branches for the construction of the enclosure panels. This indicates that, among the species available in a given location, builders have a degree of knowledge on the characteristics of the material, so they could choose the most suitable ones or develop specific constructive solutions based on these characteristics. Full article

The increasing demand for precious timber resources promotes immediate efforts to develop high-valuable hardwood resources in afforestation. However, the lack of valuable tree species seedlings for afforestation and their ecological adaptability must primarily be addressed. To explore a valuable tree species for precious timber resourcing in afforestation, a comparative analysis of the characteristics of photosynthetic physiology and leaf anatomy in three different Quercus L. Section Cyclobalanopsis seedlings of Quercus chungii, Quercus gilva, and Quercus glauca was performed during three growth stages (July, September, and November) in South China. The results showed that there are significant differences in photosynthetic physiological characteristic parameters, chlorophyll content, and leaf anatomical structure among the three seedlings in each growth stage (p < 0.05). The photosynthetic parameters, i.e., Pn, Gs, Tr, WUE and Ci in each tree species all had the same trend of increase from July to September and decrease from September to November, and with a pick point in September during the three stages. The Pn in Q. chungii was higher than that in the other two species in each stage, and the highest Pn with an average value of 8.26 μmol·m⁻²·s⁻¹ was obtained in September in Q. chungii, which was 13.77% and 20.06% higher than that of in Q. gilva and Q. glauca at the same time, respectively. Significant differences were also detected in the chlorophyll fluorescence of Fo, Fm, Fv/Fm, Y, ETR, qP, and NPQ among three seedlings within each growth stage from July to November (p < 0.05). The thickness of the mature leaf was decreased in order as Q. chungii, Q. glauca, and Q. gilva. From July to September, more notable changes were observed in Q. chungii in September, with a drop of 3.49% in leaf thickness, and a drop of 3.34% and 10.06% in the volume of palisade tissue and sponge tissue, respectively. Consequently, increasing tightness and deducing looseness were observed in Q. chungii. The principal component analysis (PCA) on photosynthesis and leaf anatomy showed that Q. chungii displayed a stronger photosynthetic physiology with a positive coordination on water, air, light, and heat. These findings facilitate the evaluation of ecological adaptability among the three Quercus seedlings and provide compelling evidence for the application of Q. chungii for precious timber resources in afforestation. Full article

Tropical species are highly valued timber sources showing a large diversity of wood characteristics. Since there are major concerns regarding the sustainability of these tropical species in many tropical regions, knowledge of the variability in wood properties is therefore a valuable tool to design targeted exploitation and to enlarge the wood resources base, namely by identifying alternatives for CITES-listed species. In this study, 98 tropical wood species belonging to 73 genera from India, Mozambique, and East Timor were investigated regarding wood anatomy and physical properties. Numerical taxonomy, by means of cluster analysis and principal component analysis grouped species with anatomical and physical similarities from different geographical origins. In addition to wood density, ray and vessel characteristics as well as wood moisture and wood shrinkage properties explained the main variability of these species. The contribution of wood color patterns was highlighted as consistently separating the Mozambique woods. A distinct geographical pattern was not observed, reinforcing that species from India, Mozambique, and East Timor show similar anatomical and physical wood properties, which could be useful to increase timber trade diversity. The multivariate analysis showed that species from Mozambique, such as Morus mesozygia, and Millettia stuhlmannii and Swartzia madagascariensis, could be alternatives for the CITES-listed species Cedrela odorata and Dalbergia melanoxylon, respectively. Full article

(1) Background: Pinus heldreichii is a long-living tree subalpine species commonly used for climate reconstruction. Nevertheless, its potential for dendroarchaeology and dating of historical timber remains unknown. In Metsovo and in the surrounding area of Pindus National Park (Northern Greece) it is commonly used for the construction of buildings and wooden objects and artifacts. (2) Methods: We examined timber found in historical buildings within the study area and we tried to date it using local reference chronologies of Bosnian and Black pines. (3) Results: Bosnian pine chronologies can be used to date timber from historical buildings, while they can also be used as reference chronologies against Black pines, giving very high cross-dating values. Therefore, and since the macroscopic identification of the two species’ timber is impossible, the analysis of wood anatomy is necessary to distinguish the two species in the case of historical wood. (4) Conclusions: The current paper presents the first application of dendroarchaeology for Bosnian pine and highlights the potential of the species in studying cultural heritage and the human past. Full article

Tannin polyphenols are produced by plants to protect themselves against natural decay. It is expected that impregnating low-durable timber with tannin extracts of more durable species such as quebracho (Schinopsis balansae) will enhance the durability of the specimens. This biomimetic approach combined with the in situ polymerization of quebracho–hexamine formulations can be a valid alternative to synthetic wood preservatives. In this work, we aim to evaluate the impregnation mechanism as well as the impact of tannin and hardener concentration on the mechanical and leaching resistance properties of treated wood. Compression resistance, surface hardness and leaching resistance of four different common non-durable wood species: spruce (Picea abies), pine (Pinus spp.), poplar (Populus alba) and beech (Fagus sylvatica) impregnated with different concentrations of extract and hexamine are presented. The results show that the mechanical properties of tannin-impregnated timber are enhanced, especially for timber with lower densities. Tannin and hardener concentrations tendentially do not contribute significantly to further increase MOE (modulus of elasticity), MOR (modulus of rupture) and Brinell hardness. Similar results are also obtained when the specimens are tested against leaching: tannin is significantly more water-resistant when cured with hexamine, but higher amounts of hardener do not further improve its water resistance. These findings suggest that quebracho tannin–hexamine formulations are already effective at low concentrations (5 to 10% extract with 2.5 to 5% hexamine). Full article

The antimicrobial characteristics of Australian commercial timber species were studied using a direct screening method and two different microorganisms. The effectiveness of timber samples was compared with plastic and paper samples during an incubation period of 24 h at 37 °C. The initial data with E. coli and S. aureus showed no difference in performance between the plastic and paper samples and the softwood samples tested. Hardwood samples, however, showed an inhibition zone when tested with S. Aureus. The data showed similar trends of inhibition zones developed for sterilised and non-sterilised samples of spotted gum and shining gum species. The observed data showed promising antimicrobial characteristics for both veneer and solid samples of hardwood species. Further studies investigating the type of extractives, their role in antimicrobial characteristics and differences in the type of surface exposed to the microbial contamination from the point of view of timber’s anatomical properties are proposed. Full article

Climate change will affect radial growth patterns of trees, which will result in different forest productivity, wood properties, and timber quality. While many studies have been published on xylem phenology and anatomy lately, little is known about the phenology of earlywood and latewood formation, also in relation to cambial phenology. Even less information is available for phloem. Here, we examined year-to-year variability of the transition dates from earlywood to latewood and from early phloem to late phloem in Norway spruce (Picea abies) from three temperate sites, two in Slovenia and one in the Czech Republic. Data on xylem and phloem formation were collected during 2009–2011. Sensitivity analysis was performed to determine the specific contribution of growth rate and duration on wood and phloem production, separately for early and late formed parts. We found significant differences in the transition date from earlywood to latewood between the selected sites, but not between growth seasons in trees from the same site. It occurred in the first week of July at PAN and MEN and more than two weeks later at RAJ. The duration of earlywood formation was longer than that of latewood formation; from 31.4 days at PAN to 61.3 days at RAJ. In phloem, we found differences in transition date from early phloem to late phloem also between the analysed growth seasons; from 2.5 weeks at PAN to 4 weeks at RAJ Compared to the transition from earlywood to latewood the transition from early phloem to late phloem occurred 25–64 days earlier. There was no significant relationship between the onset of cambial cell production and the transition dates. The findings are important to better understand the inter-annual variability of these phenological events in spruce from three contrasting temperate sites, and how it is reflected in xylem and phloem anatomy. Full article

The cypress (Cupressus sempervirens) is characterized by a very ancient history linked to the wide employment for the technological properties of its wood and for its symbolic value. Although this tree was often considered as a species introduced in Italy, the first genetic studies showed, instead, the presence of an autochthonous population of C. sempervirens in the forest of Fontegreca (Matese massif, Southern Italy), which constitutes the unique autochthonous cypress woodland present in Southwestern and Western Europe. Therefore, investigations were carried out in selected (using geomorphological criteria) areas of the forest, through soil chemical analysis, identification and ¹⁴C dating of soil charcoals. Indeed, we hypothesize that these analyses allow clarifying the history of this woodland characterized by the dominance of the cypress in the forest cover. Areas at medium-low (17–29°) slope gradient on the eastern and southern slopes of the forest were investigated and sampled, following pedological criteria (soil horizons order). Soil morphological and chemical analysis showed humus-rich surface horizons, thin (15–30 cm) and poorly developed (young) soils, overlapping the bedrock limestones. The first soil charcoal analysis data highlighted the presence of a previous landscape characterized by several species (e.g., Pistacia, Ostrya carpinifolia, Juniperus sp. and Pinus sp.) and, probably, by a different forest structure. Ongoing charcoal identification and ¹⁴C dating will likely give a better understanding of both (1) the cypress history and (2) the development of this forest landscape. Full article

When assessing the hygrothermal performance of timber windows, it is important to apply the unique thermal conductivity of wood by each wood species as well as an anatomical direction within the same material as they affect the performance and long-term durability of products. A series of heat transfer analyses of window frames using THERM and WINDOW along with measurements on the thermal conductivity of five hardwoods using laser flash apparatus (LFA) was performed to compare and evaluate heat transmittance (U-value) and condensation resistance (CR) of three types of timber and hybrid timber windows. For each window type, 6.1 to 10.3% of the maximum difference in the heat transmittance among cases was calculated. Besides, a linear correlation was found between the U-value and the CR for most cases; thus, the selection of wood species and anatomical direction would improve the hygrothermal performance of timber windows overall. The results also indicated that there were some cases where the overall CR of windows did not improve because the U-value of the glazing system was not sufficiently low. Full article

Wood anatomy is a key discipline as a tool for monitoring the global timber trade, particularly for wood listed in protected species conventions such as Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). One of the main barriers to reducing illegal trafficking of protected species is ensuring that customs officials with appropriate training in wood anatomy are equipped with simple tools, at both the origin and destination of shipments, so they can raise an early warning about wood suspected of contravening international treaties and immediately send samples to a specialised laboratory. This work explains how lenses attached to a smartphone, capable of achieving up to 400× magnification using the phone digital zoom, can be used to distinguish features that are not visible with traditional 10× or 12× lenses, enhancing the capacity to view features not typically observable in the field. In softwoods, for example, this method permits determination of the type of axial parenchyma arrangement, whether there are helical thickenings in axial tracheids and whether axial tracheids have organic deposits or contain alternate polygonal pits, and in the rays, if the tracheids are smooth-walled or dentate and if the cross-field pits are window-like. In hardwoods, it allows verification of the presence of tyloses and deposits in vessels, the type of perforation plates and whether the intervascular pitting is scalariform; in the rays it is possible to differentiate the types of ray cells; and in the axial parenchyma, to determine the presence of oil cells. In addition, unlike macroscopic analysis with a conventional magnifying lens, this type of lens can be used with the appropriate mobile application for the biometry of important elements such as ray height and vessel diameter. Full article

Research Highlights: Tree size and wood characteristics influenced the susceptibility of five Amazonian timber tree species to heartwood decay and colonization by termites. Termites occurred in the heartwoods of 43% of the trees, with Coptotermes testaceus the most abundant species. Background and Objectives: Hollows and rotten cores in the stems of living trees have ecological and economic impacts in forests managed for timber. The decision on whether to cut or maintain hollow trees in such forests must account for the susceptibility of different tree species to decay. We investigated tree and wood characteristics of living trees of five commercial timber species in the eastern Amazon that influenced the likelihood of heartwood decay and the occurrence of termite nests inside the rotten cores. Materials and Methods: We used Pearson’s correlations and one-way analysis of variance (ANOVA) to explore relationships among tree basal area and hollow area. We used principal components analysis (PCA) to analyze the variation of wood anatomical traits, followed by a linear regression to explore the relationships between PCA scores, and heartwood hollow area. We used a logistic model to investigate if the probability the occurrence of colonies of C. testaceus inside tree cores varied with tree and species characteristics. Results: Heartwood hollow areas increased with stem basal area. Larger hollows were more likely to occur in species with higher vessel and ray densities, and smaller diameter vessels. Termites occurred in the hollows of 43% of the trees sampled, with C. testaceus the most common (76%). The probability of encountering termite nests of C. testaceus varied among tree species and was positively related to wood density. Conclusions: This study shows that given the increased likelihood of stem hollows and rotten cores in large trees, tree selection criteria in managed tropical forests should include maximum cutting sizes that vary with the susceptibility of different tree species to stem decay. Full article