Search Results (46)

This research aimed to evaluate the biological resistance to xylophagous organisms and the dimensional stability related to water absorption in plastic wood panels manufactured by compression molding and produced with pine wood and recycled thermoplastics. The wood–plastic composites (WPCs) were prepared from 50% pine sawdust and 50% recycled plastics (polyethylene terephthalate-PET, high-density polyethylene-HDPE, and polypropylene-PP). The thickness swelling test was carried out by immersing of the WPC samples in water at room temperature (25–30 °C) and evaluating the total change in WPC thickness after 1500 h (≈9 weeks or two months). In addition, the coefficient of initial swelling was evaluated to verify the variability of the swelling. For the biological resistance evaluation of the WPCs, tests were carried out with soil or arboreal termites (Nasutitermes corniger) and drywood termites (Cryptotermes brevis). The WPC loss of mass and termite mortality were evaluated. The use of PP promoted the best response to thickness swelling. The simple mathematical model adopted offers real predictions to evaluate the thickness of the swelling of the compounds in a given time. For some variables there were no statistical differences. It was shown that treatment 3 (T3) presented visual damage values between 0.4 for drywood termites and 9.4 for soil termites, in addition to 26% termite mortality, represented by the lowest survival time of 12 days. The developed treatments have resistance to termite attacks; these properties can be an important starting point for its use on a larger scale by the panel industries. Full article

Acute oak decline (AOD) is a multifactorial disease that affects European oaks and represents a growing threat to forests. The disease results from a complex interaction between biotic and abiotic factors: the various environmental stresses, which vary depending on the area in question, and generally increased by climate change, predispose trees to attack by opportunistic pathogens. Among them, we focused on a bacterial consortium associated with AOD, consisting mainly of Brenneria goodwinii, Gibbsiella quercinecans, Rahnella victoriana, and Lonsdalea britannica, which produce degrading enzymes that contribute to phloem necrosis and the development of stem bleeds and bark cracks. However, the role of other pathogens, such as fungi, cannot be ruled out, but instead could be contributory. The potential involvement of xylophagous insects is also being studied, particularly Agrilus biguttatus, which, although, frequently associated with the disease, has not been conclusively demonstrated to act as an active vector of the bacteria. Currently, disease management requires integrated approaches, including monitoring and other forestry strategies to increase forest resilience. Given the phenomenon’s complexity and the risk of the future expansion of that bacterial consortium, further research is necessary to understand the dynamics and to develop effective containment strategies of AOD-associated bacteria. Full article

X-ray Computed Tomography (X-CT) is now an established technique for the investigation and diagnostics of Cultural Heritage. Its advantages include non-invasiveness, non-destructiveness, and the possibility of exploring the inner parts of an object without any modification. X-CT is often employed to investigate the construction methods of complex artifacts made with different parts or materials, but it is also able to support the analysis, intervention, monitoring and enhancement processes of artworks, creating digital models that can aid in the conservation and restoration procedures. In this work, several case studies are presented in which the CT technique has been decisive in identifying the effects of time and the events that occurred during the object’s life influencing its state of conservation. These range from large objects, such as an 18th century CE writing cabinet or an ancient Egyptian wooden coffin, to very small artifacts, like Mesopotamian lapis lazuli beads or fragments of Roman colored glass. Additionally, the results obtained by µ-CT investigations on the conservation state of a bronze arrowhead uncovered from the Urama-chausuyama mounded tomb (Japan, Kofun period, end of the 3rd century CE) are presented here for the first time. Lastly, the versatility of the technique when applied with different setups is highlighted. Full article

This study aimed to evaluate the influence of age on the colorimetric parameters, chemical composition, and biological resistance of teak heartwood, transition zone, and sapwood. Samples of 13- and 22-year-old trees were collected from fast-growing commercial plantations in Mato Grosso, Brazil. From the heartwood, transition zone, and sapwood sections, we determined the CIEL*a*b* system colorimetric parameters and extractive contents and performed Py-CG/MS analysis and an accelerated degradation assay with the xylophagous fungus Trametes versicolor (L.) Lloyd. The 22-year-old wood presented greater redness and lower yellowness, and the heartwood was darker, with greater redness and lower yellowness than the other radial positions. The average content of total extractives varied between ages: 7.83% (13years) and 8.23% (22years). A total of 119 compounds were identified in teak wood, of which 51 presented areas greater than 1%. Quinones were identified in the heartwood and transition zone, with similar values between ages and approximately 7% in the heartwood. Although the durability increased significantly with age, the magnitude was slight. Wood from 22-year-old trees exhibited a lower average mass loss (10.30%) compared to wood from 13-year-old trees (12.68%). In contrast, differences between regions were more pronounced. Sapwood showed a mass loss of 22.5%, transition zone wood of 10.14%, and heartwood of 1.86%. We concluded that age influenced the colorimetric parameters, chemical composition, and biological resistance of teak wood. Teak heartwood from fast-growing plantations, both from final harvesting (22-years-old) and from thinning (13-years-old), is indicated for uses that require high biological resistance. Full article

Wood quality has been an ongoing concern for science, having become increasingly important in the current context, in which the demand for wood is increasing and forest fires are more frequent and violent. This study aims to evaluate the quality of wood in trees affected by fires and the negative impact of these phenomena on the speed of wood degradation, as a result of weakening the trees due to the action of stress factors. The study was carried out using modern techniques on beech trees (Fagus sylvatica L.) remaining in an area affected by a litter fire in 2017. Measurements were taken with the Arbotom Rinntech sound tomograph, the IML Resi F-500S resist graph, and the Pressler core sampler to observe the quality of the wood inside the trees. It was found that all the trees were in various stages of decay, the tomograms being able to characterize the severity of decay only in the case of fully decayed wood as a result of the action of xylophages fungi, whose harmful influence is more pronounced when the injuries sustained by the trees are higher. Although the trees attempted to close the fire wounds through their own defense mechanisms, the destructive action of the fungi intensified with time. After the forest fires, for an effective assessment of the wood’s internal quality, the resist graph can be used. For valuable trees, one could use the tomograph, but the measurements have to be taken only by qualified operators. Full article

In this work, nanocellulose aqueous dispersions were studied as a bio-inspired consolidating agent for the recovery and conservation of ancient wood and compared with two of the most used traditional consolidants: the synthetic resins Paraloid B-72 and Regalrez 1126. The morphology of crystalline nanocellulose (CNC), determined using Scanning Electron Microscopy (SEM), presents with a rod-like shape, with a size ranging between 15 and 30 nm in width. Chemical characterization performed using the Fourier-Transform Infrared Spectroscopy (FT-IR) technique provides information on surface modifications, in this case, demonstrating the presence of only the characteristic peaks of nanocellulose. Moreover, conductometric, pH, and dry matter measurements were carried out, showing also in this case values perfectly conforming to what is found in the literature. The treated wood samples were observed under an optical microscope in reflected light and under a scanning electron microscope to determine, respectively, the damage caused by xylophages and the morphology of the treated surfaces. The images acquired show the greater similarity of the surfaces treated with nanocellulose to untreated wood, compared with other consolidating agents. Finally, a colorimetric analysis of these samples was also carried out before and after a first consolidation treatment, and after a second treatment carried out on the same samples three years later. The samples treated with CNC appeared very homogeneous and uniform, without alterations in their final color appearance, compared to other traditional synthetic products. Full article

Wood products used in outdoor applications can be degraded by xylophage organisms. For this reason, such products require treatments based on biocides in order to delay their service life. This brings troubles of its own due to the inherent toxicity of these treatments towards humans and the environment. Therefore, it is imperative to find less-toxic natural preservatives. In this context, this work deals with the evaluation of the fungitoxic effect of raw extracts obtained from three types of agroindustrial waste materials: bark of Quercus laeta spp., the cob of Zea mays, and the leaves of Agave tequilana Weber Blue variety. Extracts were incorporated into the test wood Alnus acuminata (Aile wood) via a full-cell process. Bark extracts provided excellent protection against the attack of Trametes versicolor (L. ex. Fr.) Pilát, improving the decay resistance of Aile wood from being nonresistant to resistant. Also, bark extracts from Q. laeta showed less leaching than the other extracts. Full article

Xylotrechus arvicola represents a significant insect pest impacting Vitis vinifera within the principal wine-producing territories of the Iberian Peninsula. The larvae of this species bore into grapevine wood, resulting in significant structural and biomechanical deterioration to the plant. Compressive and flexural tests were conducted to assess the mechanical properties of wood affected by X. arvicola. Compressive and flexural strength exhibited a decline with the escalation of the Total Damaged Surface Area (TDSA) of the samples, ranging from 0.31% to 0.73% in trunks and from 0.04 to 0.76% in branches, irrespective of the wood moisture content (fresh and dry). The most significant reduction in resistance occurred in affected dry trunks and branches. Notably, the deflection at break for dry samples was lower compared to fresh samples (65.00 and 97.85 mm, respectively). Moreover, the deflection at break for affected fresh samples (164.37 mm) significantly surpassed that of unaffected fresh samples (72.58 mm) and affected dry samples (37.50 mm). It is noteworthy that a higher percentage of TDSA coincided with diminished wood resistance. The percentage of fungal growth symptoms observed in affected wood samples was 66.66% for dry trunks, 75.00% for fresh branches, and 60.00% for dry branches. The damage inflicted by larvae facilitated the spread of grapevine diseases via emergence of holes created by insects upon exiting the wood and through the larval galleries connected to them. This damage also altered the mechanical properties of grapevine plants, with fresh branches exhibiting the most pronounced effects. Full article

Xylophagous insects play a crucial role in forest ecosystems, contributing to population dynamics. The “Cerambyx complex” (CC) constitutes an emerging pest in Mediterranean oak woodlands. We studied the fragmentation and connectivity of holm and cork oak stands in Andalusia (Spain), and the relationships with the current dispersion of CC, as well as the effect on the connectivity and dispersion patterns with the implementation of nests of a predator bird (Garrulus glandarius) to reduce insect populations in highly connected areas. The Kernel Density Estimation (KDE) was used to assess the spatial distribution of CC. Connectivity was assessed using graphs theory (Graphab 2.6) to characterize the importance of patches and linkages for contributing to dispersal. We selected the Eurasian jay (G. glandarius) as a reference bird species to generate “barriers” to the dispersion of the CC. We used the probability of connectivity (PC) and the flux (F) to compare the effect of the introduction of Eurasian jay nets. Results showed an increasing trend in the distribution and incidence of CC during the period 2001–2016, resulting in 7.3% and 13.1% mortality rates for Q. ilex and Q. suber, respectively. The connectivity model using only Q. ilex and Q. suber forests as reference habitats was not enough to explain the distribution of CC. The value of PC and F metrics decreased by 38.09% and 20.59% by introducing 300 nests of Eurasian jay. Our methodology provides a pest management tool using connectivity metrics, which can be integrated with other variables to control pest outbreaks and pest dispersion. Full article

Xylophagous fungi are able to thrive inside wood because they produce enzymes that can degrade it and cause significant damage. Due to this process, in the case of wood that forms part of the structure of a building or furniture, xylophagous fungi pose a serious problem that needs to be addressed, as they can compromise the integrity and durability of the wood. The aim of this work was to obtain extractives from Cedrela fissilis wood in order to conduct a preliminary evaluation of their antifungal activity against xylophagous fungi Trametes trogii (white rot), Pycnoporus sanguineus (white rot), and Chaetomium globosum (soft rot). The antifungal activity of the extractives was evaluated against these xylophagous fungi through tests of growth fungal colonies with the extractives in Petri dishes. All the evaluated extractives showed antifungal activity against all the fungi tested, demonstrating their potential use as natural biocides for wood artwork of Cultural Heritage. Full article

The wood borer Cerambyx welensii Küster is a key contributor to Quercus open woodland (dehesa) decline. Among other factors, olfactory and visual cues could influence host colonisation by this species. In this study, we investigated whether the physiological performance and morphological features of Q. suber trees under summer stress are affected by C. welensii infestation. Additionally, we analysed the relation between morpho-physiological variables and the emission of monoterpenes that potentially mediate host selection by C. welensii. Thirty-six Q. suber trees with known monoterpene emission profiles were selected: 18 trees highly visited by C. welensii, and 18 neighbouring trees not visited or at least not visibly damaged by this wood borer. For each tree, we assessed photosynthesis, stomatal conductance, and transpiration during the early evening, and also the perimeter and crown projection. Trees visited by C. welensii maintained higher photosynthetic activity than non-visited trees (1.5–2.15 times) from 19:35 to 20:45 h. Visited trees had larger perimeters and smaller crown projection area-to-perimeter ratios than non-visited trees. Results suggest that, under stress conditions, the physiological performance of trees infested by C. welensii could have favoured foliar emission of certain monoterpenes influencing intraspecific host selection by this species. Full article

This study focuses on Populus ×euramericana (Dode) Guinier, a globally distributed fast-growing tree. Despite its valuable wood, it exhibits low durability. The aim of this study was to assess the efficacy of a binary composite comprising silver nanoparticles (AgNPs) and chitosan oligomers (COS) in protecting P. ×euramericana ‘I-214’ wood against degradation caused by xylophagous fungi and termites through vacuum-pressure impregnation. The test material was carefully selected and conditioned following the guidelines of EN 350:2016, and impregnation was carried out in accordance with EN 113-1:2021. Five concentrations of AgNPs–COS composites were utilized. Biodeterioration resistance was evaluated based on EN 350:2016 for white (Trametes versicolor (L.) Lloyd) and brown (Coniophora puteana (Schumach.) P.Karst.) rot fungi, and EN 117:2012 for subterranean termites (Reticulitermis grassei Clément). The durability class and use class were assigned following EN 350:2016 and EN 335:2013, respectively. In comparison to the untreated control, the binary solution at its highest concentration (AgNPs 4 ppm + COS 20 g·L⁻¹) demonstrated a notable reduction in weight loss, decreasing from 41.96 ± 4.49% to 30.15 ± 3.08% for white-rot fungi and from 41.93 ± 4.33% to 27.22 ± 0.66% for brown rot fungi. Furthermore, the observed termite infestation shifted from “heavy” to “attempted attack”, resulting in a decrease in the survival rate from 53.98 ± 10.40% to 26.62 ± 8.63%. Consequently, the durability classification of P. ×euramericana I-214 witnessed an enhancement from “Not durable” to “Slightly” and “Moderately durable” concerning decay fungi and termites, respectively. These findings expand the potential applications of this wood and substantiate the advantages of employing this environmentally friendly treatment. Full article

The black weevil Aclees taiwanensis Kôno, 1933 (Coleoptera: Curculionidae) is a xylophagous insect native to Southeast Asia and introduced to Italy in 2005. Here, the species completes its entire life cycle on Ficus carica L., causing economic damage and leading to the plants’ death. Nowadays, there are no insecticides registered for its control. In this study, a commercial product based on Beauveria bassiana, Naturalis^®, was associated with Rincotrap^® tissue. Semi-field trials were carried out on fig seedlings by comparing two different concentrations (3% and 10%) of this entomopathogenic fungus distributed in suspension on Rincotrap^® bands. The results showed that the fungal product had a biocidal effect in both treatments. Afterward, trials were conducted in a fig orchard in order to verify the effectiveness of this association in the field. The addition of Naturalis^® at a 3% concentration to Rincotrap^® bands did not alter the number of adults captured. The total mortality was 43.7% and 23.8%, respectively, in the treated and control plots. Among the total number of dead adults, only the mortality rates of B. bassiana exceeded 70% in both plots. Further long-term studies in several environments are necessary to improve this technique and create an integrated control system for the black fig weevil. Full article

Heritage objects with wooden supports can degrade in inappropriate storage conditions or when microclimate factors contribute to the development of biological attacks. Another issue regarding the deterioration of artifacts is the lack of a full understanding of material properties and their behavior during restoration treatments. In this paper, we note the strengthening treatments of artifacts with severely damaged wood and the various treatments against bio-pests. The influence of solvent on dimensional changes was observed for water, acetone, and white spirit. Acetone was found to cause the greatest swelling and deformation of the treated panels. The present work highlights the importance of choosing not only the correct types of solvents for the solubilization of synthetic resins, as well as those used in conservation-restoration treatments, but also the effects they have on polychrome wood panels that have been degraded by xylophagous insects. Full article

The organic nature of wood makes it susceptible to abiotic and biotic degradation. Impregnation with chemical products is the most common method of protection. Only inorganic borates combine the unique set of properties that make them well suited for wood protection: they are insecticidal, fungicidal and flame retardants. In this work, zinc borate is suspended in an ammonia solution and applied in depth to wood. Its resistance to leaching is evaluated. The product is tested against rot fungi (Gloeophyllum trabeum and Trametes versicolor) and a xylophagous insect (Anobium punctatum). The results verify its effectiveness as a wood protector, while leaching less than other borate-based products. Full article