Natural Durability Of Wood Research Articles

Development of extraction methodology for identification of extractive-compounds indexing natural durability of selected wood species

ABSTRACT This study is concerned with establishing a uniform experimental protocol for the determination of phenolic extractives, which play an essential role in the durability of the wood of selected species included in the field tests. European larch (Larix decidua), Norway spruce (Picea abies), Scots pine (Pinus sylvestris), European oak (Quercus sp.), sweet chestnut (Castanea sativa), and black locust (Robinia pseudoacacia) were included in the study. Extraction yield data were collected for extraction in a Soxhlet apparatus using common polar extraction solvents (ethanol, acetone, methanol, water) and for single static extraction cycles in accelerated solvent extraction (ASE). The suitability of the solvents and the appropriate extraction conditions were evaluated based on the results of gravimetric analysis of hydrophilic extractives, spectrophotometric analysis of total phenols, and chromatographic analysis using high-performance liquid chromatography. Extraction in the ASE system with methanol proved to be a quick and accurate way to prepare samples for chemical analysis of extractives of selected wood species. With the chemical monitoring of targeted phenolic extractives in wood subjected to leaching, we propose a novel protocol suitable also for for measuring the effects of weathering on the natural durability of wood in future studies.

Biological Deterioration and Natural Durability of Wood in Europe

In recent years, the use of wood has gained social interest, leading to a global increase in its demand. Yet, this demand is often covered by the production of woods of low natural durability against biological deterioration. The main biological agents with the potential to attack the structural integrity of wood are wood-decay fungi, saproxylic beetles, termites, and marine molluscs and crustaceans. In most circumstances, fungi are the main wood-deteriorating agents. To attack the cell wall, wood-decay fungi combine a complex enzymatic mechanism with non-enzymatic mechanisms based on low-molecular-weight compounds. In some cases, the larvae of saproxylic beetles can also digest cell wood components, causing serious deterioration to wooden structures. The impact of subterranean termites in Europe is concentrated in the Southern countries, causing important economic losses. However, alien invasive species of voracious subterranean termites are expanding their presence in Europe. Wooden elements in permanent contact with marine water can be readily deteriorated by mollusc and crustacean borers, for which current preservatives lack efficacy. The natural durability of wood is defined as the inherent resistance of wood to catastrophic action by wood-destroying organisms. Besides exposure to the climate, product design and use conditions, the natural durability of wood is key to the prediction of the service life of wooden products, which can be shortened due to the impact of global change. The major wood properties involved in natural durability are related to the composition of lignin in the cell wall, the anatomy of the xylem, nutrient availability, the amount and composition of heartwood extractives, and the presence of moisture-regulating components since wood moisture content influences the establishment of wood-degrading organisms.

KETAHANAN ALAMI KAYU HIBRID AKASIA (Acacia mangium × A. auriculiformis) TERHADAP SERANGAN RAYAP KAYU KERING (Cryptotermes cynocephalus Light.)

Development of Acacia hybrid is important to be done due to their superiority such as high productivity, good wood quality, more tolerance to pest/disease and adaptive to marginal sites, although its wood durability to wood-destroyer organism attacks is still unknown yet. This study aimed to observe the wood natural durability of Acacia hybrid to drywood termites (Cryptotermes cynocephalus Light.) attack. The wood samples used were taken from 6 years old trees of Acacia hybrid in Wonogiri, Central Java. The experimental design used is completely randomized design using two factors, axial and radial of wood section with the number of trees as replication.Parameters measured were extractive content, termite mortality and wood mass loss.The results showed that the axial section of wood significantly affected the wood extractive content at the level of 0.01, while termite mortality and the mass loss of wood were not significantly affected by the wood section. The largest average percentages of termite mortality and mass loss of wood found on the middle of wood section (96.67%) and near the bark (1.14%) respectively. Based on this result, the Acacia hybrid wood is categorized as very durable wood and potential to be developed as raw material for solid wood-based industries

PENGARUH LAMA PENGUJIAN TERHADAP SERANGAN PENGGEREK KAYU DI LAUT PADA KAYU MALAPOGA (Toona ciliata) DAN KAYU TEA (Artocarpus elasticus Reinw. Ex Blume)

Timber in brackish waters and at sea is often damaged by marine wood borer (marine borers). For some fishing communities and people living in coastal areas, the use of boats is very important for them as a support for their livelihood as a means of transportation. Until now, the use of wood as raw material for boats is still frequently used. The wood used in boat building will of course often come in contact with sea water so that it does not rule out the attack of marine borers that will reduce the strength of the wood especially if it is used for a long time. The research objective was to determine the effect of the length of testing at sea on the strength (MOE and MOR) and the natural durability of Malapoga wood (Toona ciliata) and Tea wood (Artocarpus elasticus Reinw. Ex Blume). This research was conducted for 3 months at the Material Testing Laboratory, Faculty of Engineering and Agrotechnology Laboratory, Faculty of Agriculture, Tadulako University, while testing for marine borers was carried out in the waters of Talise Village, East Palu District, Palu City, Central Sulawesi. The test uses the Malapoga wood and Tea wood test samples with sizes2 cm x 2 cm x 30 cm. Meanwhile, at sea testing and data analysis using a completely randomized design (CRD) factorial pattern with 2 factors was repeated 5 times so that there were 30 samples with 10 test samples (control) without immersion in the sea. The results showed that the length of the test had a very significant effect on the strength of wood (MOE and MOR) and the natural durability of wood (weight loss percentage) and the types of Malapoga wood and Tea wood were classified in the strong class V (five).

Comparison of natural durability of wood by stake tests followed by survival analysis

The conventional stake test is widely used to evaluate wood durability. The test monitors the deterioration level observed on stakes partially inserted into the ground. The test results are conventionally expressed as the relationship between the mean deterioration level and exposure periods. Durability is compared between the stake groups based on the test results; however, there is no scientific basis for the comparison. To include a scientific basis to the conventional stake test, we applied survival analysis to it. Four stake groups were subjected to deterioration at three sites for 7 years. The deterioration levels were monitored according to the conventional procedure, and survival analysis was applied to the monitored data. The Kaplan–Meier curves plotting the survival probabilities against the exposure periods indicated that the durability of the test stakes of Japanese cedar heartwood is higher than those of Japanese cedar sapwood. However, it was also demonstrated that the durability ratio between Japanese cedar heartwood and sapwood was strongly dependent on the test sites. It was also revealed that the durability of the heartwood portion did not differ significantly among Japanese cedar, Japanese cypress, and Japanese larch. These results were verified using the modified Gehan–Wilcoxon test.

A reverse chemical ecology approach to explore wood natural durability.

SummaryThe natural durability of wood species, defined as their inherent resistance to wood‐destroying agents, is a complex phenomenon depending on many biotic and abiotic factors. Besides the presence of recalcitrant polymers, the presence of compounds with antimicrobial properties is known to be important to explain wood durability. Based on the advancement in our understanding of fungal detoxification systems, a reverse chemical ecology approach was proposed to explore wood natural durability using fungal glutathione transferases. A set of six glutathione transferases from the white‐rot Trametes versicolor were used as targets to test wood extracts from seventeen French Guiana neotropical species. Fluorescent thermal shift assays quantified interactions between fungal glutathione transferases and these extracts. From these data, a model combining this approach and wood density significantly predicts the wood natural durability of the species tested previously using long‐term soil bed tests. Overall, our findings confirm that detoxification systems could be used to explore the chemical environment encountered by wood‐decaying fungi and also wood natural durability.

Natural durability of four TunisianEucalyptusspp. and their respective compositions in extractives

AbstractEucalyptustrees have been adapted to the Tunisian climate. Now, they need to be economically valued. TunisianEucalyptushave great technological properties allowing us to use them as wooden material. However, there is large variability in the natural durability between heartwoodEucalyptusspp. The wood sustainability assessment provides reliable parameters to predict the service life of wood-based products. This study aimed to evaluate the wood deterioration of four North Tunisian fast-growingEucalyptusspp. (Eucalyptus maidenii,Eucalyptus saligna,Eucalyptus camaldulensisandEucalyptus gomphocephala) exposed to basidiomycetes (Coniophora puteanaandTrametes versicolor) and termite (Reticulitermes flavipes) attacks. Among the fourEucalyptuswoods,Eucalyptus gomphocephalapresents the highest decay and termite resistance. The fourEucalyptuswood species are classified as very durable against fungal degradation and durable against termite attacks, expect forEucalyptus salignawhich is classified as sensible against termites. The natural durability ofEucalyptusseems to be mainly caused by extractives, and a lot of compounds are involved. Antifungal and anti-termite properties of these compounds were put in perspective with the natural durability of wood. Gas chromatography-mass spectrometry (GC-MS) analyses highlighted thatEucalyptusdurability is mostly governed by gallic acid, fatty acid glycerides, fatty acid esters, phenolic compounds, sitosterol, catechin and ellagic acid.

Fungal Glutathione Transferases as Tools to Explore the Chemical Diversity of Amazonian Wood Extractives

The natural durability of wood is linked to its chemical composition and in particular the presence of metabolites called extractives that often possess chemical reactivity. For dealing with these compounds, wood degraders have developed detoxification systems usually involving enzyme families. Among these enzymes, glutathione transferases (GSTs) are involved in the decrease of the reactivity of toxic compounds. In this study, the hypothesis that the detoxification systems of wood decaying fungi could be indicators of the chemical reactivity of wood extracts has been tested. This approach has been evaluated using 32 wood extracts coming from French Guiana species, testing their antimicrobial ability, antioxidative properties, and reactivity against six GSTs from the white rot Trametes versicolor. From the obtained data, a significant correlation between the antimicrobial and antioxidative properties of the tested wood extracts and GST interactions was established. In addition, the chemical analysis performed on one of the most reactive extracts (an acetonic extract of Bagassa guianensis) has demonstrated oxyresveratrol as a major constituent. We were able to cocrystallize one GST with this commercially interesting compound. Taken together, the presented data support the hypothesis that detoxifying enzymes could be used to identify the presence of molecules of industrial interest in wood extracts.

SELECTION OF PLUS TREES FOR GENETICALLY IMPROVED TEAK VARIETIES PRODUCED IN BENIN AND TOGO

Cette étude vise la sélection d’arbres« plus » sur la base des caractères den- drométriques et des propriétés du bois dans des plantations de teck au Bénin et au Togo. La croissance de 569 arbres dans 5 forêts au Togo et 90 arbres dans 3 forêts au Bénin a été évaluée en mesu- rant le diamètre à hauteur de poitrine, la hauteur totale et la hauteur du fût. Les propriétés suivantes du bois ont été éva- luées et prises en compte pour la sélec- tion finale d’arbres « plus » : densité, pourcentage de bois de cœur et couleur. La durabilité naturelle du bois de cœur, le point de saturation des fibres, le module d’élasticité et les retraits ont été évalués sur la base de modèles spectroscopiques dans le proche infrarouge, préalablement construits. Nos résultats montrent qu’au Togo la variabilité inter-arbres en forêt est assez forte pour l’accroissement annuel en hauteur (0,81 ± 0,27 m), en circonfé- rence (2,95 ± 1,02 cm) et en hauteur des fûts (10,64 ± 3,51m). Au Bénin, si les per- formances dendrométriques des arbres ne varient pas de façon significative entre les forêts, pour la hauteur des fûts (10,99 ± 3,80 m), les valeurs du coeffi- cient de variation sont plus élevées (40 %) pour la forêt de Koto. Prenant en compte les propriétés du bois, la sélection finale multicritères montre que les peuplements d’Avétonou et de Tchorogo au Togo consti- tuent un groupe homogène affichant les plus fortes valeurs pour la densité du bois et le pourcentage de bois de cœur. Les arbres des forêts de Haho-Baloe et Eto ont des valeurs plus faibles pour la dura- bilité naturelle, le module d’élasticité, le pourcentage de bois de cœur et la densité du bois. Au Bénin, les arbres de la forêt d’Agrimey ont une densité plus élevée mais les valeurs pour le point de satu- ration des fibres, la durabilité naturelle et le retrait du bois sont similaires pour les trois forêts. La variabilité des perfor- mances dendrométriques et de la qualité du bois des arbres-candidat nous ont per- mis de sélectionner 33 arbres « plus ».

The Search for Antifungals from Amazonian Trees: A Bio-Inspired Screening

The anti-fungal activity of 60 extracts from 15 tree species in the French Guiana rainforest against human and wood-rotting fungi was studied. In this way (+)-mopanol (1) was isolated from the ethyl acetate extract of Peltogyne sp. (Caesalpiniaceae) wood. This work demonstrated that (1) the natural durability of wood can indeed guide the search for antifungal agents, (2) that extracts selected in this bio-inspired process exhibit a broad spectrum of antifungal activity and (3) that the method allows for the isolation of strongly active antifungals.

DURABILIDAD NATURAL Y DESCRIPCIÓN ANATÓMICA DE LA MADERA DE LA ESPECIE Caryodaphnopsis cogolloi Van der Werf

La revista Colombia Forestal publica manuscritos originales en temáticas del campo forestal y diversos aspectos de los recursos naturales y del medio ambiente, los cuales se discriminan en las categorías de artículo de investigación, de revisión, de reflexión y notas técnicas de acuerdo con lo estipulado por COLCIENCIAS para las publicaciones científicas. De acuerdo a la clasificación de áreas científicas de la Organización para la Cooperación y el Desarrollo Económico (OCDE), la revista Colombia Forestal pertenece al gran área de Ciencias Agrícolas(4), área de Agricultura, Silvicultura y Pesca(4A) y a la disciplina Forestal (4A02).

Wood natural durability testing under laboratory conditions: results from a round-robin test

In Europe, the durability of wood against wood-destroying basidiomycetes is tested according to CEN/TS 15083-1 (Durability of wood and wood-based products—determination of the natural durability of solid wood against wood-destroying fungi, test methods—part 1: basidiomycetes, 2005). Existing experience with this standard is quite heterogeneous wherefore six research institutions teamed up and established a new round-robin trial. Fagus sylvatica, Quercus robur, Robinia pseudoacacia as well as sap- and heartwood of Pinus sylvestris, were tested against Coniophora puteana and Trametes versicolor without any pre-treatment, with pre-leaching (EN 84) and with 6 months natural weathering of the specimens. Durability classification revealed differences between test laboratories and depended on pre-treatment and respective statistical measures applied.

Durabilidade Natural da Madeira de Quatro Espécies Florestais em Ensaios de Deterioração em Campo

This paper evaluates the natural durability of four wood species, so that they can be indicated or not, in situations of use in contact with the ground, the use in buildings and frame structures, or even in other applicability where there damage risks caused by biotic and abiotic factors. For this, was used four wood species from the north of the state of Mato Grosso, based on their availability, and especially in the commercial interest of woods for outdoors structures . The species used were: Tectona grandis (teca), Azadaractina indica (nim), Inga sp. (inga), Bagassa guianensis (tatajuba). Samples of the wood were exposed in field trials over 18 months and at the end was evaluated the percentage of mass loss and index decay . Among the species studied the Azadirachta indica wood showed the best results , however , the Bagassa guianensis wood showed the worst results for both the decay index as for mass loss . The density is not the main factor that adds natural durability of wood , but the content and type of extractives are contributing factors .

Natural durability of wood of ten native species from northeastern Mexico

Thorn scrub vegetation in Mexico is distributed over 50 million ha, where native tree species are the source of forage, timber, firewood and charcoal. Research describing wood durability of species from this vegetation type has not been fully determined, nor classified according to international standards. Thus, the aim of this study was to determine and classify the natural durability of ten woody species. Their natural durability was determined according to the European Pre-Norm 807, the loss of dynamic modulus of elasticity (MOEdyn) (MPa) was determined and wood mass loss (g) after being exposed to Trametes versicolor and Coniophora puteana fungi. Wood durability was classified according to the European Norm 350-1. Highly significant differences (p < 0.001) were found between the durability of woody species. The more durable species with lower MOEdyn lost were Condalia hookeri (57.5% ± 0.6%), Havardia pallens (58.2% ± 0.4%) and Acacia schaffneri (58.9% ± 6.3%). Species with lower mass loss after exposed to Coniophora puteana were Ebenopsis ebano (6.3% ± 1.9%), Condalia hookeri (8.6% ± 2.3%) and Cordia boissieri (11.8% ± 2.3%). E. ebano (7.1% ± 2.4%), Condalia hookeri (8.2% ± 2.5%) and Cordia boissieri (11.5% ± 3.1%) showed the lower mass lost after exposed to T. versicolor. According to European Norm 350-1, three woody species were classified as very durable and durable species.

Relationships between biochemical attributes (non-structural carbohydrates and phenolics) and natural durability against fungi in dry teak wood (Tectona grandis L. f.)

Non-structural carbohydrates and phenolic compounds are implicated in the natural durability of wood. In order to find the chemical traits of natural durability in teak wood, the radial distribution of phenolics compounds and non-structural carbohydrates were studied in trees ranked by contrasting natural durability class against Antrodia sp. Non-structural carbohydrates were analyzed by spectrophotometry after enzymatic assays and phenolics compounds using HPLC. High concentrations of starch, sucrose, glucose, and fructose were found in the sapwood, whereas only trace amounts were found in the heartwood. In the sapwood, low concentrations of H1 (a hydroxycinnamic acid derivative) were specifically detected. Tectoquinone was also detected in the sapwood but its content increased dramatically in the heartwood. 2-(Hydroxymethyl)anthraquinone and P1, an unidentified compound, were only detected in the heartwood and at high concentrations (>3 mg equivalent 5-methoxyflavone g−1 dry weight. Lower concentrations of 1,4-naphthoquinone, anthraquinone-2-carboxylic acid, and lapachol were also only detected in the heartwood. H1 and tectoquinone present in the sapwood could be considered as phenolic precursors of the synthesis of heartwood toxic phenolics in the heartwood. Correlations between natural durability and chemical composition of heartwood (quinone derivatives, P1, and non-structural carbohydrates) suggest that P1, 2-(hydroxymethyl)anthraquinone and tectoquinone could be natural durability traits. Heartwood extractives, mainly quinone derivatives, were formed from non-structural carbohydrates which were weakly correlated to natural durability.

Wood drying process: impact on Scots pine lumber durability

There are indications that the drying process may have negative effects on the natural durability of wood. The impact of various drying processes on the durability of Scots pine lumber has been evaluated with mass loss in a decay test with brown rot fungus, Coniophora puteana, as measure of the decay resistance of sapwood and inner and outer heartwood. Drying with or without steam conditioning was performed in six different series: air drying, kiln drying at temperature ranges commonly used in Swedish sawmills at 70°C and 90°C with two different regulation principles, and one high-temperature drying at 110°C. Durability varied considerably both between and within boards. Sapwood showed considerable less durability than heartwood. No difference in durability was found between inner heartwood and outer heartwood. Air-dried heartwood showed the highest durability compared to other drying series. The lowest durability in sapwood and heartwood was found for series dried at the 90°C temperature level with high material temperature early in drying. The interpretation is that the duration of high material temperature at high moisture content (MC) is the critical combination for decay resistance in heartwood. Steam conditioning after drying decreased durability in sapwood.

Thermogravimetry as a possible tool for determining modification degree of thermally treated Norway spruce wood

Thermal treatment is one of environmental friendly wood modification processes, developed in order to improve wood's natural durability and dimensional stability. Beside wood species, mainly isothermal temperature of heat- treatment and process duration affect these properties, which also correlate with the mass losses caused by the treatment. However, there is a lack of suitable external quality control methods. In this work thermogravimetry as a potential method for determining the degree of thermal modification is pre- sented. Several calibration curves, representing the mass losses in a certain temperature range (the values obtained from the TG curves) compared to weight losses caused by previous heat-treatment (known values), were established for spruce wood samples modified at different isothermal temperatures (from 170 to 220 C). Linear plot and good correlation factors (R 2 = 0.95 and 0.96) were obtained for the TG mass losses from 130 to 280 C and from 130 to 300 C, both under nitrogen atmosphere. The predominant cause of mass loss in this temperature region was depolymerisation and thermal decomposition of hemicelluloses residues. Lower correlation factors were obtained under the air atmosphere and in the wider temperature range, respectively.

Effect of compatibilizer on the natural durability of wood flour/high density polyethylene composites against rainbow fungus (Coriolus versicolor)

AbstractTo evaluate the effect of compatibilizer on the natural durability of wood flour/high density polyethylene composites against Coriolus versicolor, composites containing 25% and 50% by weight maple wood flour and 1% and 2% compatibilizer (Maleic anhydride polyethylene (MAPE)), respectively, were sampled. Identical specimens of the same composites without the compatibilizer were also prepared. Physical and mechanical properties of all specimens, including water absorption, flexural modulus, flexural strength, impact strength and hardness, were determined prior to and after incubation with the fungus for 14 weeks at 25°C and 75% relative humidity. Weight losses of the specimens were also determined after incubation. Results indicated that the compatibilizer had significant effects on the natural durability of the studied composite formulations so that all mechanical properties were affected by the fungus to greater extents in the case of uncompatibilized specimens than the compatibilized ones. Weight loss of the uncompatibilized composites was also higher than that of compatibilized ones. Higher water absorption was observed in all cases after incubation. However, the increase in water absorption was considerably higher in the case of uncompatibilized specimens. POLYM. COMPOS., 28:273–277, 2007. © 2007 Society of Plastics Engineers

Dauerhaftigkeit der europ�ischen Eiche (Quercus petraea und Quercus robur) gegen Wei�f�ulepilze (Coriolus versicolor): Beziehung zu Phenol-Extrakten

Knowledge on wood natural durability is required in order to be able to decide if we can use a certain type of wood outdoors. For instance, when used outside, oak wood is subjected to the leaching of its water-soluble substances. In this case the resistance of European oak wood is considered to be durable according to the European Standard EN 350-2. However, so far we do not exactly know the real impact of the leaching phenomenon on the resistance of oak wood and the importance of chemical contents. Nevertheless, our study has indicated that some individuals may contain highly durable wood characteristics even after the leaching process (i.e. 33% of very durable wood was still very durable after the leaching test). Chemical analysis has demonstrated that the presence of phenolic compounds are positively correlated with durability. This means that higher proportions of phenol confer higher resistance on wood. After the leaching test, which involves a washout of water soluble compounds, 70% of the trees demonstrate a decline in durability (after the leaching test 75% of the very durable wood dropped to a durable class; whereas, 25% of the wood in the same class still kept their very durable status). This experiment clearly shows the influence of the leaching phenomena and its important role on durability in oak wood. The results show also that 18% of the oak samples could be considered as very durable even after leaching.

Ocorrência de térmitas subterrâneos (Isoptera: Rhinotermitidae e Termitidae) e durabilidade natural da madeira de cinco essências florestais.

Avaliou-se a durabilidade natural da madeira de cinco essências arbóreas: Eucalyptus citriodora Hook, Gliricidia sepium (Jacq.) Steud, Lophantera lactescens Ducke, Piptadenia gonoacantha (Mart.) Macbr. e Samanea saman (Jacq.) Merr. O ensaio de campo foi realizado no campus da Universidade Federal Rural do Rio de Janeiro, de fevereiro de 2001 a novembro de 2002. Seis amostras de cada essência, parcialmente enterradas em posição vertical, foram dispostas aleatoriamente em cinco blocos. Em laboratório, segundo um sistema de notas relacionado ao estado fitossanitário da madeira, as amostras foram classificadas com um índice de comportamento, para cada essência, conforme seu aspecto fitossanitário. Também foram observados o estado da casca das amostras, a dureza da madeira e a presença de rachaduras longitudinais no corpo da amostra. As madeiras, mais e menos duráveis dentre os parâmetros avaliados, foram Laphantera lactescens e Piptadenia gonoacantha respectivamente. Em 47% das amostras que foram atacadas, três espécies de térmitas foram identificadas: Coptotermes havilandi, Nasutitermes jaraguae e Nasutitermes minor.