Wood Stain Research Articles

Application of plant essential oils in controlling wood mold and stain fungi

The antifungal activities of 19 plant essential oils against six wood mold and stain fungi (Aspergillus niger, Penicillium citrinum, Trichoderma viride, Botryodiplodia theobromae, Fusarium moniliforme, and Alternaria alternata) were investigated with the in vitro medium method. The chemical compositions and volatilization rates of the essential oils were analyzed by gas chromatography–mass spectrometry and oven heating, respectively. Antifungal effects of the essential oils on fresh Pinus massoniana wood were evaluated by dipping treatment. The average antifungal efficacies of the essential oils varied from 0.1 to 1.0, and oils of Cinnamomum cassia, Syzygium aromaticum, and Thymus mongolicus showed the greatest antifungal activities and completely inhibited the growth of all six fungi. The essential oils presented great differences in their main chemical components, and a significant negative linear correlation (Pearson correlation coefficient = -0.627, p < 0.01) was found between antifungal efficacy and volatilization rate, indicating that both chemical composition and volatilization rate are important factors influencing the antifungal activities of essential oils. Eight essential oils effectively inhibited the growth of fungi in Pinus massoniana wood with an absorption of 65.51 g/m2 ± 13.78 g/m2, and they have the potential to be environmentally friendly anti-mildew agents.

РАЦИОНАЛЬНОЕ ИСПОЛЬЗОВАНИЕ ДРЕВЕСИНЫ ДУБА МОРЕНОГО И НАТУРАЛЬНОГО

Fumed oak wood is valuable and one of the most environmentally friendly natural materials. As a result of a long stay of wood in flowing river water and in contact with bottom soil without air access, an individual process of staining of each trunk occurs. It consists in changing the chemical composition of the wood. The wood acquires increased strength and a beautiful color scheme. It is established that the degree of coloring of fumed oak wood depends on the amount of iron oxides in it (Fe2O3). There are industrial stocks of this wood in the Russian Federation. Drying process is one of the key technological operations. The most common methods of fumed oak wood drying are convective-atmospheric and convective-thermal ones. They have long duration, and the number of defects in warping and cracking reaches 30-40%. In this work, the drying of fumed oak wood by various methods has been investigated. It has been established that shrinkage of fumed oak wood is 1.5-2.0 times more than of natural oak woo. Preliminary thermochemical treatment enables to reduce the volumetric shrinkage of wood by 25%. An analysis of the color change of fumed oak wood depending on the conditions of wood staining in the river Voronezh has been made. Determination of the shrinkage quality and size is necessary to justify the allowances for obtaining sizes of lumber when cutting round wood. The studies performed will allow the rational and efficient use of valuable and unique oak wood

The Effect of Eutypella parasitica on the Wood Decay of Three Maple Species

Eutypella parasitica R.W. Davidson & R.C. Lorenz is the causative agent of Eutypella canker of maple, a destructive disease of maples in Europe and North America. The fungus E. parasitica is known to cause wood stain and decay. However, it is not known how effectively it decomposes the wood of the most widespread maple species in Europe. Wood samples of Acer pseudoplatanus L., A. platanoides L., and A. campestre L. were exposed to four isolates of E. parasitica and nine other fungal species for comparison, according to the modified EN 113 standard. After 15 weeks of incubation, mass loss and microscopical analysis of samples showed evidence of colonization and different wood decay potentials among fungal species. A highly significant positive correlation was found between mass loss and moisture content for all fungal species. Similarly, the measured cell wall thickness correlated well with the calculated mass loss of the samples. On average, the fungal species caused the lowest mass loss in A. pseudoplatanus (10.0%) and the highest in A. campestre (12.6%) samples. Among the samples exposed to E. parasitica isolates, the highest mass loss was recorded in A. pseudoplatanus (6.6%). Statistical analysis showed significant differences in mass loss and moisture content between different E. parasitica isolates. Based on the results of staining, we discuss the type of decay caused by E. parasitica. Although E. parasitica isolates caused smaller mass loss of samples compared to other more effective decay species, we should not disregard its capability of degrading maple wood. Because E. parasitica usually infects the lower portion of the trunk, which is the largest and most valuable part of the tree, any damage can cause significant economic and resource loss.

Comparison of Visual and Instrumental Assessment of Colour Differences on Finished Wooden Surfaces

Staining of wood with various substances and processes is an important part of surface finishing of wood. Colour differences as a result of staining and of exposure of coloured wood during its utilisation are usually evaluated by instrumental measurements. However, the measurement results can show something else compared to what our naked eye can see. Due to inhomogeneity of wood, this discrepancy can be even greater in the case of finished surfaces. The aim of our research was to evaluate distinctions between visual perception and numerically determined colour differences on differently finished wooden surfaces, to get information at which starting point the colour difference becomes visible, and to establish whether it is related to the nature of the surface. We established that the visual assessment is influenced by many factors and that there is a correlation between visual and instrumental assessments. The colour difference ΔE* of 0.5 should be considered as a value when it starts to become visible, and at the value of 2.0, observers already considered the colour difference as a different colour. It was stated that we have some tolerance in perceiving the colour change. This tolerance is more expressed in the case of transparent coating systems.

Catskills Bungalow and Wilderness Legend by Hudson River Inlay (Jeff Nelson)

Recognizing the contribution art has had in the Mayo Clinic environment since the original Mayo Clinic Building was finished in 1914, Mayo Clinic Proceedings features some of the numerous works of art displayed throughout the buildings and grounds on Mayo Clinic campuses as interpreted by the author.

Release and transformation of nanoparticle additives from surface coatings on pristine & weathered pressure treated lumber

As the market for “nano-enabled” products (NEPs) continues to expand in commercial and industrial applications, there is a critical need to understand conditions that promote release of nanomaterials and their degradation products from NEPs. Moreover, these studies must aim to quantify both the abundance and form (aggregates, ions, hybrids, etc.) of material released from NEPs to produce reasonable estimates of human and environmental exposure. In this work ZnO nanoparticles (NPs), a common additive in NEP surface coatings, were dispersed in Milli-Q water and a commercially available wood stain before application to pristine and weathered (outdoor 1 year) micronized copper azole pressure treated lumber (MCA). Coated lumber surfaces were sampled consecutively eight times using a method developed by the Consumer Product Safety Commission (CPSC) to track potential human exposure to ZnO NPs and byproducts through simulated dermal contact. Surprisingly, the highest total release of Zn was observed from aged lumber coated with ZnO NPs dispersed in wood stain, releasing 233 ± 26 mg Zn/m2 over the course of all sampling events. Alternatively, separate leaching experiments using a synthetic precipitation solution to simulate environmental release found aged lumber released significantly less Zn than pristine lumber when using the same coating formulation. Zinc speciation analysis also demonstrates that transformation of crystalline ZnO to Zn-organic complexes shortly after application to aged lumber. Regardless of experimental treatment, the majority of applied zinc (>75%) remains on the MCA surface. Finally, this work highlights how the nature of the screening technique (dermal contact vs. leaching) may result in different interpretations of exposure and risk.

Phylogenetic re-evaluation of the Grosmannia penicillata complex (Ascomycota, Ophiostomatales), with the description of five new species from China and USA

The Grosmannia penicillata complex (Ophiostomatales, Ascomycota) is one of the major species complexes in Leptographium sensu lato. Most of these are wood staining fungi associated with conifer-infesting bark beetles, and the complex encompasses the type species of the genus Grosmannia. Yet the phylogenetic relationships of species within the complex is unresolved. The aim of this study was to re-evaluate the circumscriptions of all known species in the G. penicillata complex, as well as isolates resembling G. penicillata obtained from a recent survey in China. Phylogenetic analyses of four gene regions: Internal transcribed spacer 2 and large subunit (ITS2-LSU), beta-tubulin (TUB), calmodulin (CAL), and translation elongation factor 1 alpha (TEF-1α) resolved the relationships of 15 species, including four new species (Grosmannia xianmiense sp nov., Grosmannia purpurea sp. nov., Grosmannia crassifolia sp. nov. and Grosmannia maixiuense sp. nov.), from China. Some isolates from pine in the USA that had previously been identified as Grosmannia abietina, represented a distinct taxon that is described here as Grosmannia xeno-abietina sp. nov.

Development of blue stain in mechanically harvested Scots pine (Pinus sylvestris) logs during storage

Blue stain is a type of discoloration that considerably lowers the aesthetic qualities of wood. During harvesting, fungal inoculum finds its way into the wood through places of cutting, delimbing, and damage to the tree stem. The development of peripheral blue stain in the logs of Scots pine (Pinus sylvestris L.) due to damage by a harvester head was investigated, using logs felled and delimbed with a chainsaw as reference. The development of blue stain was related to the age class of the stand, the date of felling, and the microclimatic conditions of the wood storage place. The mean surface area of blue stain in logs produced with the harvester was almost 35 cm2, approximately 30% larger than that of the reference logs. In stands of the fourth age class (diameter at breast height 32 cm), the surface of blue stain was more than two times larger than that of stands of the third age class (diameter at breast height 24 cm). The mean area of blue stain in wood stored after spring felling (19.3 cm2) was about 50% of that after summer felling (38.2 cm2). In particular, the development of blue stain in logs obtained with a harvester was visible between weeks 6 and 9 after spring felling and between weeks 3 and 6 after summer felling. For both felling dates, the range of blue stain depended less on air temperature around the wood stack and depended more on the duration of storage.

Effect of Thermo-Vibro-Mechanic® Densification Process on the Gloss and Hardness Values of Some Wood Materials

This study aimed to determine the gloss and hardness values of low-density wood materials densified using the Thermo-Vibro-Mechanic® (TVM) method after pretreatment with wood stain and wood preservative. This was carried out with a TVM density press that was designed and produced with the support of project 115O138 of the Scientific and Technological Research Council of Turkey (TUBITAK). The samples obtained from Uludağ fir (Abies bornmüelleriana Mattf.) and black poplar (Populus nigra L.) were pretreated with wood stain and wood preservative prior to the TVM densification process. The TVM densification operation was conducted at three different temperatures, three different vibration pressures, and three different vibration times. After the TVM densification process, changes in the gloss (ISO 2813 2014) and Brinell hardness values (TS 2479 1976) of the samples were determined. According to the results, the TVM densification method increased the gloss value of the Uludağ fir and black poplar wood pretreated with the wood preservative by 175% and 1390%, respectively, and increased the Brinell hardness value by 63% and 150%, respectively.

Study of antiseptic properties of the flame retardant solution provided by oxidized plant waste with regard to wood staining and mold micromycetes

Antiseptic properties of the obtained aqueous solution of pine wood flame retardant with regard to 25 types of micromycetes have been evaluated. In was shown that aqueous flame retardant solution suppressed actively such species as Aspergillus terreus Thorn., Discula pinicola (Naumov) Petr., Leptographium fungi lundbergii Lagerb. & Melin, Penicillium purpurogenum Stoll., Paecilomyces variotii Bainier. The obtained solution of flame retardant in concentration below than 3% showed that the average affected area for all tested groups of fungi was 50.4%. Therefore, this flame retardant solution was attributed to the medium effective antiseptic agent for pine wood.

Producing Spalted Alder Wood in Yunnan, China

Abstract Given the demand for environmentally friendly wood stains, dyeing by fungi has come to light as a suitable process for staining wood, textiles, and other materials. The identification of fungi capable of producing spalted wood merits considerable effort by researchers, and some spalted color or styles found on wood in the wild cannot be cultivated in the laboratory. To find additional fungal candidates and styles for spalting in China, we here collected and identified wood fungi in Yunnan and Guangxi in China. Fungi were purchased or isolated and then inoculated to alder wood blocks (Alnus nepalensis D. Don). Out of seven purchased strains, three formed zone lines, but it was unclear whether Chlorociboria aeruginascens cfcc 87397 could do so. Out of 20 strains, 15 species were isolated from wood forming zone lines with surface black pigments, and only Diaporthe sp. ZXH63-4 formed additional yellow pigments accompanied by zone lines throughout the wood, which is a new means of forming yellow pigments and black zone lines at the same time. Some fungi collected from stained wood samples showed reddish-brown zone lines, but they showed black zone lines when isolated and inoculated on alder.

Treatment of coconut palm wood using inorganic preservatives

Freshly felled coconut wood is very much susceptible to wood boring insects, moulds and stain fungi as it has high levels of sugar, starch and moisture content throughout the trunk. The objective of this study was to develop appropriate preservative methods to protect sawn coconut palm wood from insects and other pathogens under the prevailing eco-climatic conditions in Kerala and to evaluate the effect of different preservative factors on the treatability of coconut wood. Wood samples were treated with inorganic chemicals like Copper Chrome Boron - CCB and Borax Boric Acid – BBA by diffusion and pressure treatment, of which pressure treatment performed better. Diffusion treatment of inorganic preservatives in high and medium density wood showed no significant difference in retention whereas significant difference was observed for penetration percentage. For pressure treatment, retention and penetration were significant in high density wood whereas medium density wood showed only significant retention. Solution concentrations and overall retention and penetration percentage were found to be significantly related. The study found that sawn coconut wood samples could be effectively treated with preservatives complying with the prescribed retention and penetration percentages as per the different standards and therefore, could be used as a potential substitute for conventional timbers and the insect damage was negligible. No incidence of insects, particularly termites and pin hole borers was observed during the graveyard studies.

Non-linear release dynamics for a CeO2 nanomaterial embedded in a protective wood stain, due to matrix photo-degradation

The release of CeO2-bearing residues during the weathering of an acrylic stain enriched with CeO2 nanomaterial designed for wood protection (Nanobyk brand additive) was studied under two different scenarios: (i) a standard 12-weeks weathering protocol in climate chamber, that combined condensation, water spraying and UV–visible irradiation and (ii) an alternative accelerated 2-weeks leaching batch assay relying on the same weathering factors (water and UV), but with a higher intensity of radiation and immersion phases. Similar Ce released amounts were evidenced for both scenarios following two phases: one related to the removal of loosely bound material with a relatively limited release, and the other resulting from the degradation of the stain, where major release occurred. A non-linear evolution of the release with the UV dose was evidenced for the second phase. No stabilization of Ce emissions was reached at the end of the experiments. The two weathering tests led to different estimates of long-term Ce releases, and different degradations of the stain. Finally, the photo-degradations of the nanocomposite, the pure acrylic stains and the Nanobyk additive were compared. The incorporation of Nanobyk into the acrylic matrix significantly modified the response of the acrylic stain to weathering.

Very low concentration of cerium dioxide nanoparticles induce DNA damage, but no loss of vitality, in human spermatozoa

Cerium dioxide nanoparticles (CeO2NP) are widely used for industrial purposes, as in diesel, paint, wood stain and as potential therapeutic applications. The Organization for Economic Cooperation and Development included CeO2NP in the priority list of nanomaterials requiring urgent evaluation. As metal nanoparticles can cross the blood-testis barrier, CeO2NP could interact with spermatozoa. The genotoxicity of CeO2NP was demonstrated in vitro on human cell lines and mouse gametes. However, the effects of CeO2NP on human spermatozoa DNA remain unknown. We showed significant DNA damage induced in vitro by CeO2NP on human spermatozoa using Comet assay. The genotoxicity was inversely proportional to the concentration (0.01 to 10 mg·L−1). TEM showed no internalization of CeO2NP into the spermatozoa. This study shows for the first time that in vitro exposure to very low concentrations of cerium dioxide nanoparticles can induce significant DNA damage in human spermatozoa. These results add new and important insights regarding the reproductive toxicity of priority nanomaterials, which require urgent evaluation.

Environmental exposure of a simulated pond ecosystem to a CuO nanoparticle-based wood stain throughout its life cycle

Indoor aquatic mesocosms were used to assess the behavior of a wood stain containing CuO nanoparticles in a simulated pond ecosystem for 1 month.

Dermal transfer and environmental release of CeO2 nanoparticles used as UV inhibitors on outdoor surfaces: Implications for human and environmental health

A major area of growth for “nano-enabled” consumer products have been surface coatings, including paints stains and sealants. Ceria (CeO2) nanoparticles (NPs) are of interest as they have been used as additives in these these products to increase UV resistance. Currently, there is a lack of detailed information on the potential release, and speciation (i.e., ion vs. particle) of CeO2 NPs used in consumer-available surface coatings during intended use scenarios. In this study, both Micronized-Copper Azole pressure-treated lumber (MCA), and a commercially available composite decking were coated with CeO2 NPs dispersed in Milli-Q water or wood stain. Coated surfaces were divided into two groups. The first was placed outdoors to undergo environmental weathering, while the second was placed indoors to act as experimental controls. Both weathered surfaces and controls were sampled over a period of 6months via simulated dermal contact using methods developed by the Consumer Product Safety Commission (CPSC). The size and speciation of material released was determined through sequential filtration, total metals analysis, X-Ray Absorption Fine Structure Spectroscopy, and electron microscopy. The total ceria release from MCA coated surfaces was found to be dependent on dispersion matrix with aqueous applications releasing greater quantities of CeO2 than stain based applications, 66±12mg/m2 and 36±7mg/m2, respectively. Additionally, a substantial quantity of CeO2 was reduced to Ce(III), present as Ce(III)-organic complexes, over the 6-month experimental period in aqueous based applications.

Biocontrol potential of Bacillus subtilis B1 against sapstain fungus in rubber wood

Rubber wood, one of the most preferred plantation timbers in the tropical regions, is easily prone to various moulds, decay and stain fungi. Lasiodiplodia theobromae, the dominant sapstain fungus of rubber wood, causes high economic loss to the industry through its bluish black sap wood discolouration. In our previous laboratory trials, Bacillus subtilis B1 isolated from market available compost was proved as a potent biocontrol agent against the sapstain fungus L. theobromae. The main aim of the present study was to demonstrate the biocontrol potential of B. subtilis B1 against rubber wood sapstain fungus on fresh rubber wood pieces during pre-monsoon, southwest monsoon and northeast monsoon seasons in the field. The visual ratings provided for the wood fungal growth and internal wood stain exhibited the bio-protectant efficiency of B. subtilis B1 even in the southwest monsoon season, which is considered as the most favourable period for the wood fungal growth. Biocontrol agent, B. subtilis B1 demonstrated significant inhibitions of sapstain fungus on open stacked rubber wood pieces in all the seasons. The frequent rainfalls during monsoon periods provide a conducive environment for fungal growth on felled rubber wood. Successful field evaluations of the biocontrol agent during pre-monsoon, monsoon and post-monsoon periods would guarantee year round protection against rubber wood sapstain. B. subtilis B1 displayed holistic biocontrol efficiency towards other stain (Ceratocystis sp., Fusarium sp.), mould (Aspergillus sp., Penicllium sp.) and decay fungi (Trametes versicolor) as well.

The fungal composition of natural biofinishes on oil-treated wood

BackgroundBiofinished wood is considered to be a decorative and protective material for outdoor constructions, showing advantages compared to traditional treated wood in terms of sustainability and self-repair. Natural dark wood staining fungi are essential to biofinish formation on wood. Although all sorts of outdoor situated timber are subjected to fungal staining, the homogenous dark staining called biofinish has only been detected on specific vegetable oil-treated substrates. Revealing the fungal composition of various natural biofinishes on wood is a first step to understand and control biofinish formation for industrial application.ResultsA culture-based survey of fungi in natural biofinishes on oil-treated wood samples showed the common wood stain fungus Aureobasidium and the recently described genus Superstratomyces to be predominant constituents. A culture-independent approach, based on amplification of the internal transcribed spacer regions, cloning and Sanger sequencing, resulted in clone libraries of two types of biofinishes. Aureobasidium was present in both biofinish types, but was only predominant in biofinishes on pine sapwood treated with raw linseed oil. Most cloned sequences of the other biofinish type (pine sapwood treated with olive oil) could not be identified. In addition, a more in-depth overview of the fungal composition of biofinishes was obtained with Illumina amplicon sequencing that targeted the internal transcribed spacer region 1. All investigated samples, that varied in wood species, (oil) treatments and exposure times, contained Aureobasidium and this genus was predominant in the biofinishes on pine sapwood treated with raw linseed oil. Lapidomyces was the predominant genus in most of the other biofinishes and present in all other samples. Surprisingly, Superstratomyces, which was predominantly detected by the cultivation-based approach, could not be found with the Illumina sequencing approach, while Lapidomyces was not detected in the culture-based approach.ConclusionsOverall, the culture-based approach and two culture-independent methods that were used in this study revealed that natural biofinishes were composed of multiple fungal genera always containing the common wood staining mould Aureobasidium. Besides Aureobasidium, the use of other fungal genera for the production of biofinished wood has to be considered.

Botryosphaeriaceae Species Associated With Cankers and Dieback Symptoms of Acacia mangium and Pinus caribaea var. hondurensis in Venezuela.

Several species in the Botryosphaeriaceae family cause wood stain, cankers, and dieback of trunks and branches in a wide range of forest tree species. The aim of this study was to characterize the botryosphaeriaceous fungi associated with decline symptoms observed in Acacia mangium and Pinus caribaea var. hondurensis, two economically important forest tree species grown in commercial plantations in Venezuela. Fungi isolated from symptomatic samples collected from both hosts in commercial sites were identified based on their morphology and DNA sequences of the internal transcribed spacer region (ITS1-5.8S-ITS2) and part of the β-tubulin and translation elongation factor 1-α genes. Lasiodiplodia theobromae and L. venezuelensis were routinely isolated from A. mangium and P. caribaea var. hondurensis. Additionally, the novel species Diplodia guayanensis was isolated and characterized from symptomatic and asymptomatic tissues of A. mangium. Multigene phylogenetic analyses along with restriction fragment length polymorphism studies further supported the identification of these species. A pathogenicity study was conducted under natural conditions and 12 weeks after inoculation all Botryosphaeriaceae spp. were shown to be highly virulent on A. mangium. Contrary, no lesions were observed in the wood of P. caribaea var. hondurensis when inoculated with L. theobromae and L. venezuelensis. However, both species were consistently reisolated from the asymptomatic tissue beyond the inoculation point. This study contributes to a better understand the role that species in the Botryosphaeriaceae play on disease symptoms and dieback of A. mangium and P. caribaea var. hondurensis from plantations in eastern Venezuela.

Application of copper monoethanolamine solutions as primers for semitransparent exterior wood stains

The effects of copper monoethanolamine (CuA) treatment of wood surfaces on the surface weathering and durability of a semitransparent penetrating stain were compared with those of chromic acid (CrA) treatment which is known as a photoprotective primer, using artificial weathering trials. Chemical changes in chemically treated and untreated wood surfaces during artificial weathering were investigated using Fourier transform infrared (FTIR) spectroscopy. Surface roughness, water contact angle measurements and scanning electron microscopy observations were performed to assess stain durability. Results of FTIR analyses indicated that lignin losses following CuA and CrA treatment were less than those of the untreated wood surfaces during the initial stage of artificial weathering. CuA pretreatment prior to staining also retarded the increase in the average surface roughness compared with that observed for the CrA-pretreated surface and untreated control (only stained) during artificial weathering. Furthermore, CuA pretreatment retarded the decrease in the contact angle compared with that observed for the untreated control, although the use of a highly concentrated CuA solution led to a decrease in the water repellency of the stained wood surface. These results indicated that CuA solution could be used for the pretreatment of wood surfaces to enhance the durability of semitransparent penetrating stains, as long as excessive CuA concentrations are avoided.