Alder Wood Research Articles

Wetting Behavior of Alder (Alnus cordata (Loisel) Duby) Wood Surface: Effect of Thermo-Treatment and Alkyl Ketene Dimer (AKD)

The main purpose of this study was to investigate the hydrophobic effect and chemical changes induced by thermo-treatment and alkyl ketene dimer (AKD) on the surface properties of Alder (Alnus cordata (Loisel) Duby) wood before and after an artificial weathering test. Thermal treatment was conducted at a temperature of 200 °C for 4 h in a thermo-vacuum cylinder. Then, the paper sizing agent, AKD at different concentrations of a solution of 0.1%, 0.5% and 10% was used as a potential hydrophobizing reagent for untreated and thermally treated alder wood surfaces. The contact angle measurement, ATR-FTIR analysis and colour variation were carried out for the samples. The preliminary results revealed that the contact angle values of the wood materials increased with thermal modification. However, the influence of the thermal treatment on hydrophobicity was small when compared to the substantial effect of the AKD application in this respect, and also after the artificial weathering test. The FTIR analysis supported the hypothesis that AKD could make bonds chemically stable even when using a small concentration of AKD. The findings acquired in this work provide important information for future research and the utilization of the AKD on lesser-used wood species.

Genome description of Phlebia radiata 79 with comparative genomics analysis on lignocellulose decomposition machinery of phlebioid fungi

BackgroundThe white rot fungus Phlebia radiata, a type species of the genus Phlebia, is an efficient decomposer of plant cell wall polysaccharides, modifier of softwood and hardwood lignin, and is able to produce ethanol from various waste lignocellulose substrates. Thus, P. radiata is a promising organism for biotechnological applications aiming at sustainable utilization of plant biomass. Here we report the genome sequence of P. radiata isolate 79 originally isolated from decayed alder wood in South Finland. To better understand the evolution of wood decay mechanisms in this fungus and the Polyporales phlebioid clade, gene content and clustering of genes encoding specific carbohydrate-active enzymes (CAZymes) in seven closely related fungal species was investigated. In addition, other genes encoding proteins reflecting the fungal lifestyle including peptidases, transporters, small secreted proteins and genes involved in secondary metabolism were identified in the genome assembly of P. radiata.ResultsThe PACBio sequenced nuclear genome of P. radiata was assembled to 93 contigs with 72X sequencing coverage and annotated, revealing a dense genome of 40.4 Mbp with approximately 14 082 predicted protein-coding genes. According to functional annotation, the genome harbors 209 glycoside hydrolase, 27 carbohydrate esterase, 8 polysaccharide lyase, and over 70 auxiliary redox enzyme-encoding genes. Comparisons with the genomes of other phlebioid fungi revealed shared and specific properties among the species with seemingly similar saprobic wood-decay lifestyles. Clustering of especially GH10 and AA9 enzyme-encoding genes according to genomic localization was discovered to be conserved among the phlebioid species. In P. radiata genome, a rich repertoire of genes involved in the production of secondary metabolites was recognized. In addition, 49 genes encoding predicted ABC proteins were identified in P. radiata genome together with 336 genes encoding peptidases, and 430 genes encoding small secreted proteins.ConclusionsThe genome assembly of P. radiata contains wide array of carbohydrate polymer attacking CAZyme and oxidoreductase genes in a composition identifiable for phlebioid white rot lifestyle in wood decomposition, and may thus serve as reference for further studies. Comparative genomics also contributed to enlightening fungal decay mechanisms in conversion and cycling of recalcitrant organic carbon in the forest ecosystems.

Polypore fungi of Caucasian alder as a source of antioxidant and antitumor agents

Macroscopic fungi on Caucasian alder wood (Alnus subcordata) were identified and tested as a source of betulin and betulinic acid (the most important metabolites of the Betulaceae family) to evaluate levels of phenols, flavonoids and antioxidant activity. Ganoderma applanatum, Lenzites betulina, Trichaptum biforme, Rigidoporus ulamrius, Fomes fomentarius, Schizophyllum commune, Auricularia mesenterica, and Trametes versicolor were among those identified, and they differed significantly in the level of betulin and betulinic acid and phenols, flavonoids and antioxidant properties in fungal tissues extracted with methanol and with ethanol (p ≤ 0.01). G. applanatum had the most betulin (3.642%) and S. commune the most betulinic acid (1.413%). All tested fungi had high antioxidant activity, and L. betulina had the highest (97.775%). The highest amounts of phenol (719.993 mg mL−1) and flavonoids (361.403 mg mL−1) were found in the ethanolic extract from G. applanatum. Considering the results of this study and the low cost and convenient access to these fungi, they should be good sources for producing different drugs.

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.

The wooden foundations of Rialto Bridge (Ponte di Rialto) in Venice: Technological characterisation and dating

Abstract The wooden foundations of Ponte di Rialto (Rialto Bridge), the oldest and most famous of the four bridges spanning the Grand Canal in Venice, Italy, were analysed in order to determine the tree species used to construct the foundation, to examine the timber's present-day physical and mechanical properties and to identify construction periods. The material recovered during geotechnical surveys underwent micro-morphological, physical, chemical and mechanical analyses. The radiocarbon method was used for dating purposes. The footings of the bridge's foundations, mostly consisting of alder wood, were shown to be in good overall condition generally. A comparison of normal and polarised light images of wooden cross-sections showed abundant crystalline cellulose within the cell walls, indicating that the state of conservation of the waterlogged samples is very close to that of sound alder wood. Only one alder sample showed signs of severe bacterial attack, mostly concentrated in the fibre cell walls. Radiocarbon dating identified two distinct construction periods. One sample dates to 1570 AD ± 85, whilst another dates to the year 960 AD ± 59. The later dating corresponds to the construction of the stone bridge that still exists today. The earlier period, around the year 1000, likely refers to the foundations of the first bridge, built after several pontoon bridges, and corresponding to the initial Ponte della Moneta.

Evaluation of Selected Properties of Alder Wood as Functions of Sanding and Coating

The objective of this study was to optimize the sanding and coating processes of black alder wood to promote and support its use in furniture manufacturing. Two criteria have been applied for process optimization, namely, the minimum surface roughness of the samples and power consumption during sanding as a function of various sanding systems. The surface roughness of the sanded specimens and the power consumption during sanding strongly depends on the grit size used. Two eco-varnishes were applied to the samples by spraying. Moreover, the effect of the surface preparation and varnish type on the coating properties expressed by the varnish layer adherence to the substrate and surface glossiness was evaluated. For better glossiness values, the UV-cured varnish was preferred. The sanding with a grit sequence of 60, 120, and 150 grit size abrasives was found to be optimal when applied to black alder wood, and it is recommended to obtain performant UV-coated wood surfaces for furniture products.

Integrate measurements allow the surface characterization of thermo-vacuum treated alder differentially coated

The objective of this work was to investigate color stability and chemical changes of thermo-treated artificially weathered and coated alder (Alnus cordata, Loisel.) samples. Specimens were thermo-treated at a temperature of 200 °C for 4 h and then coated with commercially manufactured finishes. A solar box test chamber was employed for weathering of the samples. The color change of the specimens were measured using CIE L∗a∗b∗ color space system. Changes of the chemical composition in the samples were evaluated using UV–Vis-NIR and FTIR spectroscopy techniques. The results of these different analytical techniques all indicate the same outcome and consistently corroborate the color measurements before and after UVB exposure. The results revealed that thermo-treated alder wood, coated with various finishes, exhibited a strong variation of color compared to that of control specimens indicating of thermal modification was not very effective in restrictingUVlight induceddegradationin the specimens.

Utilization of lignin powder for manufacturing self-binding HDF

AbstractThe preparation of self-binding lignocellulosic fibreboards has been investigated. Different high-density fibreboards (HDF) were hot-pressed based on a mixture of grey alder (Alnus incanaL. Moench) wood chips processed by steam explosion auto-hydrolysis (SE) and 15% or 25% lignin content from three different industrial sources: softwood kraft lignin (SWKL), soda wheat straw lignin (SoWhStL) and hydrolysis wheat straw lignin (HWhStL). Density, thickness swelling (TS) after immersion in water for 24 h, modulus of rupture (MOR), modulus of elasticity (MOE) and strength of internal bond (IB) of the board samples were determined. The amount (15% or 25%) and moisture content (MC) (18±1% or 5±2%) of the added lignin affected all the tested properties of the HDF except for density. However, the kind of the added lignin affects the obtained fibreboard more significantly compared to the control sample made without an admixture of lignin. In some cases, the tested values were diminished to half. The tested properties of the HDF samples produced with SoWhStL or HWhStL are compatible with standard requirements for medium-density fibreboard (MDF) for general use under dry conditions (EN 622-5, MDF), however, it depends on the lignin amount and MC.

Fractionation of technical lignin with ionic liquids as a method for improving purity and antioxidant activity

Alder soda lignin, a by-product of the chemical processing of black alder wood, was fractionated using ionic liquids (ILs) based on the 1-buthyl-3-methylimidazolium [Bmim] cation and the following anions: chloride ([Bmim]Cl), dimethylphosphate ([Bmim]Me2PO4), acetate ([Bmim]OAc) and tosylate ([Bmim]OTs). The aim was to obtain lignin fractions of improved purity for further application as antioxidants. The purity and properties of the IL lignin fractions were compared with those of other lignin fractions obtained using sequential extraction with organic solvents. The original lignin and the lignin fractions were characterized by analytical pyrolysis (Py-GC/MS/FID), size-permeation chromatography (GPC), electron paramagnetic resonance (EPR) spectroscopy and wet chemistry methods. The lignin treatment with [Bmim]DMP, [Bmim]OAc and [Bmim]OTs produced fractions with a lignin content of 98–99%. These fractions along with the n-propanol and methanol fractions obtained using sequential organic solvent extraction were enriched with certain structural features that had a positive impact on lignin antioxidant activity, according to the results from DPPH and ORAC assays.

Yield of Stirred Cold Maceration and Extraction of Milled European Black Alder Wood and Bark using Different Solvents

Wood extractives, especially polyphenols, have great influence on the xylem colour of many wood species, which affects the success of hydrothermal wood processing, such as wood drying. One such wood species is European black alder (Alnus glutinosa (L.) Gaertn.), which is prone to forming intense and uneven reddish-orange or reddish-brown discolourations immediately upon harvesting and processing. However, there is lack of published scientific data on the wood and bark extractives of black alder, as well as the most suitable solvents to extract them. In this work, total soluble extractives, phenols, and flavonoids have been quantified in the wood and bark of black alder. Furthermore, the influence of four different polar organic solvents and deionized water on extractives removal yields has been measured. It was found that the bark has much higher levels of extractives as compared to the wood. Furthermore, it has been found that the highest extractive yields were obtained by using methanol as the extraction solvent for all observed compound group classifications.

Record of vegetation, climate change, human impact and retting of hemp in Garhwal Himalaya (India) during the past 4600 years

This study is focused on a 3.55-m-long sediment core retrieved from Badanital (i.e. the BT core) in 2008. Badanital (30°29′50″N, 78°55′26″E, 2083 m a.s.l.) is a small lake located in the upper catchment area of the Ganges in Garhwal Himalaya, northern India. The lake and the regional broad-leaved semi-evergreen forests are under the influence of the Indian Summer Monsoon (ISM) and westerly associated cyclones. Palynological investigation of the BT core revealed past vegetation changes reflecting both climate and human impact during the last 4600 years. Maximum spread of oaks occurred during c. AD 550–1100 and c. AD 1400–1630, that is, the intervals which partly overlap with the ‘Medieval Warm Period’ and the ‘Little Ice Age’, respectively. Three intervals of decreased oak pollen percentages are attributed to (1) continuously drier and cooler climatic conditions and fire activity ( c. 2600–500 BC), (2) severe reduction in oak forests followed by secondary succession of alder woods ( c. AD 1150–1270) and (3) pre-modern settlement activities since the British imperial occupation (after c. AD 1700). We argue that the high percentages (i.e. up to 28%) of Humulus/ Cannabis type and Cannabis type pollen point to intense local retting of hemp c. 500 BC–AD 1050. Based on our age model, Cannabis fibre production at Badanital is contemporaneous with archaeological records of ancient hemp products from different parts of Eurasia suggesting possible linkages to early trade and knowledge exchange routes connecting India and the Himalaya with Central and East Asia and possibly Europe.

Some Coating Properties of Black Alder Wood as a Function of Varnish Type and Application Method

The objective of this study was to evaluate the adhesion strength and glossiness of black alder wood (Alnus glutinosa Gaertn. L.) coated with water-borne and UV varnishes by two application systems. Prior to coating, the samples were prepared by sanding with four combinations of grit size sandpapers, 180 being the final grit. The surface quality of the specimens was measured with a white light profilometer. Any increase in grit size gradually reduced surface roughness, which further influenced the overall coating performance of the samples. UV varnish applied by roller presented higher adhesion strength and gloss as compared to spraying. The specimens varnished with a water-borne finish by spraying exhibited a better adherence to the substrate than those of UV varnished samples by the same method and provided glossiness at 60° geometry in the same range. These results are valuable for the furniture manufacturing industry for generating a better use and efficiency of secondary wood resources in order to achieve value-added products.

Influence of pyrolysis temperature and hardwood species on resulting biochar properties and their effect on azimsulfuron sorption as compared to other sorbents

Azimsulfuron is an acidic herbicide with a high water solubility which makes risk of groundwater contamination a concern. Various wood based biochars produced at different pyrolysis temperatures were characterized along with their sorption capacity for the herbicide azimsulfuron. In addition, we compared sorption on biochars with sorption on mineral sorbents such as clay minerals and iron oxides. In biochar formed at high temperatures (500°C and 700°C), FT-IR studies confirmed the increase in aromaticity. Scanning electron microscope (SEM) images of the biochars showed differences in the macroporous structure and lower size pores at higher temperatures. SSA (Specific Surface Area) of the biochars increased with pyrolysis temperature and, for all different biochars, this resulted in higher sorption of azimsulfuron. In the case of mineral sorbents, sorption is not related to SSA. Higher sorption is observed in a montmorillonite, of lower SSA, than in mixture of clay minerals with 30% smectite (w/w). On the contrary as with the clays, sorption on the two iron oxyhydroxides increased with SSA. Desorption studies showed hysteresis. Leaching studies showed no effect on azimsulfuron retention on soil column amended with apple wood biochar, while a reduction of azimsulfuron in leachates in soil columns amended with the modified montmorillonite and alder wood biochar (500°C). Total retention was shown for alder wood biochar.

From wetland to commercial centre: the natural history of Wyspa Spichrzów (“Granary Island”) in medieval Gdańsk, northern Poland

This paper describes the analyses of pollen, non-pollen palynomorphs, macroremains and geochemistry in sediments from archaeological excavations at Wyspa Spichrzow (“Granary Island”) in Gdansk, northern Poland. The aim of this study was to reconstruct the environmental conditions in this part of the town in the period preceding its occupation and during its transformation with the establishment of a trade centre and an increasing number of granaries, warehouses and workshops. The results show that this area was originally covered by wetlands typical of river oxbows, with a landscape formed by alder woods, shallow pools of water, fens and patches of wet meadows. Around the 9th–10th centuries, a distinct lowering of the groundwater table reduced the pools, and the alder stands also reduced. These changes coincided with the Medieval Climatic Anomaly. Drying of the ground could have been an important factor enabling expansion of settlement in the Gdansk area. Between the 10th and 13th–14th centuries, the area around the investigated sites was probably used as pasture, as shown by high frequencies of coprophilous fungal spores. A large representation of cereal pollen and pollen and macroremains of field weeds reflects crop transport and storage on the island from ca. the 13th/14th centuries in the northern part of the area and the 15th/16th centuries in its southern part. The increasing human impact caused development of a rich flora associated with human activities, habitat enrichment by nitrogen and phosphorus, and heavy metal pollution from the beginning of the 13th century.

Vascular flora of the Viešvilė State Strict Nature Reserve and its buffer zone (West Lithuania)

Abstract The paper presents analysis of the results of floristic studies carried out over 25 years in the Viešvilė State Strict Nature Reserve (VSSNR) and its buffer zone. The list of 703 vascular plant species including the data on their distribution and dynamics of abundance are provided. The native flora of the VSSNR includes 580 species, i.e. amounts to 47% of all native vascular plant species recorded in Lithuania. Since 1991, after the establishment of the Reserve, 15 species have become extinct and 30 have become endangered as a result of natural succession. Among 37 alien species recorded in the Reserve, four species are penetrating into natural habitats and threatening their existence. It was ascertained that about half of all species were recorded in meadows and glades of the forests, i.e. in the habitats, which occupy less than 1% of the whole territory. These are also habitats of most extinct and endangered species. Riparian and fontinal black alder woods are the most rich in vascular plant species among forest habitats.

Conversion of black alder (Alnus glutinosa L.) in supercritical solvents

ABSTRACTIn this study, black alder (Alnus glutinosa L.) wood samples were subjected to supercritical fluid extraction (SFE) using acetone, methanol, and water as solvent. The highest yield (62.4%) of SFE was obtained from black alder with water solvent at 678 K. The supercritical fluid extracts were fractionated into water soluble, acetone soluble, phenolic, fatty acid, polar, and nonpolar fractions. The lowest and highest yields of phenolic fractions from the supercritical water extraction runs were 5.3% and 15.4%. The lowest and highest yields of polar fractions from the supercritical water extraction runs were 14.6% and 16.7%. Increases of higher heating values (HHVs) in the supercritical fluid extracts are range from 48.1% to 71.4%, from 41.7% to 67.2%, and from 34.4% to 61.9% for acetone, methanol, and water, respectively. Carbon and hydrogen contents in supercritical fluid extracts are higher than those of in the original black alder sample.

Anatomical study of short-term thermo-mechanically densified alder wood veneer with low moisture content

The effects of short-term thermo-mechanical (STTM) densification by varying temperature and pressure regimes on the changes in anatomical structure of alder wood (Alnus glutinosa Gaertn.) veneers with low moisture content (~5 %) were investigated. Scanning electron microscopy (SEM) images of oblique cross and radial sections of non-densified and densified alder veneer were analysed. Veneer sheets were densified using pressure levels of 4, 8 and 12 MPa at three temperatures: 100, 150 and 200 °C for a short time of 4 min. The obtained results show that STTM densification of veneers causes irreversible changes in their morphology. Significant deformation of vessels and fibres and appearance of small spherical-like droplets (condensing compounds of lignin and degradation products of hemicelluloses) on the surface of the cell wall as well as pronounced thermo-mechanical wrinkling accompanied by the formation of axial cracks and rippled surface of the cell wall of the vessels were observed at higher temperatures and pressures. SEM images showed that the cell lumens collapsed and a certain amount of fractures in cell walls developed with increasing densification temperature and pressure. Moreover, densification of veneer with low moisture content at high temperatures and pressures causes a considerable fragility and occurrence of thermal erosion of the cell wall of vessel elements and fibres.

Technological and Thermal Properties of Thermoplastic Composites Filled with Heat-treated Alder Wood

This study investigated the effect of heat-treated wood content on the water absorption, mechanical, and thermal properties of wood plastic composites (WPCs). The WPCs were produced from various loadings (30, 40, and 50 wt%) of heat-treated and untreated alder wood flours (Alnus glutinosa L.) using high-density polyethylene (HDPE) with 3 wt% maleated polyethylene (MAPE) coupling agent. All WPC formulations were compression molded into a hot press for 3 min at 170 oC. The WPCs were evaluated using mechanical testing, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The mechanical property values of the WPC specimens decreased with increasing amounts of the heat-treated wood flour, except for the tensile modulus values. The heat treatment of alder wood slightly increased the thermal stability of the WPCs compared with the reference WPCs. The crystallization degree (Xc) and the enthalpy of crystallization of the WPCs slightly decreased with increasing content of the heat-treated wood flour. However, all WPCs containing the heat-treated alder wood flour showed a higher crystallinity degree than that of the virgin HDPE.

The effect of growth conditions in specific areas of Croatia and the Czech Republic on the physical and mechanical properties of black alder wood (Alnus glutinosa Gaertn.)

In this paper, static bending (modulus of rupture, MOR, and modulus of elasticity, MOE) and compression strength parallel to grain (σ cǀǀ ) of black alder wood (Alnus glutinosa Gaertn.) were investigated. For experimental testing, we used black alder wood from two different areas: Crni Jarci, Croatia, and Mala Bystřice, Czech Republic. Experimental tests were carried out according to the Czech national standards: CSN 49 0115 and CSN 49 0116 for static bending and CSN 49 0110 for compression strength. The samples from Mala Bystřice showed lower values of MOR (~14%), MOE (~30%), and σ cǀǀ (~4%), when compared to the samples from Crni Jarci. The relationship between density and strength was investigated. The difference between the studied groups at the 0.05 significance level was confirmed. The average linear correlation was found between density and the observed mechanical properties (for σ cǀǀ ). The average density was 549 kg m -3 for samples from Crni Jarci and 469 kg m -3 for samples from Mala Bystřice. The results were compared with values indicated in similar studies.

Recovery of the herbaceous layer in the young silver birch and black alder stands that developed spontaneously after a forest fire

AbstractThe studies, which were conducted in southern Poland, focused on the recovery of the herb layer in 17‐year‐old post‐fire silver birch and black alder forests. Although both types of stands, which are of the same age, developed spontaneously, the alder stands occupied damper sites (with thicker A horizons that survived the fire) than those in the birch forests. We surveyed the migration rates of 44 woodland species, primarily ancient woodland indicators, into both forests and the potential differences in these rates depending on their moisture regime and the community type represented by unburned forests, which were treated as the source of the woodland species pool. Additionally, the role of local depressions with high humidity that were covered by post‐fire alder woods in the colonization process, as well as species survivorship and recolonisation, were estimated. Woodland species showed diverse migration paces among the sites; most of them migrated faster on more fertile sites with a higher humidity. Small patches of post‐fire alder woods contributed to the recolonisation process since many woodland species in the herb layer survived the fire due to its high humidity, which inhibited the intensity of the forest fire. The recovery of woodland species in post‐fire woods is the combined effect of regeneration, which relies on autochthonic propagules, and secondary succession, which is based on allochthonic propagules. Local depressions, which provide refuges for fire‐sensitive, dispersal‐limited species, contribute to their survivorship and thus to the successive recovery of herbaceous layers after a fire.