Larch Bark Research Articles

Larch (Larix decidua) bark insulation board: interactions of particle orientation, physical\u2013mechanical and thermal properties

The current trend for sustainable utilisation of limited resources is stimulating the scientific research for previously neglected raw materials that could also be used for new value added products. Bark, which is a natural insulation material of trees, could be used as technical insulation material. This paper focuses on the effects of particle orientation in light larch (Larix decidua) bark insulation boards on their physical–mechanical and thermal properties. The experimental design is based on the variation of the particle orientation (orthogonal or parallel to the panel plane) and the board density (200–500 kg/m3). The mechanical properties, water absorption, thickness swelling and thermal conductivity of the boards were tested. The results showed a significant influence of the particle orientation and the density on the measured properties of the bark panels. This implies that the bark particle orientation is an important factor when producing insulation panels with specific characteristics. Suggestions for efficient use of bark particleboard are given.

Reducing copper use in the environment: the use of larixol and larixyl acetate to treat downy mildew caused by Plasmopara viticola in viticulture.

Plant extracts might provide sustainable alternatives to copper fungicides, which are still widely used despite their unfavourable ecotoxicological profile. Larch bark extract and its constituents, larixyl acetate and larixol, have been shown to be effective against grapevine downy mildew (Plasmopara viticola) under semi-controlled conditions. The aim of this study was to reduce the gap between innovation and the registration of a marketable product, namely to develop scalable extraction processes and to evaluate and optimise the performance of larch extracts under different conditions. Toxicologically and technically acceptable solvents like ethanol were used to extract the active compounds larixyl acetate and larixol from bark in sufficient amounts and their combined concentration could be increased by up to 39% by purification steps. The combined concentration of larixyl acetate and larixol from larch turpentine could be increased by up to 66%. The Minimal Inhibitory Concentration (MIC100 ) against P. viticola in vitro (6-23 µg mL-1 ) and the Effective Concentration (EC50 ) in planta under semi-controlled conditions (0.2-0.4 mg mL-1 ) were promising compared with other plant extracts. In vineyards, efficacies of larch extracts reached up to 68% in a stand-alone strategy and 84% in low-copper strategies. Larch extracts represent valid candidates for copper reduction in organic vineyards, and their development into a sustainable plant protection product might be feasible. © 2017 Society of Chemical Industry.

Larix decidua Bark as a Source of Phytoconstituents: An LC-MS Study.

Larix decidua bark is a waste of the timber industry and is widely diffused in Northern Italy. This material can be considered a good source of antioxidants and phytoconstituents with possible use in cosmetic or nutraceutical products. In this study, simple extraction of larch bark was performed using mixtures of ethanol/water. Furthermore, the phytochemical composition of larch bark extract was studied using LC-MSn methods and the main constituents were identified as flavonoids, spiro-polyphenols, and procyanidins. To confirm the identification by LC-MS semi-preparative HPLC was performed in order to isolate the main constituents and verify the structures by 1H-NMR. Antioxidant properties were studied using an in vitro approach combining DPPH assay and LC-MS in order to establish different roles of the various classes of phytochemicasl of the extract. DPPH activity of some of the isolated compounds was also assessed. The overall results indicate this waste material as a good source of antioxidant compounds, mainly procyanidins, whichresulted the most active constituents in the DPPH assay.

Climate-growth relationships and pointer year analysis of a Siberian larch (Larix sibirica Ledeb.) chronology from the Mongolian mountain forest steppe compared to white birch (Betula platyphylla Sukaczev)

BackgroundForest area, stand quality and growth of Siberian larch in Mongolia have decreased significantly over recent decades. This forest decline is frequently attributed to factors such as unregulated logging, increased ecological disturbances (primarily fire) and climate change. In this study, we analyzed climate-growth response and pointer years for Siberian larch observed in the Altansumber forest research area in the Mongolian mountain forest steppe zone. We compare our results with previously published results of white birch from the same area.MethodsWe built a reference chronology from wood core samples taken from 30 trees in three neighboring larch stands. Climate-growth relationships were analyzed monthly and seasonally over the period 1962–2009 using climate data from the Eroo weather station. Pointer year analysis covered the same time frame.ResultsOur analysis of the larch chronology showed that precipitation during autumn of the previous year and directly before the growing season of the current year was the most decisive factor determining tree-ring growth. Regional pointer year analysis further indicated that a humid summer and autumn followed by a warm spring support current-year tree-ring growth in these larch stands. Our findings were comparable to a white birch study in the same area. The larch trees, however, showed stronger growth performance and were more tolerant of higher temperatures, notably in spring during peak fire season.ConclusionsWater availability is the decisive factor for larch growth in the mountain forest steppe zone. The chronologies showed no climatic indication of insect infestations. Differences in climate-growth relationships of birch and larch trees during peak fire season may to some degree be explained by their respective means of protecting themselves against low-intensity surface fires (e.g. thick bark of larch). These fire events occur regularly in the region and are influenced by climatic factors. Our analysis and comparison of climate tree-growth relationships may be valuable for developing climate- and disturbance-resilient forestry practices in Mongolian mountain forest ecosystems.

Pest categorisation of Ipscembrae.

The Panel on Plant Health performed a pest categorisation of the large larch bark beetle, Ips cembrae (Heer) (Coleoptera: Curculionidae, Scolytinae), for the EU. I. cembrae is a well‐defined and distinguishable species, native to Europe and recognised mainly as a pest of larch (Larix spp.) and occasionally of pine (Pinus spp.) and spruce (Picea spp.). It is distributed in 16 Member States of the EU and listed in Annex IIB of Council Directive 2000/29/EC. Protected zones are in place in Greece, Ireland and the United Kingdom (Northern Ireland and Isle of Man). Wood, wood products, bark and wood packaging material are considered as pathways for this pest, which is also able to disperse by flight. The insects normally establish on fallen or weakened trees but, when their populations are high, can also mass‐attack healthy trees. The males produce aggregation pheromones that attract conspecifics of both sexes. The insects also inoculate pathogenic fungi to their hosts. There are one to two generations per year. Before establishing their broods, the young adults need to proceed to maturation feeding either within the bark of the tree where they developed or in 2–18 years old twigs. I. cembrae has been expanding its geographical range in Europe during the second half of the 20th century. Sanitary thinning or clear felling is the major control methods. Quarantine measures are implemented to prevent entry in the protected zones. All criteria for consideration as potential protected zone quarantine pest are met. The criteria for considering I. cembrae as a potential regulated non‐quarantine pest are not met since plants for planting are not viewed as a major pathway.

Sustainability of denitrifying bioreactors with various fill media

Nitrogen losses from utilised agricultural areas are responsible for water quality degradation and eutrophication. Denitrifying bioreactors can be used to reduce high nitrate concentrations in agricultural runoff in situ. The main factors affecting their function are the bioreactor fill medium and process parameters such as hydraulic retention time, temperature and inlet concentration of nitrates. The paper presents the results of laboratory experiments achieved with bioreactors filled with eight different wood-based materials, namely mulch, a mixture of spruce and pine sawdust, a mixture of pine and larch bark, and chips made of oak, poplar, larch, beech, and spruce wood. A sustainability index was used to assess the impact of the bioreactor on the environment. The best results were shown by beech, mulch and poplar and were achieved with hydraulic retention times 1.6–0.7–2.2 days, respectively, and inlet NO<sub>3</sub><sup>–</sup>-N concentration of 43.1 mg/L.

INVESTIGATION OF SORPTION AND THERAPY-PROPHYLACTICS PROPERTIES OF THE ENTEROSORBENT FROM A LARCH BARK

The sorption capacity of enterosorbent from a larch bark for marker substances modeling the different toxins kinds - methylene blue and gelatine – was investigated. Influence of values pH of model solutions and background electrolyte (0,9 mass % NaCl) addition on the methylene blue and gelatine sorption by enterosorben were investigated. It was shown that designed enterosorbent are able sorb the marker substances from solutions modeling of the stomach and intestine environment conditions. Investigated enterosorbent show the highest efficiency at model conditions of intestine environment. It was shown that enterosorbent from a larch bark exceed commercial enterosorbents on based of hydrolyzed lignin «Polyphepan» in its capacity to sorb the marker substances. On the biological models was determined that the designed enterosorbent show the therapy-prophylactics properties to gastrointestinal infections - escherichiosis. As a result of the bacteriological investigations was determined that the quantity of pathogenic culture E.coli increased 50 times at enterosorbent using in the experimental therapy group, in the prophylactics therapy group – 25 times. The obtained results indicate that the designed enterosorbent from a larch bark have good perspectives for application in veterinary practice.

Added-value for wood bark as a coating layer for flooring tiles

Worldwide more than 50% of the bark amount is used for energy generation. In this research, physico-mechanical and surface properties of flooring tiles coated with thin layers made of larch bark are presented for the first time. Two types of adhesives were involved to bond the bark particles, namely polyurethane and a formaldehyde-free tannin-hexamine resin.Larch (Larix decidua Mill.) bark was used to produce layers with 3 mm thickness at three levels of density, from 0.6 to 0.8 g/cm³, to coat standard high density fiberboard (HDF) as core material. Mechanical and physical properties of the specimens including surface soundness, Brinell hardness, dimensional stability, abrasion resistance, cross-cut test, resistance to chemicals and fire resistance of the bark coated panels were determined and compared with the properties of industrial multilayered boards with granulated cork as wear layer. Overall, excepting the Brinell hardness, all the properties of the boards produced with wear layer made of larch bark were lower compared to cork-based coated control. Surface soundness of panels with larch wear layer was 30% or 60% lower compared to control. Both thickness swelling and water absorption after 24 h of the panels were too high. Neither polyurethane nor formaldehyde-free tannin adhesive influenced better the panel's properties. Surface properties were similar to control. Although mechanical properties of the samples considered in this work were inferior to those of typical flooring material coated with cork layer, it can be stated that such a little used material like bark may have a useful potential as a value-added product for such application.

Влияние лигнина на свойства органических и углеродных гелей из полифенолов коры лиственницы

Влияние лигнина на свойства органических и углеродных гелей из полифенолов коры лиственницы

Application of tree biochar in PDMS pervaporation membranes

AbstractIn this study, three kinds of biomass materials (lodgepole pine bark, larch wood, larch bark) were used to prepare biochar (BB), and the prepared products as fillers were mixed with polydimethylsiloxane (PDMS) for preparing composite membranes which were used for separating ethanol from water by pervaporation (PV). In accordance with the experiment results, the lodgepole pine bark BB was the best filler for the selective membrane to ethanol. The silane coupling agents NH2(CH2)3Si(OC2H5)3 (KH‐550) and CH2=CH‐Si(OCH3)3 (YDH‐171) were applied in the modification of lodgepole pine bark BB. And the separation performances of the BB/PDMS composite membranes were researched in detail. The results showed that the permeability (flux and separation factor) of composite membranes has been significantly improved with the addition of modified BB. YDH‐171 was more effective than KH‐550. The optimum PV performances (the separation factor 11.3 and the corresponding flux 227.25 g m−2 h−1) were obtained by adding 3 wt. % modified BB for a 10 wt. % and 40°C ethanol solution. This study indicated the potential application of BB nanoparticles in preparing pervaporation separation membrane.

POLYPHENOLS OF WOODY BARK – ORGANIC PRECURSORS TO PRODUCE ON THEIR BASIS OF POLYMER AEROGELS

New method for preparation of organic aerogels by sol-gel polymerization of formaldehyde with polyphenols (PFs), isolated from larch bark of and inner birch bark, was developed. The functional composition and properties of the original PFs were studied by thermogravimetry methods and FTIR- spectroscopy. It was found that larch polyphenol substances possess greater thermal stability in the temperature range 25-700 °C, while the process of thermal decomposition of birch bark polyphenols completes to 600 °C. It has been established that polyphenol larch compounds in their composition contain more aromatic structures and hydroxyl groups. The effect of the pH value of gelation solutions in the range of values from 4 to 12 on the porous structure of organic gels synthesized on the basis of polyphenols was studied. Porous structures and adsorption properties of polyphenol-formaldehyde organic gels were studied using BET method, scanning electron microscopy and sorption (methylene blue and gelatin). It is shown that an increase in pH contributes to the formation of a product with a more compacted texture. The electron microscopic images of polymer gels demonstrate a uniform granular texture with visible micro globules with an average particle size of ≈ 50-70 nm.

Adsorption of Chromium (VI) on Calcium Phosphate: Mechanisms and Stability Constants of Surface Complexes

The adsorption of chromate on octacalcium phosphate (OCP) was investigated as a function of contact time, surface coverage, and solution pH [...]

Characterization and acid-catalysed depolymerization of condensed tannins derived from larch bark

Condensed tannins from larch bark extracts are a natural renewable and eco-friendly material and are potential substitutes for phenolic petrochemicals.

Comparison of phoretic mites associated with bark beetles Ips typographus and Ips cembrae from central Croatia

Na nekoliko lokacija u Hrvatskoj (Nova Gradiška, Koprivnica, Gospić i Jastrebarsko) sa različitih vrsta drveća (Picea abies, Larix decidua i Pinus sylvestris) sakupljani su različiti stadiji ariševog potkornjaka, Ips cembrae i smrekinog pisara, Ips typographus te supstrat iz njihovih hodnika u svrhu sakupljana i identifikacije foretičkih grinja. Izravno sa tijela potkornjaka determinirano je 4 vrsta grinja: Iponemus gaebleri (Tarsenomidae), Histiostoma piceae (Astigmata, Histiostomatoidea), Dendrolaelaps quadrisetus (Gamasina) i Urobovella sp. (Uropodidae). Iponemus gaebleri bila je najčešća nađena vrsta kod obiju vrsta potkornjaka. Tri druge vtrste sakupljene su izravno iz hodničkih sustava. Istraživana su i mjesta spajanja foretičkih grinja s potkornjacima. Iponemus gaebleri i D. quadrisetus tako se najčešće nalaze na obronku zadka, dok se foretičke deutonimfe porodice Histiostomatidae obično nalaze na ventralnoj strani prsišta. Statističkom anlizom potvrđen je jasna preferencija I. gaebleri na I. cembrae. Mladi još nezreli kukci Ips cembrae, koji izlaze iz materinjih hodnika nose signifikantno više foretičkih grinja nego roditeljski. Ženke neidentifcirane vrste roda Histiostoma nađene su u hodnicima I. typographus. Grinje su uglavnom bile pokrivene s većim brojem neidentificiranim sporama gljiva iz skupine Ascomycota (Hypocreales). U radu se daje dihotomski ključ za identifikaciju larvi i protonimfi za porodicu Histiostomatidae.

Особенности парогазовой активации в реакторе с псевдоожиженным слоем коры лиственницы и твердых остатков ее экстракционной переработки

Особенности парогазовой активации в реакторе с псевдоожиженным слоем коры лиственницы и твердых остатков ее экстракционной переработки

Taxonomy and pathogenicity of Leptographium species associated with Ips subelongatus infestations of Larix spp. in northern China, including two new species

The larch bark beetle (Ips subelongatus), which occurs in larch plantations over a vast area of eastern Asia, infects both dying and fallen trees. When its population reaches a high density, the beetle may also infect healthy trees, resulting in tree decline and, eventually, death. Leptographium spp., in both their sexual and asexual states, are mainly associated with conifer-infesting bark beetles; some species are important tree pathogens. The aims of this study were to identify the Leptographium spp. associated with I. subelongatus infestations of Larix spp. in northern China and to examine their pathogenicity towards the tree. Morphological studies and phylogenetic approaches based on multilocus DNA sequence data (ITS2- partial r28S, partial β-tubulin, and EF-1α gene regions) showed that three Leptographium species occur in association with I. subelongatus in the areas investigated: Leptographium taigense, which is recorded in China for the first time, and two new species, namely L. innermongolicum sp. nov. and L. zhangii sp. nov. Leptographium innermongolicum is closely related to L. taigense, whereas L. zhangii belongs to the Grosmannia piceaperda species complex. The pathogenicity of these Leptographium species towards mature Larix spp. was tested by stem inoculation in forests. All inoculations only resulted in small lesions on the inner bark; therefore, the three Leptographium species were not considered to be pathogenic.

Temperature‐dependent development of the European larch bark beetle, Ips cembrae

AbstractThe temperature‐dependent development of the European larch bark beetle, Ips cembrae, was studied under long‐day conditions L:D 16:8 at three temperature regimes, 15°C, 20°C and 25°C, using the sandwich plate method. By observing the individual developmental progress, we calculated the developmental times and lower developmental thresholds of one entire generation and various ontogenetic stages. The mean developmental time of one generation was about 120, 64 and 37 days at 15°C, 20°C and 25°C, respectively. The egg stage comprised about 9% of the total development or about 16% of the pre‐imaginal development. The larval stages took about 39% of the entire and about 66% of the pre‐imaginal development. The pupal stage needed about 11% of the total or about 18% of the pre‐imaginal development. The lower developmental threshold for one generation was 11.2°C. The egg stage had the highest lower developmental threshold of 12.0°C, the pupa the lowest of 9.8°C and the total larval stages showed a value of 11.2°C. The thermal requirements for I. cembrae have never been studied in detail before. The results will be a valuable contribution for monitoring and risk assessment models to estimate the beetle's phenology and its potential impacts on forest ecosystems under changing climate conditions.

Повышение прочности углеродных сорбентов из экстрагированной коры лиственницы путем использования добавок нефтебитума

Повышение прочности углеродных сорбентов из экстрагированной коры лиственницы путем использования добавок нефтебитума

Evaluation of relationships between particle orientation and thermal conductivity in bark insulation board by means of CT and discrete modeling

Insulation boards made out of larch bark were pressed and scanned with an industrial X-ray computed tomograph (CT) in order to study the structure of the boards and to allow structure-based thermal modeling. The CT images were segmented using a categorization algorithm based on ANOVA. Apart from gaining knowledge about panel porosity, understanding of the inhomogeneous bark boards was enhanced by finding that two main components are prevalent. That knowledge of the board's inner microstructure enabled the application of a numerical model for thermal conductivity based on the finite difference method (FDM). Contrary to simple cut-ups, the application of CT and subsequent modeling enables the evaluation of the effects of particle orientation on a panel's thermal conductivity. Panels with horizontal particles (oriented parallel to the panel plane) proved to have a significantly lower thermal conductivity than panels with vertical particles (oriented orthogonal to the panel plane). This trend could be confirmed by means of the presented modeling approach, which allows further theoretical ex ante optimization in the production process. These findings give the direction for developments of efficient bark insulation panels with well-defined microstructure.

Сорбция нефтепродуктов углеродными сорбентами из коры лиственницы сибирской

The adsorption capacity for oil products of granulated sorbents prepared by preliminary carbo-nized larch bark activation with water steam in a fluidized bed was studied. The effect of temper-ature and time of carbonized bark activation on the oil sorption capacity of obtained sorbents was investigated. It has been shown that the increase the temperature of activation from 750 °C to 850 °C and the time of treatment from 30 minutes to 90 minutes leads to the increase of the oil static sorption capacity. The maximum oil capacity (6.8 g/g) was achieved for the sorbent with a grain size of 1-2 mm which was prepared by activation of carbonized bark at 850 °C during 30 minutes.