Showing papers on "Bark published in 2021"

Chemical functional groups of extractives, cellulose and lignin extracted from native Leucaena leucocephala bark

Abstract: Bark from trees is considered a worthless raw material. However, this resource could be economically beneficial if utilized efficiently due to its rich chemical compounds. In this study, an ethanol toluene-soluble extractive, alpha-cellulose and lignin obtained from Leucaena leucocephala bark were characterized to determine their chemical functional groups. Based on FTIR spectral analysis, the results indicated that the bands of the functional groups of the extractive from the original bark remain unchanged; however, the absorbance intensity was found to be weaker in the group frequency and fingerprint regions. Removal of extractive, pectin, hemicellulose and lignin from the bark indirectly increased the strong absorbance intensity of cellulose. Broad peaks of OH stretching found in all spectra were assigned to the presence of phenolic OH and aliphatic structures for extractive and aromatic structures of lignin. It was revealed that aromatic functional groups were mainly found in the extractive, while water, carbonyl and ether were the dominant groups in cellulose, and methyl, methylene, carbonyl and carboxyl groups were enriched in lignin.

Do bark beetle outbreaks amplify or dampen future bark beetle disturbances in Central Europe

Abstract: Bark beetle outbreaks have intensified in many forests around the globe in recent years. Yet, the legacy of these disturbances for future forest development remains unclear. Bark beetle disturbances are expected to increase further because of climate change. Consequently, feedbacks within the disturbance regime are of growing interest, for example, whether bark beetle outbreaks are amplifying future bark beetle activity (through the initiation of an even‐aged cohort of trees) or dampening it (through increased structural and compositional diversity). We studied bark beetle–vegetation–climate interactions in the Bavarian Forest National Park (Germany), an area characterised by unprecedented bark beetle activity in the recent past. We simulated the effect of future bark beetle outbreaks on forest structure and composition and analysed how disturbance‐mediated forest dynamics influence future bark beetle activity under different scenarios of climate change. We used process‐based simulation modelling in combination with machine learning to disentangle the long‐term interactions between vegetation, climate and bark beetles at the landscape scale. Disturbances by the European spruce bark beetle were strongly amplified by climate change, increasing between 59% and 221% compared to reference climate. Bark beetle outbreaks reduced the dominance of Norway spruce (Picea abies (L.) Karst.) on the landscape, increasing compositional diversity. Disturbances decreased structural diversity within stands (α diversity) and increased structural diversity between stands (β diversity). Overall, disturbance‐mediated changes in forest structure and composition dampened future disturbance activity (a reduction of up to −67%), but were not able to fully compensate for the amplifying effect of climate change. Synthesis. Our findings indicate that the recent disturbance episode at the Bavarian Forest National Park was caused by a convergence of highly susceptible forest structures with climatic conditions favourable for bark beetle outbreaks. While future climate is increasingly conducive to massive outbreaks, the emerging landscape structure is less and less likely to support them. This study improves our understanding of the long‐term legacies of ongoing bark beetle disturbances in Central Europe. It indicates that increased diversity provides an important dampening feedback, and suggests that preventing disturbances or homogenizing post‐disturbance forests could elevate the future susceptibility to large‐scale bark beetle outbreaks.

Physical, Chemical, Thermal, and Surface Morphological Properties of the Bark Fiber Extracted from Acacia Concinna Plant

Abstract: This research aimed to assess the fitness of fiber collected from the bark of Acacia concinna (AC) plant for composite reinforcement. Chemical analysis report exposed that ACF has the cellulose and...

Fungal Planet description sheets: 1182–1283

Abstract: Novel species of fungi described in this study include those from various countries as follows: Algeria, Phaeoacremonium adelophialidum from Vitis vinifera. Antarctica, Comoclathris antarctica from soil. Australia, Coniochaeta salicifolia as endophyte from healthy leaves of Geijera salicifolia, Eremothecium peggii in fruit of Citrus australis, Microdochium ratticaudae from stem of Sporobolus natalensis, Neocelosporium corymbiae on stems of Corymbia variegata, Phytophthora kelmanii from rhizosphere soil of Ptilotus pyramidatus, Pseudosydowia backhousiae on living leaves of Backhousia citriodora, Pseudosydowia indooroopillyensis, Pseudosydowia louisecottisiae and Pseudosydowia queenslandica on living leaves of Eucalyptus sp. Brazil, Absidia montepascoalis from soil. Chile, Ilyonectria zarorii from soil under Maytenus boaria. Costa Rica, Colletotrichum filicis from an unidentified fern. Croatia, Mollisia endogranulata on deteriorated hardwood. Czech Republic, Arcopilus navicularis from tea bag with fruit tea, Neosetophoma buxi as endophyte from Buxus sempervirens, Xerochrysium bohemicum on surface of biscuits with chocolate glaze and filled with jam. France, Entoloma cyaneobasale on basic to calcareous soil, Fusarium aconidiale from Triticum aestivum, Fusarium juglandicola from buds of Juglans regia. Germany, Tetraploa endophytica as endophyte from Microthlaspi perfoliatum roots. India, Castanediella ambae on leaves of Mangifera indica, Lactifluus kanadii on soil under Castanopsis sp., Penicillium uttarakhandense from soil. Italy, Penicillium ferraniaense from compost. Namibia, Bezerromyces gobabebensis on leaves of unidentified succulent, Cladosporium stipagrostidicola on leaves of Stipagrostis sp., Cymostachys euphorbiae on leaves of Euphorbia sp., Deniquelata hypolithi from hypolith under a rock, Hysterobrevium walvisbayicola on leaves of unidentified tree, Knufia hypolithi and Knufia walvisbayicola from hypolith under a rock, Lapidomyces stipagrostidicola on leaves of Stipagrostis sp., Nothophaeotheca mirabibensis (incl. Nothophaeotheca gen. nov.) on persistent inflorescence remains of Blepharis obmitrata, Paramyrothecium salvadorae on twigs of Salvadora persica, Preussia procaviicola on dung of Procavia sp., Sordaria equicola on zebra dung, Volutella salvadorae on stems of Salvadora persica. Netherlands, Entoloma ammophilum on sandy soil, Entoloma pseudocruentatum on nutrient poor (acid) soil, Entoloma pudens on plant debris, amongst grasses. New Zealand, Amorocoelophoma neoregeliae from leaf spots of Neoregelia sp., Aquilomyces metrosideri and Septoriella callistemonis from stem discolouration and leaf spots of Metrosideros sp., adophora neoregeliae from leaf spots of Neoregelia sp., Flexuomyces asteliae (incl. Flexuomyces gen. nov.) and Mollisia asteliae from leaf spots of Astelia chathamica, Ophioceras freycinetiae from leaf spots of Freycinetia banksii, Phaeosphaeria caricis-sectae from leaf spots of Carex secta. Norway, Cuphophyllus flavipesoides on soil in semi-natural grassland, Entoloma coracis on soil in calcareous Pinus and Tilia forests, Entoloma cyaneolilacinum on soil semi-natural grasslands, Inocybe norvegica on gravelly soil. Pakistan, Butyriboletus parachinarensis on soil in association with Quercus baloot. Poland, Hyalodendriella bialowiezensis on debris beneath fallen bark of Norway spruce Picea abies. Russia, Bolbitius sibiricus on а moss covered rotting trunk of Populus tremula, Crepidotus wasseri on debris of Populus tremula, Entoloma isborscanum on soil on calcareous grasslands, Entoloma subcoracis on soil in subalpine grasslands, Hydropus lecythiocystis on rotted wood of Betula pendula, Meruliopsis faginea on fallen dead branches of Fagus orientalis, Metschnikowia taurica from fruits of Ziziphus jujube, Suillus praetermissus on soil, Teunia lichenophila as endophyte from Cladonia rangiferina. Slovakia, Hygrocybe fulgens on mowed grassland, Pleuroflammula pannonica from corticated branches of Quercus sp. South Africa, Acrodontium burrowsianum on leaves of unidentified Poaceae, Castanediel a senegaliae on dead pods of Senegalia ataxacantha, Cladophialophora behniae on leaves of Behnia sp., Colletotrichum cliviigenum on leaves of Clivia sp., Diatrype dalbergiae on bark of Dalbergia armata, Falcocladium heteropyxidicola on leaves of Heteropyxis canescens, Lapidomyces aloidendricola as epiphyte on brown stem of Aloidendron dichotomum, Lasionectria sansevieriae and Phaeosphaeriopsis sansevieriae on leaves of Sansevieria hyacinthoides, Lylea dalbergiae on Diatrype dalbergiae on bark of Dalbergia armata, Neochaetothyrina syzygii (incl. Neochaetothyrina gen. nov.) on leaves of Syzygium chordatum, Nothophaeomoniella ekebergiae (incl. Nothophaeomoniella gen. nov.) on leaves of Ekebergia pterophylla, Paracymostachys euphorbiae (incl. Paracymostachys gen. nov.) on leaf litter of Euphorbia ingens, Paramycosphaerella pterocarpi on leaves of Pterocarpus angolensis, Paramycosphaerella syzygii on leaf litter of Syzygium chordatum, Parateichospora phoenicicola (incl. Parateichospora gen. nov.) on leaves of Phoenix reclinata, Seiridium syzygii on twigs of Syzygium chordatum, Setophoma syzygii on leaves of Syzygium sp., Starmerella xylocopis from larval feed of an Afrotropical bee Xylocopa caffra, Teratosphaeria combreti on leaf litter of Combretum kraussii, Teratosphaericola leucadendri on leaves of Leucadendron sp., Toxicocladosporium pterocarpi on pods of Pterocarpus angolensis. Spain, Cortinarius bonachei with Quercus ilex in calcareus soils, Cortinarius brunneovolvatus under Quercus ilex subsp. ballota in calcareous soil, Extremopsis radicicola (incl. Extremopsis gen. nov.) from root-associated soil in a wet heathland, Russula quintanensis on acidic soils, Tubaria vulcanica on volcanic lapilii material, Tuber zambonelliae in calcareus soil. Sweden, Elaphomyces borealis on soil under Pinus sylvestris and Betula pubescens. Tanzania, Curvularia tanzanica on inflorescence of Cyperus aromaticus. Thailand, Simplicillium niveum on Ophiocordyceps camponoti-leonardi on underside of unidentified dicotyledonous leaf. USA, Calonectria californiensis on leaves of Umbellularia californica, Exophiala spartinae from surface sterilised roots of Spartina alterniflora, Neophaeococcomyces oklahomaensis from outside wall of alcohol distillery. Vietnam, Fistulinella aurantioflava on soil. Morphological and culture characteristics are supported by DNA barcodes. © 2021 Naturalis Biodiversity Center & Westerdijk Fungal Biodiversity Institute.

Characteristics of beech bark and its effect on properties of UF adhesive and on bonding strength and formaldehyde emission of plywood panels

Abstract: This research examined beech bark from a plywood manufacturer to determine its effectiveness in reducing wastes, protecting the ecological environment, and producing more eco-friendly wood-based materials. Beech bark was characterized and evaluated as an adhesive filler in plywood manufacturing, and the effects on the bonding quality and the formaldehyde emission of the plywood panels were examined. Plywood panels were made of formulations with urea-formaldehyde (UF) resin filled with three different concentrations of bark flour (BF): 1 wt%, 3 wt%, and 5 wt%. Compared with solid beech wood, beech bark has a higher lignin and extractives content and lower holocellulose content. It was confirmed that the bark absorbs formaldehyde and the solution with 5 wt% of bark absorbed the most formaldehyde. Panels with UF/BF formulations at a bark content of 1 wt%, 3 wt%, and 5 wt% had higher wet bonding strengths than those made with the control sample. The most significant reduction in formaldehyde emission (up to 42.3%) of plywood panels and the achievement of high bonding strength was observed for UF/BF samples with a bark concentration of 5 wt%. The bonding strength of plywood panels with all investigated BF concentrations met the requirements of the EN 314-2 standard.

Bark-dwelling methanotrophic bacteria decrease methane emissions from trees.

Abstract: Tree stems are an important and unconstrained source of methane, yet it is uncertain whether internal microbial controls (i.e. methanotrophy) within tree bark may reduce methane emissions. Here we demonstrate that unique microbial communities dominated by methane-oxidising bacteria (MOB) dwell within bark of Melaleuca quinquenervia, a common, invasive and globally distributed lowland species. In laboratory incubations, methane-inoculated M. quinquenervia bark mediated methane consumption (up to 96.3 µmol m-2 bark d-1) and reveal distinct isotopic δ13C-CH4 enrichment characteristic of MOB. Molecular analysis indicates unique microbial communities reside within the bark, with MOB primarily from the genus Methylomonas comprising up to 25 % of the total microbial community. Methanotroph abundance was linearly correlated to methane uptake rates (R2 = 0.76, p = 0.006). Finally, field-based methane oxidation inhibition experiments demonstrate that bark-dwelling MOB reduce methane emissions by 36 ± 5 %. These multiple complementary lines of evidence indicate that bark-dwelling MOB represent a potentially significant methane sink, and an important frontier for further research.

A Comparative Analysis of Bark and Leaf Essential Oil and their Chemical Composition, Antioxidant, Anti-inflammatory, Antimicrobial Activities and Genotoxicity of North East Indian Cinnamomum zeylanicum Blume

Abstract: Cinnamomum zeylanicum Blume ( Lauraceae) bark and leaf essential oil possesses eugenol as the major component. Both the essential oils have the potential antioxidant, anti- inflammatory, antimicrobial and negligible genotoxicity. A comparative chemical composition and biological evaluation of Cinnamomum zeylanicum Blume, bark and leaf essential oils, originated from North-East India has been investigated in the present study. Gas chromatography/mass spectroscopy analysis was used to investigate the chemical composition of the essential oil samples. DPPH free radical scavenging activity, and reducing power assay were used for antioxidant activity evaluation. Similarly, egg albumin denaturation assay, protease inhibitory activities were used for anti-inflammatory activity, while genotoxicity was evaluated by using Allium cepa assay and antimicrobial activities using disc diffusion and minimum inhibitory concentration assay. The GC/MS results showed that eugenol is the major component of C. zeylanicum bark (84.48%) and leaf (48.78 %) essential oil. Significant antioxidant activity was observed for both essential oils in the DPPH free radical scavenging assay (IC50= 103.2 μg/mL, bark; IC50= 234.7 μg/mL, leaf), and reducing power assay (absorbance of 1.802 nm, 0.907 nm in 48 μg/mL for bark and leaf essential oil respectively). In-vitro anti-inflammatory activity revealed strong potential of leaf essential oil (protein denaturation assay, IC50= 0.05279 μg/mL; protease inhibitory activity IC50= 3.607 μg/mL) in comparison to bark essential oil (protein denaturation assay IC50= 0.1491, protease inhibitory activity IC50= 61.06). Allium cepa root growth test, mitotic index, and chromosomal aberration test were performed to investigate the genotoxicity of C. zeylanicum bark and leaf essential oil, which resulted in no toxic nature of both the essential oils. Antimicrobial activity against eight bacterial and fungal strains revealed good antimicrobial properties with the MIC value of Staphylococcus aureus at 5 μL/mL (bark), Aspergillus niger at 2.5 μL/mL (bark); Bacillus cereus at 5 μL/mL (leaf) and Aspergillus niger at 2.5 μL/mL (leaf). Collectively, these findings indicated the strong biological potential of both essential oils, although bark essential possesses better biological activities than the leaf essential oil and could be used in the food and beverage industries.

Inner bark as a crucial tissue for non‐structural carbohydrate storage across three tropical woody plant communities

Abstract: Non-structural carbohydrates (NSC) are crucial for forest resilience, but little is known regarding the role of bark in NSC storage. However, bark's abundance in woody stems and its large living fraction make it potentially key for NSC storage. We quantified total NSC, soluble sugar (SS) and starch concentrations in the most living region of bark (inner bark, IB), and sapwood of twigs, trunks and roots of 45 woody species from three contrasting tropical climates spanning global extremes of bark diversity and wide phylogenetic diversity. NSC concentrations were similar (total NSC, starch) or higher (SS) in IB than wood, with concentrations co-varying strongly. NSC concentrations varied widely across organs and species within communities and were not significantly affected by climate, leaf habit or the presence of photosynthetic bark. Starch concentration tended to increase with density, but only in wood. IB contributed substantially to NSC storage, accounting for 17-36% of total NSC, 23-47% of SS and 15-33% of starch pools. Further examination of the drivers of variation in IB NSC concentration, and taking into account the substantial contribution of IB to NSC pools, will be crucial to understand the role of storage in plant environmental adaptation.

Heat Stress in Broiler Chickens and the Effect of Dietary Polyphenols, with Special Reference to Willow (Salix spp.) Bark Supplements-A Review.

Abstract: Over the last decade, there has been a growing interest in the use of a wide range of phytoadditives to counteract the harmful effects of heat stress in poultry. Willow (Salix spp.) is a tree with a long history. Among various forms, willow bark is an important natural source of salicin, β-O-glucoside of saligenin, but also of polyphenols (flavonoids and condensed tannins) with antioxidant, antimicrobial, and anti-inflammatory activity. In light of this, the current review presents some literature data aiming to: (1) describe the relationship between heat stress and oxidative stress in broilers, (2) present or summarize literature data on the chemical composition of Salix species, (3) summarize the mechanisms of action of willow bark in heat-stressed broilers, and (4) present different biological effects of the extract of Salix species in different experimental models.

Characterization of the Cellulose Fibers Extracted from the Bark of Piliostigma Racemosa

Abstract: The purpose of this present investigation is to characterize the cellulosic fibers extracted from the bark of Piliostigma racemosa plant to assess the suitability of these fibers for reinforcing po...

Walnut (J. regia) Agro-Residues as a Rich Source of Phenolic Compounds.

Abstract: The present study was designed to identify and quantify the major phenolic compounds (phenolics) in the inner and outer husks, buds and bark of the Persian walnut, Juglans regia L. A comparison across six different cultivars grown in Slovenia was also carried out: ‘Fernor’, ‘Fernette’, ‘Franquette’, ‘Sava’, ‘Krka’ and ‘Rubina’. A total of 83 compounds were identified, which included 25 naphthoquinones, 15 hydroxycinnamic acids, 8 hydroxybenzoic acids, 13 flavanols, 2 flavones, 1 flavanone and 19 flavonols. For the first time, 38 phenolics in the husks, 57 phenolics in the buds and 29 phenolics in the bark were presented in J. regia within this study. Naphthoquinones were the major phenolics determined, approximately 75% of all analysed phenolics in the inner husk, 85% in the outer husk, 50% in buds and 80% in bark. The highest content of phenolics was found in the walnut buds, followed by the bark, the inner husk and the outer husk. On the basis of these high phenolic contents, walnut husks, buds and bark represented valuable by-products of the walnut tree. These data also show origin-related phenolic contents across the cultivars, and thus these phenolic profiles might serve to define the origins of different walnut cultivars.

A fine-scale spatial analysis of fungal communities on tropical tree bark unveils the epiphytic rhizosphere in orchids.

Abstract: Approximately 10% of vascular plants are epiphytes and, even though this has long been ignored in past research, are able to interact with a variety of fungi, including mycorrhizal taxa. However, the structure of fungal communities on bark, as well as their relationship with epiphytic plants, is largely unknown. To fill this gap, we conducted environmental metabarcoding of the ITS-2 region to understand the spatial structure of fungal communities of the bark of tropical trees, with a focus on epiphytic orchid mycorrhizal fungi, and tested the influence of root proximity. For all guilds, including orchid mycorrhizal fungi, fungal communities were more similar when spatially close on bark (i.e. they displayed positive spatial autocorrelation). They also showed distance decay of similarity with respect to epiphytic roots, meaning that their composition on bark increasingly differed, compared to roots, with distance from roots. We first showed that all of the investigated fungal guilds exhibited spatial structure at very small scales. This spatial structure was influenced by the roots of epiphytic plants, suggesting the existence of an epiphytic rhizosphere. Finally, we showed that orchid mycorrhizal fungi were aggregated around them, possibly as a result of reciprocal influence between the mycorrhizal partners.

Hygroscopic contributions to bark water storage and controls exerted by internal bark structure over water vapor absorption

Abstract: Hygroscopicity is a crucial element of bark water storage and can reach >60% of water holding capacity of bark depending on tree species Bark forms the outer layer of woody plants, and it is directly exposed to wetting during rainfall and reacts to changes in relative humidity, i.e., it may exchange water with the atmosphere through absorption and desorption of water vapor. A current paradigm of bark hydrology suggests that the maximum water storage of bark empties between precipitation events and is principally controlled by bark thickness and roughness. We hypothesize that (1) the ability of bark to absorb water vapor during non-rainfall periods (i.e., hygroscopicity) leads to partial saturation of bark tissues during dry periods that may alter the rate of bark saturation during rainfall, and (2) the degree of bark saturation through hygroscopic water is a function of internal bark structure, including porosity and density, that varies among species. To address these questions, we conducted laboratory experiments to measure interspecific differences in bark physical structure as it relates to water storage mechanisms among common tree species (hickory (Carya spp.), oak (Quercus spp.), sweetgum (Liquidambar styraciflua), and loblolly pine (Pinus taeda)) in the southeastern United States. Furthermore, we considered how these properties changed across total bark, outer bark, and inner bark. We found a distinct difference between hickory and oak, whereby hickory had 5.6% lower specific density, 31.1% higher bulk density, and 22.4% lower total porosity of outer bark resulting in higher hygroscopicity compared to oaks. For all species, hygroscopicity increased linearly with bulk density (R2 = 0.65–0.81) and decreased linearly with total porosity (R2 = 0.64–0.88). Overall, bark hygroscopicity may constitute an average of 30% of total bark water storage capacity. Therefore, in humid climates like those of the southeastern USA, the proportion of bark that remains saturated during non-storm conditions should not be considered negligible.

Investigation of Physico Chemical Properties and Characterization of New Natural Cellulosic Fibers from the Bark of Ficus Racemosa

Abstract: The objective of this examination is to characterize the fibers from the bark of Ficus racemosa fibers (FRF). FRF is composed of cellulose (72.36 wt. %), hemicellulose (11.21wt. %), lignin (10.45 w...

Application of design of experiments (DoE) for optimised production of micro- and mesoporous Norway spruce bark activated carbons

Abstract: In this work, Norway spruce (Picea abies (Karst) L.) bark was employed as a precursor to prepare activated carbon using zinc chloride (ZnCl2) as a chemical activator. The purpose of this study was to determine optimal activated carbon (AC) preparation variables by the response surface methodology using a Box–Behnken design (BBD) to obtain AC with high specific surface area (SBET), mesopore surface area (SMESO), and micropore surface area (SMICR). Variables and levels used in the design were pyrolysis temperature (700, 800, and 900 °C), holding time (1, 2, and 3 h), and bark/ZnCl2 impregnation ratio (1, 1.5, and 2). The optimal conditions for achieving the highest SBET were as follows: a pyrolysis temperature of 700 °C, a holding time of 1 h, and a spruce bark/ZnCl2 ratio of 1.5, which yielded an SBET value of 1374 m2 g−1. For maximised mesopore area, the optimal condition was at a pyrolysis temperature of 700 °C, a holding time of 2 h, and a bark/ZnCl2 ratio of 2, which yielded a SMESO area of 1311 m2 g−1, where mesopores (SMESO%) comprised 97.4% of total SBET. Correspondingly, for micropore formation, the highest micropore area was found at a pyrolysis temperature of 800 °C, a holding time of 3 h, and a bark/ZnCl2 ratio of 2, corresponding to 1117 m2 g−1, with 94.3% of the total SBET consisting of micropores (SMICRO%). The bark/ZnCl2 ratio and pyrolysis temperature had the strongest impact on the SBET, while the interaction between temperature and bark/ZnCl2 ratio was the most significant factor for SMESO. For the SMICRO, holding time was the most important factor. In general, the spruce bark AC showed predominantly mesoporous structures. All activated carbons had high carbon and low ash contents. Chemical characterisation indicated that the ACs presented disordered carbon structures with oxygen functional groups on the ACs’ surfaces. Well-developed porosity and a large surface area combined with favourable chemical composition render the activated carbons from Norway spruce bark with interesting physicochemical properties. The ACs were successfully tested to adsorb sodium diclofenac from aqueous solutions showing to be attractive products to use as adsorbents to tackle polluted waters.

Sustaining Medicinal Barks: Survival and Bark Regeneration of Amphipterygium adstringens (Anacardiaceae), a Tropical Tree under Experimental Debarking

Abstract: Commercial harvests can threaten tree species harvested for their bark. Amphipterygium adstringens is a dioecious tree, endemic to the tropical dry forests of Mexico, where it is intensively harvested for its medicinal bark. Limited information hinders developing sustainable management strategies for A. adstringens. We assessed bark regeneration for male and female trees, and evaluated the effect of tree sex and diameter, debarking treatments and cutting seasons on bark regeneration and tree survival rates. Bark regeneration was higher for wet season harvested trees (vs. dry), regardless of their sex. Bark regeneration was higher on female than on male trees. There were significant interactions of harvest season, harvest treatment and tree sex diameter on bark regeneration and survival. Overall, the highest bark regeneration rates occurred in female trees with ≥20.1 cm diameter that were wet season harvested with a 50% debarking intensity. Consequently, wet season and intermediate intensity harvests appear to foster sound management, but we recommend against targeting exclusively a single demographic group (i.e., large female trees) due to potential negative impacts on species demography and bark supply. A grounded strategy for sustaining bark harvest would also need to take into account relevant aspects of local socio-ecological context, including harvest interactions with other land uses.

Extracts from pine and oak barks: phenolics, minerals and antioxidant potential

Abstract: Residues of wood, such as bark, represent an attractive source for natural antioxidants. The aim of this study was to evaluate the total polyphenols, heavy metals content and antioxidant capacity f...

Comparative Study Regarding the Chemical Composition and Biological Activity of Pine (Pinus nigra and P. sylvestris) Bark Extracts

Abstract: The bark resulted after the industrial processing of wood represents a byproduct of the forestry industry, used in many suboptimal ways, being considered a natural waste. Currently, it has been highlighted that the bark of different woody plants may be an important source of several bioactive compounds, with various beneficial biological functions. The aim of this study is to evaluate and compare the chemical composition and biological activities of two different pine species (Pinus nigra and Pinus sylvestris) bark extracts. Ultrasound (UAE) and microwave (MAE) assisted extractions were performed in order to obtain the extracts. The total polyphenol (TPC) and total tannin (TTC) contents of the extracts were assessed via the Folin–Ciocâlteu method. The volatile and polyphenolic compounds were identified and quantified via a GC/MS analysis and an UPLC-PDA analysis, respectively. The antioxidant activity (AOA) was evaluated using the DPPH and ABTS assays, while the antibacterial activity was assessed using the minimum inhibitory concentration (MIC) protocol. The results showed that the Pinus sylvestris bark extracts obtained by UAE had a higher TPC, TTC and AOA, while the Pinus nigra bark extracts obtained by MAE had higher volatile compounds content (mainly α-pinene and β-pinene). Moreover, the inhibition of the bacterial growth was more efficient in the case of Pinus sylvestris extracts, Gram-positive bacteria being the most affected, while Gram-negative strains presented a relative resistance to the tested extract concentrations. These results may indicate the potential use of the pine bark extracts as antioxidant or antibacterial agents.

Binderless Thermal Insulation Panels Made of Spruce Bark Fibres.

Abstract: Tree bark is a by-product of the timber industry available in large amounts, considering that approximately 10% of the volume of a tree stem is bark. Bark is used primarily for low-value applications such as heat generation or as mulch. To the best of our knowledge, this study is the first one that scrutinises thermal insulation panels made from spruce bark fibres with different densities and fibre lengths manufactured in a wet process. The insulation boards with densities between 160 and 300 kg/m3 were self-bonded. Internal bond, thermal conductivity, and dimensional stability (thickness swelling and water absorption), together with formaldehyde content, were analysed. The thermal properties of the boards were directly correlated with the density and reached about 0.044 W/m*K, while the internal bond was rather influenced by the fibre length and was relatively low (on average 0.07 N/mm2). The water absorption was high (from 55% to 380%), while the thickness swelling remained moderate (up to 23%). The results of this study have shown that widely available bark residues can be successfully utilised as an innovative raw material for efficient eco-friendly thermal insulation products.

Combined drought and bark beetle attacks deplete non-structural carbohydrates and promote death of mature pine trees

Abstract: How carbohydrate reserves in conifers respond to drought and bark beetle attacks are poorly understood. We investigated changes in carbohydrate reserves and carbon-dependent diterpene defences in ponderosa pine trees that were experimentally subjected to two levels of drought stress (via root trenching) and two types of biotic challenge treatments (pheromone-induced bark beetle attacks or inoculations with crushed beetles that include beetle-associated fungi) for two consecutive years. Our results showed that trenching did not influence carbohydrates, whereas both biotic challenges reduced amounts of starch and sugars of trees. However, only the combined trenched-bark beetle attacked trees depleted carbohydrates and died during the first year of attacks. While live trees contained higher carbohydrates than dying trees, amounts of constitutive and induced diterpenes produced did not vary between live and beetle-attacked dying trees, respectively. Based on these results we propose that reallocation of carbohydrates to diterpenes during the early stages of beetle attacks is limited in drought-stricken trees, and that the combination of biotic and abiotic stress leads to tree death. The process of tree death is subsequently aggravated by beetle girdling of phloem, occlusion of vascular tissue by bark beetle-vectored fungi, and potential exploitation of host carbohydrates by bark beetle symbionts as nutrients.

Influence of storage on the physical and chemical properties of Scots pine bark

Abstract: Bark is currently used mainly to produce energy, but the extraction of valuable compounds before combustion offers an interesting cascading use for debarking biomass. Buffer storage is an inevitable part of bark biomass logistics, but substantial dry matter and extractive losses can degrade the properties and reduce the economic value of the raw material during storage. In this study, moisture and ash content, calorific value, and extractives content and composition of Scots pine (Pinus sylvestris) sawmill bark were determined over 2 months of buffer storage, and the change in energy content during storage was calculated. The results showed that the energy content (MWh m−3) of the bark increased 3% during storage, while at the same time the moisture content decreased 16%. The content of acetone-soluble extractives decreased markedly, with only 56% of the original amount remaining after 8 weeks of storage. In particular, hydrophilic, phenolic extractive compounds were rapidly lost after debarking and piling of the bark. About 60% of condensed tannins (CT) and about 26% of the quantified lipophilic compounds were lost after 2 weeks of storage. The fastest rate of decrease and the most significant changes in extractives content and composition occurred within the first 2 weeks of storage. Utilization of these valuable compounds necessitates fast supply of material for further processing after debarking. The comprehensive utilization of bark requires efficiency at all levels of the supply chain to ensure that tree delivery times are kept short and loss of bark is avoided during harvest and transport.

Effective removal of tetracycline from aqueous solution using biochar prepared from pine bark: isotherms, kinetics and thermodynamic analyses

Abstract: In recent years, there are many concerns about the potential risks of contamination of emerging compounds in water resources and their adverse effects on human health and the environment. Today, th...