Showing papers on "Bark published in 2016"

Recent Tree Mortality in the Western United States from Bark Beetles and Forest Fires

Abstract: Forests are substantially influenced by disturbances, and therefore accurate information about the location, timing, and magnitude of disturbances is important for understanding effects. In the western United States, the two major disturbance agents that kill trees are wildfire and bark beetle outbreaks. Our objective was to quantify mortality area (canopy area of killed trees), which better represents impacts than affected area (by beetles) or burn perimeter area, and characterize patterns in space and time. We based our estimates on aerial surveys for bark beetles and the Monitoring Trends in Burn Severity database (from satellite imagery) for fires. We found that during the last three decades, bark beetle-caused mortality area was 6.6 Mha (range of estimates, 0.64 –7.8 Mha; 7.1% [0.7– 8.4%] of the forested area in the western United States) and fire-caused mortality area was 2.7–5.9 Mha (2.9 – 6.3%). Mortality area from beetles and fire was similar to recent harvest area from a national report. Although large outbreaks and fires occurred before 2000, substantially more trees were killed since then. In several forest types, mortality area exceeded 20% of the total forest type area. Our mortality area estimates allow for comparisons among disturbance types and improved assessment of the effects of tree mortality.

Bark thickness across the angiosperms: more than just fire.

Abstract: Global variation in total bark thickness (TBT) is traditionally attributed to fire. However, bark is multifunctional, as reflected by its inner living and outer dead regions, meaning that, in addition to fire protection, other factors probably contribute to TBT variation. To address how fire, climate, and plant size contribute to variation in TBT, inner bark thickness (IBT) and outer bark thickness (OBT), I sampled 640 species spanning all major angiosperm clades and 18 sites with contrasting precipitation, temperature, and fire regime. Stem size was by far the main driver of variation in thickness, with environment being less important. IBT was closely correlated with stem diameter, probably for metabolic reasons, and, controlling for size, was thicker in drier and hotter environments, even fire-free ones, probably reflecting its water and photosynthate storage role. OBT was less closely correlated with size, and was thicker in drier, seasonal sites experiencing frequent fires. IBT and OBT covaried loosely and both contributed to overall TBT variation. Thickness variation was higher within than across sites and was evolutionarily labile. Given high within-site diversity and the multiple selective factors acting on TBT, continued study of the different drivers of variation in bark thickness is crucial to understand bark ecology.

The Utilization of Tree Bark

Abstract: The utilization of natural raw materials has been practiced for centuries. Of raw materials, wood and its bark have outstanding significance because of their special chemical components and unusual structure. Annual bark production is estimated to be between 300 and 400 million m3. The bark of different tree species has been used extensively in or in conjunction with modern technologies. This article presents a comprehensive summary of these methods of utilization and their results. The diversity of bark utilization derives from the variety of the bark of different species and from the possibilities encoded in the material. Following the anatomic summary, the protective role of the bark is discussed, highlighting its physical-chemical properties and the different methods of medical, energetic, and industrial utilization.

Bark water uptake promotes localized hydraulic recovery in coastal redwood crown.

Abstract: Coastal redwood (Sequoia sempervirens), the world's tallest tree species, rehydrates leaves via foliar water uptake during fog/rain events. Here we examine if bark also permits water uptake in redwood branches, exploring potential flow mechanisms and biological significance. Using isotopic labelling and microCT imaging, we observed that water entered the xylem via bark and reduced tracheid embolization. Moreover, prolonged bark wetting (16 h) partially restored xylem hydraulic conductivity in isolated branch segments and whole branches. Partial hydraulic recovery coincided with an increase in branch water potential from about -5.5 ± 0.4 to -4.2 ± 0.3 MPa, suggesting localized recovery and possibly hydraulic isolation. As bark water uptake rate correlated with xylem osmotic potential (R(2) = 0.88), we suspect a symplastic role in transferring water from bark to xylem. Using historical weather data from typical redwood habitat, we estimated that bark and leaves are wet more than 1000 h per year on average, with over 30 events being sufficiently long (>24 h) to allow for bark-assisted hydraulic recovery. The capacity to uptake biologically meaningful volumes of water via bark and leaves for localized hydraulic recovery throughout the crown during rain/fog events might be physiologically advantageous, allowing for relatively constant transpiration.

The bark-beetle-associated fungus, Endoconidiophora polonica, utilizes the phenolic defense compounds of its host as a carbon source

Abstract: Norway spruce (Picea abies) is periodically attacked by the bark beetle Ips typographus and its fungal associate, Endoconidiophora polonica, whose infection is thought to be required for successful beetle attack. Norway spruce produces terpenoid resins and phenolics in response to fungal and bark beetle invasion. However, how the fungal associate copes with these chemical defenses is still unclear. In this study, we investigated changes in the phenolic content of Norway spruce bark upon E. polonica infection and the biochemical factors mediating these changes. Although genes encoding the rate-limiting enzymes in Norway spruce stilbene and flavonoid biosynthesis were actively transcribed during fungal infection, there was a significant time-dependent decline of the corresponding metabolites in fungal lesions. In vitro feeding experiments with pure phenolics revealed that E. polonica transforms both stilbenes and flavonoids to muconoid-type ring-cleavage products, which are likely the first steps in the degradation of spruce defenses to substrates that can enter the tricarboxylic acid cycle. Four genes were identified in E. polonica that encode catechol dioxygenases carrying out these reactions. These enzymes catalyze the cleavage of phenolic rings with a vicinal dihydroxyl group to muconoid products accepting a wide range of Norway spruce-produced phenolics as substrates. The expression of these genes and E. polonica utilization of the most abundant spruce phenolics as carbon sources both correlated positively with fungal virulence in several strains. Thus, the pathways for the degradation of phenolic compounds in E. polonica, initiated by catechol dioxygenase action, are important to the infection, growth, and survival of this bark beetle-vectored fungus and may play a major role in the ability of I. typographus to colonize spruce trees.

Why Be a Shrub? A Basic Model and Hypotheses for the Adaptive Values of a Common Growth Form

Abstract: Shrubs are multi-stemmed short woody plants, more widespread than trees, important in many ecosystems, neglected in ecology compared to herbs and trees, but currently in focus due to their global expansion. We present a novel model based on scaling relationships and four hypotheses to explain the adaptive significance of shrubs, including a review of the literature with a test of one hypothesis. Our model describes advantages for a small shrub compared to a small tree with the same above-ground woody volume, based on larger cross-sectional stem area, larger area of photosynthetic tissue in bark and stem, larger vascular cambium area, larger epidermis (bark) area and larger area for sprouting, and faster production of twigs and canopy. These components form our Hypothesis 1 that predicts higher growth rate for a small shrub than a small tree. This prediction was supported by available relevant empirical studies (14 publications). Further, a shrub will produce seeds faster than a tree (Hypothesis 2), multiple stems in shrubs insure future survival and growth if one or more stems die (Hypothesis 3), and four structural traits of short shrub stems improve survival compared to tall tree stems (Hypothesis 4) – all hypotheses have some empirical support. Multi-stemmed trees may be distinguished from shrubs by more upright stems, reducing bending moment. Improved understanding of shrubs can clarify their recent expansion on savannas, grasslands, and alpine heaths. More experiments and other empirical studies, followed by more elaborate models, are needed to understand why the shrub growth form is successful in many habitats.

Volatile Organic Compounds Emitted by Fungal Associates of Conifer Bark Beetles and their Potential in Bark Beetle Control

Abstract: Conifer bark beetles attack and kill mature spruce and pine trees, especially during hot and dry conditions. These beetles are closely associated with ophiostomatoid fungi of the Ascomycetes, including the genera Ophiostoma, Grosmannia, and Endoconidiophora, which enhance beetle success by improving nutrition and modifying their substrate, but also have negative impacts on beetles by attracting predators and parasites. A survey of the literature and our own data revealed that ophiostomatoid fungi emit a variety of volatile organic compounds under laboratory conditions including fusel alcohols, terpenoids, aromatic compounds, and aliphatic alcohols. Many of these compounds already have been shown to elicit behavioral responses from bark beetles, functioning as attractants or repellents, often as synergists to compounds currently used in bark beetle control. Thus, these compounds could serve as valuable new agents for bark beetle management. However, bark beetle associations with fungi are very complex. Beetle behavior varies with the species of fungus, the stage of the beetle life cycle, the host tree quality, and probably with changes in the emission rate of fungal volatiles. Additional research on bark beetles and their symbiotic associates is necessary before the basic significance of ophiostomatoid fungal volatiles can be understood and their applied potential realized.

Heavy metals content, phytochemical composition, antimicrobial and insecticidal evaluation of Elaeagnus angustifolia:

Abstract: Elaeagnus angustifolia was analyzed for determination of metals, phytoconstituents, bactericidal, fungicidal and insecticidal effects and to explore its chemical and biological potential. The root, branches, leaves, stem bark and root bark parts of E. angustifolia were found to contain iron, lead, copper, cadmium, zinc, chromium, nickel and cobalt in different concentrations. Crude extract of Elaeagnus angustifolia (Ea.Cr) was tested positive for the presence of alkaloids, flavonoids, saponins and tannins. Ea.Cr and its fractions, n-hexane (Ea.Hex), ethyl acetate (Ea.EtAc) and aqueous (Ea.Aq) showed bactericidal activity against Escherichia coli and Staphylococcus aureus, while against Pseudomonas aeruginosa only Ea.Hex and Ea.EtAc were effective. When tested for antifungal effect, Ea.Cr exhibited fungicidal action against Aspergillus fumagatus, Ea.EtAc and Ea.Aq against Aspergillus flavis and Ea.EtAc against Aspergillus niger. Ea.Hex was active against all three fungal strains. The chloroform fraction (E...

Paulownia as a Medicinal Tree: Traditional Uses and Current Advances

Abstract: Paulownia is one of the most useful and sought after trees, in China and elsewhere, due to its multipurpose status. Though not regarded as a regular medicinal plant species, various plant parts (leaves, flowers, fruits, wood, bark, roots and seeds) of Paulownia have been used for treating a variety of ailments and diseases. Each of these parts has been shown to contain one or more bioactive components, such as ursolic acid and matteucinol in the leaves; paulownin and dsesamin in the wood/xylem; syringin and catalpinoside in the bark. The fruits contain fatty oils, alkaloids, flavonones as well as flavonoids with antioxidant properties. The flavonoid contents and TROLOX Equivalent Antioxidant Capacity (TEAC) value in fresh and dry leaf extracts of Paulownia elongata suggest that this species has potential for advanced medicinal use. In vitro grown Paulownia fortunei Hemsl. seedlings, inoculated with Agrobacterium rhizogenes have a potential to produce hairy roots and synthesize bioactive compounds such as acteosides (verbascosides). With various new studies describing isolation of therapeutic compounds and their probable application in human health, it is an opportune moment to revisit medicinal potential of this tree. In this review, the Mini-review Article He et al.; EJMP, 14(1): 1-15, 2016; Article no.EJMP.25170 2 usage of Paulownia in traditional medicine has been revisited and current advances in various fields of research in the genus Paulownia are summarized.

In vitro Bioactivity and Antimicrobial Activity of Picea abies and Larix decidua Wood and Bark Extracts

Abstract: Picea abies and Larix decidua were subjected to GC/MS analyses, and antimicrobial (fungi and bacteria) assays of their stem wood and bark extracts were investigated. L. decidua bark extract exhibited the highest antifungal and antibacterial activities against the microorganisms that were screened. The microbes Penecillium ochrochloron and Aspergillus ochraceus were the most sensitive to the extracts, whereas Candida albicans was the most resistant fungus. L. decidua wood and bark did not exhibit much variation in their antibacterial activities, except against Micrococcus flavus and Pseudomonas aeruginosa. The bacterium most sensitive to the extracts was Escherichia coli, whereas the most resistant was M. flavus. 13-epimanool and α-cedrol were the main components of P. abies wood extract. The main components in its bark were abietic acid, astringin, dehydroabietic acid, and α-terpineol. The main chemical compounds in L. decidua wood extract were abietic acid, oleanolic acid, duvatrienediol, and larixol. The main chemical compounds in its bark were (-)-2,9-dihydroxyverrucosane and larixol. The study revealed that P. abies and L. decidua stem wood and bark extracts contain several compounds that have antimicrobial activities towards diverse human pathogenic, food, and agricultural microbes. These results might guide in future searches for novel natural products with chemotherapeutic uses.

Comparative study of the essential oils of three Beilschmiedia species and their biological activities

Abstract: Summary This study was designed to examine the chemical compositions of the essential oils from three Beilschmiedia species and antioxidant, antimicrobial, antityrosinase, acetylcholinesterase and anti-inflammatory activities. The essential oils of B. kunstleri, B. maingayi, B. penangiana gave β-caryophyllene (10.6–12.1%), β-eudesmol (17.5–24.1%) and δ-cadinene (17.5–28.7%) as the most abundant components respectively. The bark oil of B. maingayi showed the highest activity in β-carotene/linoleic acid (125.9%) and phenolic content (288.2 mg GA g−1), while B. penangiana bark oil was found to have strong activity in DPPH (IC50 84.7 μg mL−1) and ABTS (IC50 108.3 μg mL−1). The essential oils of B. penangiana showed the best activity against Candida glabrata with MIC value 31.3 μg mL−1. The bark oil of B. penangiana gave 82.5% tyrosinase inhibiton. The leaf oil of B. maingayi gave the highest inhibition in AChE (66.6%) and lipoxygenase (77.0%) assay. Our findings demonstrate that the essential oils have great potential for applications in pharmaceutical and food industries.

STRUCTURE AND THERMAL BEHAVIOR OF TANNINS FROM Acacia dealbata BARK AND THEIR REACTIVITY TOWARD FORMALDEHYDE

Abstract: The objective of this study was to evaluate the tannin extraction potential taken from the bark of Acacia dealbata. This tannins were extracted with water at 90°C. An extraction yield of 17.2% solids with a Stiasny number of 82% was obtained from the bark extract of Acacia dealbata. The structure was studied by Fourier transform infrared spectroscopy (FTIR). The thermal behavior of tannins was studied by DSC and a glass- transition temperature (Tg) of 116,77°C was determined. The thermal stability of tannins was studied by TGA. At 196.91°C the decomposition is 3.7% and the maximum of the weight loss rate (DTG) of the degradation was 257.77°C. The curing with formaldehyde showed an exotherm reaction in the range of 100-120°C, which is similar to tannins of other species.

Hot water extraction of Norway spruce (Picea abies [Karst.]) bark: analyses of the influence of bark aging and process parameters on the extract composition

Abstract: The hot water (HW) extraction of Norway spruce (Picea abies [Karst.]) delivers condensed tannins and considerable amounts of other compounds. Yield and composition of the HW extracts were investigated as a function of natural weathering for up to 15 months. Total phenol monomers and oligomers were detected by Folin-Ciocaltau assay after fractionation by solid phase extraction (SPE). Procyanidins (PC) were determined by HPLC-UV after acid thiolysis and carbohydrates by HPLC combined with acid hydrolysis. Topochemistry of the bark before and after extraction was investigated by UV-microspectrometry (UMSP) and non-extractable PC analyzed by direct thiolysis on the bark. The influence of the parameters on the yield and composition of the extracts were evaluated, such as the extraction temperature, time and the addition of sodium sulfate and urea. Prolonged weathering resulted in a considerable decrease of the total extraction yield, partly because of leaching of phenolic monomers, mono- and oligosaccharides. The yield of phenolic oligomers also decreased at a moderate rate, while the yield of polysaccharides (pectins) was almost stable. Nonextractable and non-leachable compounds deposited in the cell lumens represent the majority of the phenolic extractives in spruce bark. Sequential extractions performed at increasing temperature proved to be a suitable method for the recovery of tannin-rich extracts.

In Vitro Dermo-Cosmetic Evaluation of Bark Extracts from Common Temperate Trees

Abstract: Wood residues produced from forestry activities represent an interesting source of biologically active, high value-added secondary metabolites. In this study, 30 extracts from 10 barks of deciduous and coniferous tree species were investigated for their potential dermo-cosmetic use. The extracts were obtained from Fagus sylvatica, Quercus robur, Alnus glutinosa, Prunus avium, Acer pseudoplatanus, Fraxinus excelsior, Populus robusta, Larix decidua, Picea abies, and Populus tremula after three successive solid/liquid extractions of the barks with n-heptane, methanol, and methanol/water. All extracts were evaluated for their radical scavenging capacity, for their elastase, collagenase, and tyrosinase inhibitory activities, as well as for their antibacterial activity against gram-positive Staphylococcus aureus. In parallel, the global metabolite profiles of all extracts were established by 1D and 2D NMR and related to their biological activity. The results showed that the methanol extracts of Q. robur, A. glutinosa, L. decidua, and P. abies barks exhibit particularly high activities on most bioassays, suggesting their promising use as active ingredients in the dermo-cosmetic industry.

Morphology and Overall Chemical Characterization of Willow (Salix sp.) Inner Bark and Wood: Toward Controlled Deconstruction of Willow Biomass

Abstract: The morphology and chemical composition of the inner bark of four willow hybrids were analyzed as a step toward complete willow biomass valorization. The inner bark consisted of highly delignified bundles of thick-walled sclerenchyma fibers and nondelignified surrounding tissue of thin-walled parenchyma cells. In comparison with willow wood fibers, the sclerenchyma fibers were longer, they had a very narrow lumen and their walls were made of up to eight separate layers. One fourth of the dry mass of the inner bark was formed of ash and acetone extractable substances. Although the lignin-to-polysaccharide ratio was similar in the inner bark and wood, their polysaccharide compositions were different. While glucose and xylose were the main monomers in wood, the inner bark had also high arabinose and galactose contents. In addition, more rhamnose was present in the inner bark which was indicative of its higher pectin content.

Faunal community consequence of interspecific bark trait dissimilarity in early-stage decomposing logs

Abstract: Dead tree trunks have significant ecosystem functions related to biodiversity and biogeochemical cycles. When lying on the soil surface, they are colonized by an array of invertebrate fauna, but what determines their community composition is still unclear. We apply community assembly theory to colonization of tree logs by invertebrates. During early decomposition, the attached bark is critically important as an environment filter for community assembly through habitat provision. Specifically, we hypothesized that the more dissimilar bark traits were between tree species, the more their faunal community compositions would differ. We tested this hypothesis by investigating the effects of bark traits on the invertebrate communities in the early-decomposing logs of 11 common, temperate tree species placed in the ‘common garden’ experiment LOGLIFE. Bark traits included bark looseness, fissure index, outer bark thickness, ratio of inner to outer bark thickness, punch resistance, water storage capacity and bark pH. The predominant faunal groups studied were Annelida, Isopoda, Chilopoda, Diplopoda, Diptera and Coleoptera. Our results showed (i) strong interspecific differences in bark traits, (ii) that bark traits related to environmental buffering had profound effects on the abundance of specific invertebrate groups, and (iii) the higher the overall bark trait dissimilarity between tree species, the more dissimilar these tree species were in faunal community composition, and the higher was the joint invertebrate family richness. A suite of bark traits together has fundamental afterlife effects on invertebrate community assembly, strongly filtering the colonizing invertebrates in early-decomposing logs, driving variation in their community composition and diversity. Our findings indicate that bark trait dissimilarity among tree species in forest stands is likely a better indicator of early-phase dead trunk fauna diversity than tree species diversity per se. A lay summary is available for this article.

Factors controlling bark decomposition and its role in wood decomposition in five tropical tree species.

Abstract: Organic matter decomposition represents a vital ecosystem process by which nutrients are made available for plant uptake and is a major flux in the global carbon cycle. Previous studies have investigated decomposition of different plant parts, but few considered bark decomposition or its role in decomposition of wood. However, bark can comprise a large fraction of tree biomass. We used a common litter-bed approach to investigate factors affecting bark decomposition and its role in wood decomposition for five tree species in a secondary seasonal tropical rain forest in SW China. For bark, we implemented a litter bag experiment over 12 mo, using different mesh sizes to investigate effects of litter meso- and macro-fauna. For wood, we compared the decomposition of branches with and without bark over 24 mo. Bark in coarse mesh bags decomposed 1.11–1.76 times faster than bark in fine mesh bags. For wood decomposition, responses to bark removal were species dependent. Three species with slow wood decomposition rates showed significant negative effects of bark-removal, but there was no significant effect in the other two species. Future research should also separately examine bark and wood decomposition and consider bark-removal experiments to better understand roles of bark in wood decomposition.

Antioxidant and Hepatoprotective Potentiality of Randia dumetorum Lam. Leaf and Bark via Inhibition of Oxidative Stress and Inflammatory Cytokines

Abstract: Randia dumetorum Lam. (RD) (Rubiaceae) is traditionally used by some tribes of Assam and Manipur of North East India for the treatment of liver ailments. In this context, to scientifically validate this indigenous traditional knowledge, we have evaluated the antioxidant and hepatoprotective activity of RD leaf and bark. The methanol extracts of RD leaf and bark were evaluated for in vitro antioxidant activity which exhibited good anti-oxidant activity in terms of reducing power assay, total antioxidant assay and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging assay. Total phenolic and flavonoid content were found to be 112 ± 3.24 mg and 138 ± 2.46 mg gallic acid equivalents/g extract and 2.6 ± 0.26 mg and 3.34 ± 0.31 mg rutin equivalents/g extract respectively for RD leaf and bark methanol extracts. The In vivo hepato protective activity of the RD leaf and bark extract was evaluated against carbon tetrachloride (CCl4) induced hepatic damage in male wistar rats. CCl4 administration induced hepatic damage in rats resulted in increased levels of aspartate transaminase, alanine transaminase, alkaline phosphatase, lactate dehydrogenase, thiobarbituric acid reacting substances, albumin, bilirubin, TNF-α, IL-1β and decreased levels of total protein and antioxidant enzymes like superoxide dismutase, catalase and glutathione reductase. RD leaf and bark methanol extracts pre-treatment exhibited protection against CCl4 induced hepatotoxicity by reversing all the abnormal parameters to significant levels. Histopathological results revealed that RD leaf and bark extracts at 400 mg/kg protects the liver from damage induced by CCl4. The results of this study scientifically validate the traditional use of RD leaf and bark for the treatment of liver ailments.

The (w)hole story: Facilitation of dead wood fauna by bark beetles?

Abstract: Facilitation between species is thought to be a key mechanism in community assembly and diversity, as certain species create microhabitats for others. A profound characteristic of forest ecosystems is a large amount of dead wood which is colonised by a vast array of invertebrate species. Bark beetles (Scolytinae) feed and breed on dying or dead trees, puncturing holes into the bark and engraving inner bark and outer wood with their galleries. These holes and galleries might facilitate other invertebrates by providing access to the inner bark for shelter, feeding and reproduction. We tested this hypothesised facilitative interaction during the early decomposition phase of coarse woody debris of spruce (Picea abies L. Karst.) incubated in two environmentally contrasting forest sites in the 'common garden' experiment LOGLIFE. We sampled invertebrates in 25 cm diameter logs at different degrees of colonisation by bark beetles. Our results indicated that (1) bark beetles facilitated the entrance into spruce logs of other invertebrates with body width that matched the size of bark-beetle holes, and (2) the abundance of invertebrates was often positively related to the proportional surface area of inner bark consumed by bark beetles, but more so in the nutrient-rich site than in the nutrient poor site. This study provides the first quantitative test of facilitation between invertebrate clades in dead wood communities. Including facilitative interaction in community assembly studies may change some predictions about relationships between tree functional traits and invertebrate diversity and will lead to a more accurate and comprehensive understanding of dead wood communities.

Chemical characterization of cork and phloem from Douglas fir outer bark

Abstract: Cork and phloem from Pseudotsuga menziesii outer bark were separated, fractionated and the 40- to 60-mesh fractions chemically analyzed. Cork and phloem showed a different grinding behavior with the highest yields for cork and phloem, respectively, for the 40- to 60-mesh fraction (31.4%) and the < 0.180-mm fraction (49.2%). Cork chemical composition was (% o.d. mass): ash 0.9%; extractives 29.2% (mostly polar, 23.5%); lignin 16.8%, and suberin 36.2%. Polysaccharides (16.9%) con- tained glucose (55.4% of total neutral carbohydrates), xylose (13.3%), mannose, arabinose, and galactose as minor components. Lipophilic and suberin extracts from cork and phloem were analyzed by GC-MS, directly and after alkaline hydrolysis. In cork, catechin was the major compound identified in the lipophilic extract, accom- panied by ferulic acid and acylglycerols. In phloem, β-sitosterol was the major compound. The content of fatty alcohols and fatty acids increased after hydrolysis confirming their esterification in both extracts. Suberin from P. menziesii cork is rich in saturated ω-hydroxyacids (ω-hydroxyacids 36.2%, α,ω-diacids 18.6%, alkanoic acids 6.2%, and alkanols 8.7%), being different from suberin of Quercus suber where α,ω-diacids are dominant.

Factors controlling bark decomposition and its role in wood decomposition

Abstract: Organic matter decomposition represents a vital ecosystem process by which nutrients are made available for plant uptake and is a major flux in the global carbon cycle. Previous studies have investigated decomposition of different plant parts, but few considered bark decomposition or its role in decomposition of wood. However, bark can comprise a large fraction of tree biomass. We used a common litter-bed approach to investigate factors affecting bark decomposition and its role in wood decomposition for five tree species in a secondary seasonal tropical rain forest in SW China. For bark, we implemented a litter bag experiment over 12 mo, using different mesh sizes to investigate effects of litter meso- and macro-fauna. For wood, we compared the decomposition of branches with and without bark over 24 mo. Bark in coarse mesh bags decomposed 1.11–1.76 times faster than bark in fine mesh bags. For wood decomposition, responses to bark removal were species dependent. Three species with slow wood decomposition rates showed significant negative effects of bark-removal, but there was no significant effect in the other two species. Future research should also separately examine bark and wood decomposition, and consider bark-removal experiments to better understand roles of bark in wood decomposition.

Comparison of in vitro antioxidant activity of infusion, extract and fractions of Indonesian cinnamon (Cinnamomum burmannii) bark.

Abstract: The purpose of this research was to compare antioxidant activity of Indonesian cinnamon bark infusion, extract, its fractions and to analyse of their phytochemical constituents for antioxidant activity. The cinnamon infusion was obtained by water extraction, while the extract was by ethanol percolation. The ethanolic extract was then fractionated into n-hexane, ethyl acetate and water fractions.Their in vitro antioxidant activity was assayed semiquantitatively by using DPPH method, while the phytochemical constituents were analyzed by using TLC-autography with several spray reagents.The results showed that antioxidant activity of infusion, extract and its fractions were significantly different. Among the material tested, the cinnamon bark infusion had the highest antioxidant activity, followed by ethanolic extract, its waterand ethyl acetatefractions with IC50 value of 3.03; 8.36; 8.89; and 13.51μg/mL, respectively. Their antioxidant activities were higher than rutin, with IC50 of 15.27 μg/mL.The phytochemical analysis results indicated that polyphenol (tannin, flavonoids) and phenolic volatile oil are the major antioxidant compounds.