Outer Bark Research Articles

Plant diseases associated with olive bark midge in West-Bank Palestine

Olive tree is one of the most cultivated trees over the Palestinian territories, it is considered as the mainstay of rainfed agriculture in Palestine. Recently and due to the impact of the global warming, olive trees were infected with an outbreak of many pests and pathogens. In the last decades, both olive fruit fly, Bactrocera oleae (Diptera, Tephritidae) and peacock leaf spot, Spilocaea oleagina were reported with an unusual percentage of infections over the olive trees. During 2015–16, and throughout the field surveys to investigate any unusual diseased symptoms on olives; some trees exhibited pale yellowing on the newly formed branches, symptoms associated with viral infections such as OLYaV. Some other trees were noticed to get yellowing and later on developed branch dieback and stem canker and cracking syndromes. When the outer bark was removed, the affected tissue appeared dark brown, in contrast to the yellowish green of healthy inner bark. These symptoms were observed on both young and old trees in the northern part of Palestine. Field and laboratory investigation revealed a heavy infestation with larvae of Resseliella oleisuga Targ. (Diptera: Cecidomyiidae). The infestation rate reported ranged from 75 to 92 in some olive orchards. Pathogens were isolated and identified based on cultural morphology. Climate changes due to the global warming might be the cause of this outbreak; probably due to the changes in the environmental conditions favoured by the insects. To our knowledge, this is the first time this insect was reported to be widely spread of olive trees and causing damage in Palestine. In this study, several associated primary, secondary and saprophytic diseases were detected from the infected samples. Mainly Botryosphaeria spp., Alternaria solani Sor., Aspergillus niger v. Tieghem, Cladosporium herbarum Fr., Fusarium solani (Mart.) App., Penicillium digitatum Sacc., Penicillium italicum Wehmer, Rhizopus stolonifer (Her.) Vuill.

Savanna trees do not have thicker outer bark than forest trees of two tropical species

Although the outer bark is important for protecting the inner tissues of stems of woody plants, especially from fire, the variation of outer bark in environments with different water availability, wind intensities, and solar radiation is little understood. Here, we examined the outer bark structure of Moquiniastrum polymorphum (Asteraceae) and Zanthoxylum rhoifolium (Rutaceae), co-occurring species in cerrado sensu stricto, cerradão, semi-deciduous seasonal forest and rainforest. Cerrado sensu stricto is a savanna with relatively intense solar radiation and winds. Cerradão, semi-deciduous seasonal forest and rainforest are progressively more closed and humid. We tested if trees in cerrado sensu stricto have relatively thicker outer and total bark than trees in the other three environments. For individuals of each species from each habitat, we described the morphological and anatomical features of the outer bark, including the origin of the first periderm. We compared the relative thickness of outer and total bark among habitats by means of ANOVA. In both species, we observed no qualitative differences in the morphological and anatomical features of the outer bark; therefore, these features are diagnostic for each species. For all habitats, the deep-seated origin of the first periderm and formation of a rhytidome in M. polymorphum produce a grooved bark with a loose appearance, whereas the subepidermal origin and formation of a single periderm in Z. rhoifolium produce a more uniform and smooth-appearing bark. Zanthoxylum rhoifolium trees in cerrado sensu stricto and cerradão have a thinner periderm, whereas M. polymorphum trees do not vary in rhytidome thickness among the habitats. In summary, trees from cerrado sensu stricto did not have relatively thicker outer bark and total bark than trees in cerradão, semi-deciduous seasonal forest and rainforest, suggesting that seasonal drought, intense solar radiation and winds do not seem to affect the total thickness of the outer bark.

Results of a controlled field experiment to assess the use of tree tissue concentrations as bioindicators of air Hg

The utility of trees as bioindicators of atmospheric mercury (Hg) depends upon how accurately tree tissue concentrations reflect air-Hg concentrations at a given location and time. The relationship between air-Hg, and Hg concentration in tree tissues was investigated using potted Pinus nigra (Austrian pine) saplings 6 to 7 years in age moved from a tree farm in Oregon, USA, to three locations with different weather, two with different air total Hg (THg) concentrations, all with different predominant gaseous oxidized Hg chemistry, and one being impacted by the marine boundary layer. An aqueous Hg bromide root spike showed no significant effect on above ground tissue concentration. Over two growing seasons, needles, bark, and tree rings were sampled and analyzed for THg concentrations to compare with those collected when the trees originally arrived in Reno, NV (control) versus that measured in the new locations. Overall, foliar Hg concentrations increased significantly at all new locations relative to the control. Spring sample concentrations were lower than fall for foliage at two locations, indicating resorption of Hg along with nutrients. All trees had higher mean Hg concentrations in the outermost tree rings relative to the control, consistent with increased air total Hg concentrations and changing air chemistry. Higher concentrations were measured in the outer bark of trees where ambient GOM concentrations were highest. Higher inner bark concentrations were correlated with the more humid location where high methylmercury concentrations have been measured in fog. Results demonstrated that Pinus nigra tissues are effective biomonitors for air Hg exposures and that translocation from leaves to rings via the phloem is an important pathway for sequestration in plant tissue. We also show that plants are active assimilators of atmospheric Hg, and as such, local environmental conditions influence ring, bark, and foliage concentrations. The latter has important implications for understanding tissue Hg concentrations, and supports the use of tree ring Hg concentrations as archives.

Archaeo-inspired material synthesis: sustainable tackifiers and adhesives from birch bark

Pitch obtained through pyrolysis of the outer bark of birch trees (Betula pendula) belongs to the oldest thermoplastic glues fabricated by mankind. Inspired by archaeological findings, several products with beneficial properties for modern adhesive applications were generated through torrefaction of white birch bark from 260 to 340°C. The process was inspired by the ancient two-pot method. Solvent extraction with acetone was applied to isolate the specific adhesive compounds from the torrefaction residue. The chemical structure of the products was completely identified for the first time. The obtained betulin esters of suberin and suberinic fatty acids represent a new class of tackifying agents suitable for adhesive applications. The products exhibit excellent adhesive properties, and the glass transition temperature T g could be adjusted between −11 and 52°C by controlling the pyrolysis temperature and duration. Products with a T g higher than 30°C are well suited as tackifying agents for adhesives, while pitches with a lower T g can be used as low-viscosity hot melts. The fabricated archaeo-inspired adhesives can be obtained in very high yields (15–27% (m/m)) and are virtually odourless.

First Report of Diplodia corticola Causing Stem and Branch Cankers on White Oak (Quercus alba) in Missouri, U.S.A.

An investigation of white oaks (Quercus alba) with thin crowns, branch dieback, or both was performed in Crawford and Washington counties, Missouri, during September 2015. Affected stem and branch segments were cut from each tree for examination. After debarking, isolations were performed by using a sterile scalpel to cut cubes (approximately 2 mm³) from tissues at the edges of cankers and underlying stained sapwood. Cubes were placed in quarter-strength potato dextrose agar (PDA) amended with chloramphenicol and streptomycin sulfate (100 mg/liter). A fungus frequently recovered from four of six symptomatic trees was suspected to be a Botryosphaeriaceae species based on its colony morphology, reproductive structures, and conidia (Alves et al. 2004). DNA was extracted from seven isolates, and the internal transcribed spacer (ITS) and the gene portions of nuclear ribosomal small subunit (SSU) regions were sequenced after amplification using ITS1F and ITS4 and NS1 and NS4 primers (White et al. 1990). The resulting sequences were deposited in GenBank (accession nos. MH041506 to MH041510, MH036328, and MH036329). Contigs had 100% homology with the ITS and SSU regions of multiple Diplodia corticola isolates (accession nos. KX595187.1, KT440896.1, KX463057.1, KF766239.1, and EU673206.1). Two isolates were chosen as inocula for a pathogenicity test. In a greenhouse trial, five 2-year-old seedlings were inoculated with isolate 25, and another five seedlings were inoculated with isolate 101. The fully leafed and healthy, potted seedlings were exposed to natural light. Inoculations were made by puncturing the bark of seedling stems 5 cm above the soil surface with a sterile 8-mm-diameter cork borer, peeling back the outer bark, and placing PDA bearing mycelium of either isolate into the wound. The bark was replaced and the wound wrapped with Parafilm. As a control treatment, a sterile plug of noncolonized PDA was wound inoculated 10 cm above the D. corticola inoculation site. The bark was peeled from the wounds at 8 weeks. Canker shapes were drawn on transparency film and photographed prior to measuring length and surface area with ImageJ 1.51j8 (from the National Institutes of Health). Stems were split in half and cankers measured lengthwise. Tissues were removed from the canker margin and placed in PDA for recovery of the pathogen. Vascular tissues were sampled at 0, 1, 2, and 3 cm above and below the control wound to determine if D. corticola had spread from the inoculation to the control wound. Cankers of variable sizes developed around wounds. Mean (and range) of canker areas were 4.5 cm² ± 1.4 cm² SE (2.3 to 9.1 cm²) for isolate 25 and 4.9 cm² ± 1.7 cm² SE (1.1 to 9.6 cm²) for isolate 101. The means for lengths of cankers induced by isolates 25 and 101 were 5.7 ± 0.6 and 4.6 ± 1.0 cm, respectively, when measured on stems split lengthwise. Xylem was discolored to the pith for four of five and two of five wounds inoculated with isolates 25 and 101, respectively. Cankers did not develop on wounded controls. D. corticola was recovered from canker edges from three of five seedlings for each isolate but not from sampled tissues 0, 1, 2, or 3 cm from control wounds. Hence, the pathogen did not progress far from the inoculation point. The identities of the recovered isolates were confirmed by sequencing the ITS region. This is the first report of D. corticola-caused cankers on oaks in Missouri. Earlier reports have shown that D. corticola causes cankers on Q. alba and other oak species also abundant in Missouri’s oak-dominated forests (Acimovic et al. 2016; Munck et al. 2017; Smith and Stanosz 2018). The role of D. corticola in oak dieback and mortality bears further study to understand any potential impacts on oaks that are of predominant importance in Missouri forests.

Correlation between macroscopic characteristics and tissue-specific chemical profiling of the root of Salvia miltiorrhiza

BackgroundMacroscopic identification has been widely used as a convenient method for herbal authentication and quality assessment. However, sensory evaluation heavily relied on personal experience and lacked enough evidence-based validations. PurposeWe aim to reveal the correlation between macroscopic characteristics and tissue-specific chemical composition of the root of Salvia miltiorrhiza (SMR), and then develop a rapid method for quality assessment. MethodsThirty-two batches of SMR were collected and evaluated. The outer-surface color and diameter as the representative tissue features of SMR were selected as the macroscopic indexes. SMR were then divided into three parts along transverse section as outer bark, middle part and central part, to explore the spatial distribution of chemicals. Outer-surface color information was converted into RGB values, while the diameter data were expressed by mean distance, respectively. Thirteen major components including eight salvianolic acids and five tanshinones in each part were determined by liquid chromatography tandem mass spectrometry. Finally, several mathematical models were established and optimized to evaluate the correlation between outer-surface color, size and chemical distribution. ResultAll five tanshinones mainly distributed in the outer bark while salvianolic acids were averagely existed among three parts. Correlational studies revealed that the surface color depth was significantly and positively correlated with tanshinone contents in the outer bark, while the size showed poor correlation in any chemicals. A color-oriented model was thus developed for the prediction of tanshinone contents in SMR, and a 9 × 9 standard color chart was created for easily use. ConclusionThis study contributes an alternative method for macroscopic features-based quality evaluation of herbs, and also complements some scientific data for traditional knowledge.

The effects of strimmer damage to young ash trees (Fraxinus excelsior L.)

ABSTRACTStrimming near the bases of young trees can often cause wounds that remove outer bark and cause damage, dysfunction and death to the living tissues of the tree, making trees vulnerable to pathogen ingress.This study conducted quantitative research into the effect of mechanical wounding by causing strimmer damage to 88 fifteen-year-old ash trees (Fraxinus excelsior L.) in a woodland setting. Damaged specimens were sequentially harvested and wound parameters measured over a 2-year period and compared to a control. Inner bark death, sapwood discolouration and the formation of woundwood caused by this wounding was analysed.In addition, two industry questionnaires were issued to gather the opinions of those in a supervisory/management position and those directly involved with grounds maintenance operations that involved strimming near to trees.Results from the strimmer-damaged ash trees identified that the initial wound size increased by, on average, 46.5% over the first 8 months after injury, due to the necrosis of inner bark adjacent to the wounds. The extent of the sapwood exposed was correlated with the length of time taken for the wounds to occlude, most of them occluding within one growing season. The associated questionnaires identified that strimmer damage to urban trees is seen daily by some operatives and that managers favour operator training over other solutions to this problem.We conclude that advanced technical training of operatives is essential as a preventive measure against strimmer damage to trees but that other methods of tree protection should also be considered.

Six-year monitoring study of radiocesium transfer in forest environments following the Fukushima nuclear power plant accident

The study investigated temporal changes in the 137Cs concentrations in vegetal and hydrological samples collected from various forests in Yamakiya District, Kawamata Town of Fukushima prefecture over six years following the Fukushima Dai-ichi nuclear power plant accident. Cesium-137 was detected in all forest environmental samples. However, the concentration in most samples decreased exponentially with time. The 137Cs concentrations in throughfall samples exhibited a double-exponential decreasing trend with time. Temporal changes in the 137Cs concentration in vegetal samples and stemflow were approximated by using a single-exponential equation. A comparison of the decline coefficient for the latter observation period (>2 y since the accident) revealed that the declining trend of 137Cs concentrations varied between foliage and the outer barks of the Japanese cedar and Japanese konara oak trees. The 137Cs concentration in cedar needles decreased exponentially while that in konara oak leaves was constant over the last six years. Conversely, the declining trend of 137Cs concentration in the outer bark of konara oak exceeded that of cedar. The results suggested that self-decontamination processes and internal recycling of 137Cs varied among tree species and different tree parts. The results indicated that the leaching of 137Cs in the throughfall in Japanese cedar was dependent on the 137Cs concentration in needles. However, a comparison of 137Cs concentrations in vegetal and hydrological samples from each sampling year showed that the leaching rate decreased with time. Conversely, the 137Cs concentrations in the stemflow were independent of the concentrations in the outer bark. The declining trend of 137Cs concentrations in litterfall (λ: 0.31–0.33 y−1) was similar to that of the mean of new/old needles (λ: 0.26–0.33 y−1) for cedar stands. With respect to the hydrological components, the 137Cs concentration in the stemflow (λ: 0.32–0.33 y−1) decreased at a slightly slower rate than that in the throughfall (λ: 0.36–0.54 y−1) for the cedar forest. The decline coefficients of 137Cs concentration in the aforementioned types of hydrological components slightly exceeded that for the vegetal samples. The results suggest that monitoring of 137Cs concentrations in hydrological components and vegetal samples can aid in further understanding the leaching mechanisms of 137Cs from trees to rainwater.

Chemical composition and cellular structure of ponytail palm (Beaucarnea recurvata) cork

Ponytail palm (Beaucarnea recurvata Lemaire) is a succulent plant indigenous to Mexico frequently used as an ornamental plant throughout the world. The mature trees develop a thick corky outer bark that was studied here for the first time and compared with cork of Quercus suber Linnaeus (cork oak) and other species. The anatomical structure of ponytail palm cork showed a typical honeycomb structure in the tangential section and a brick-wall layer in the transverse section. The cells were larger and had thicker cell walls than those of Q. suber cork. Ponytail palm cork had a distinct growth ring pattern but the cell wall undulation lacked the regular wave pattern as in Q. suber cork. Fiber-like cellular structures were present protuberating from the lenticular channels. Ponytail palm cork chemically differs from Q. suber and other corks by a much lower content of suberin and enhancement of the lignocellulosic nature (18.2% extractives, 11.8% suberin, 29.7% lignin and 39.0% polysaccharides). Although in general similar to that of Q. suber cork, suberin composition of ponytail palm cork has specific features namely regarding the ratio of ɑ,ω-diacids and ω-substituted hydroxyacids and presence of higher amounts of alkanoic acids. The lignin of ponytail palm cork is a HGS-type of lignin (1:12:5) with a S/G ratio of 0.4. These results add to data showing that monomeric composition of suberin and lignin of corks are species’ specific. The lipophilic extractives included mainly saturated alkanoic acids and sterols while the polar extractives showed overall low amount of phenolics and unremarkable antioxidant properties.

Recognizing Amazonian tree species in the field using bark tissues spectra

The identification of tree species in the field is often a subjective process and misidentifications cause many problems for forest management in the Amazon Forest. Near infrared spectra from dried leaves of herbarium specimens are able to distinguish species in tropical forests. However, toolsto improve species identification directly in the field are needed. In this study, we tested whether spectral reflectance of bark tissues (rhytidome and phloem) collected with a portable spectrometer in the field can be used for the discrimination of tree species. Spectral data was collected for 254 trees of 8 families, 10 genera and 11 species from terra firme forests in Central Amazon with an ASD field spectrometer. Data consisted of reflectance values within 350–2500 nm wavelengths. We compared the rate of correct species recognition for different datasets using linear discriminant models. The rate of correct species assignment using this technique was 98% when using spectra from the inner bark (phloem) and 94% with outer bark (rhytidome) spectra. We suggest that the application of this technique can improve the quality of species identification directly during field inventories, fostering better forest management practices.

Betulinic Acid Exerts Cytotoxic Activity Against Multidrug-Resistant Tumor Cells via Targeting Autocrine Motility Factor Receptor (AMFR).

Betulinic acid (BetA) is a naturally occurring pentacyclic triterpene isolated from the outer bark of white-barked birch trees and many other medicinal plants. Here, we studied betulinic acid's cytotoxic activity against drug-resistant tumor cell lines. P-glycoprotein (MDR1/ABCB1) and BCRP (ABCG2) are known ATP-binding cassette (ABC) drug transporters that mediating MDR. ABCB5 is a close relative to ABCB1, which also mediates MDR. Constitutive activation of the EGF receptor is tightly linked to the development of chemotherapeutic resistance. BetA inhibited P-gp, BCRP, ABCB5 and mutation activated EGFR overexpressing cells with similar efficacy as their drug-sensitive parental counterparts. Furthermore, the mRNA expressions of ABCB1, BCRP, ABCB5 and EGFR were not related to the 50% inhibition concentrations (IC50) for BetA in a panel of 60 cell lines of the National Cancer Institute (NCI), USA. In addition to well-established MDR mechanisms, we attempted to identify other molecular mechanisms that play a role in mediating BetA's cytotoxic activity. For this reason, we performed COMPARE and hierarchical cluster analyses of the transcriptome-wide microarray-based mRNA expression of the NCI cell lines panel. Various genes significantly correlating to BetA's activity were involved in different biological processes, e.g., cell cycle regulation, microtubule formation, signal transduction, transcriptional regulation, chromatin remodeling, cell adhesion, tumor suppression, ubiquitination and proteasome degradation. Immunoblotting and in silico analyses revealed that the inhibition of AMFR activity might be one of the mechanisms for BetA to overcome MDR phenotypes. In conclusion, BetA may have therapeutic potential for the treatment of refractory tumors.

Selecting a Green Strategy on Extraction of Birch Bark and Isolation of Pure Betulin Using Monoterpenes

The aim of this work is to study sustainable approaches to pure betulin using green low-polar solvents from natural feedstock—pine monoterpenes and limonene. The conventional methods of extracting outer birch bark (OBB) lead to extracts that contain only 50%–75% of betulin, while refining processes of OBB extracts are usually labor consuming and employ toxic solvents. The extractions of OBB using monoterpenes and their hydrogenated analogs at boiling and microwave-assisted conditions turned out to be insufficiently selective and lead to a significant uptake of extractants on the depleted bark. To obtain pure betulin, the sequence including energy-saving extraction of OBB with a green solvent (ethyl acetate, EtOAc), saponification of the extract, and purification of betulin in limonene or hydrogenated monoterpenes was proposed. The protocol of processing primary extracts with stable monoterpenes—limonene, pinane, and hydrogenated turpentine oil—ensured separation of pure betulin (95%–97%) with high yields ...

Inhibitory activities of tree bark extracts against AGEs formation and their correlation with phenolic components

Advanced glycation end-products (AGEs) are one of the pivotal factors that cause a variety of diabetes complications. To explore a new class of natural resources that can prevent AGEs formation, the inhibitory activities of tree bark extracts against AGEs formation were evaluated. Most of the crude extracts of inner or outer bark showed equal or superior inhibitory activities to aminoguanidine, a conventional AGEs formation inhibitor. The quantification of phenolic components of each bark extract revealed that proanthocyanidins were one of the principal factors for inhibition, whereas flavonoids, such as flavones/flavonols and flavanones/dihydroflavonols were not a major factor. This study focused on the outer bark extract from Betula platyphylla which showed exceptionally high activity despite its low contents of total phenolics and proanthocyanidins. The bioassay-guided isolation revealed that betulin caffeate and its two derivatives were active principles in extract of B. platyphylla. These compounds exhibited up to ninefold higher activity than methyl caffeate, which suggested that betulin moiety plays a synergistic role in the activity. These results demonstrated the potency of bark extract as the screening source of AGEs inhibitors and also provided a new insight for the exploration of anti-AGEs substances from natural resources.

Water repellency improvement of cellulosic textile fibers by betulin and a betulin-based copolymer

Betulin is a naturally abundant and hydrophobic compound in the outer bark of birch and can readily be obtained by solvent extraction. Here, solutions of betulin were used to treat cotton fabrics and improve their water repellency. Cotton fabric impregnated in a solution of betulin in ethanol showed a contact angle for water of approximately 153° and reached a water repellency score of 70 according to a standard water repellency test method. A betulin-terephthaloyl chloride (TPC) copolymer was synthesized. Both betulin and betulin-TPC copolymer were characterized by nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. The copolymer was characterized by size exclusion chromatography and differential scanning calorimetry. When impregnated with a solution of betulin-TPC copolymer in tetrahydrofuran, a cotton fabric showed a water contact angle of 151° and also reached a water repellency score of 70. Films based on betulin and betulin-TPC copolymer were prepared and coated onto the surface of the fabrics by compression molding. These coated fabrics showed water contact angles of 123° and 104° respectively and each reached a water repellency score of 80.

Tree-level distribution of a novel insect-pathogen complex and its potential contribution to eastern white pine dieback

Bottom-up branch dieback and sapling mortality of eastern white pine (Pinus strobus L.) has been observed range-wide during the last two decades. Observational studies thus far implicate these symptoms to an insect, the eastern white pine bast scale (Matsucoccus macrocicatrices Richards), and a canker-forming, fungal pathogen, Caliciopsis pinea Peck. The scale insect was historically considered an innocuous herbivore of eastern white pine restricted only to New England and Canada, but is now found in high densities on symptomatic trees, in close association with Caliciopsis canker, and in almost every region where the host grows. We sampled branches and boles of eastern white pines in the southern Appalachians to better understand the distribution of the insect-pathogen complex on individual trees and among size classes. Results indicate distinct patterns, as branches of poletimber, boles of saplings, and branches lowest in the canopy harbored the greatest numbers of bast scales and had the highest proportional Caliciopsis canker area. The incidence of scales and cankers was generally highest on older tissue with high percent lichen cover, but with thinner outer bark. Tree-level distribution of the bast scale and Caliciopsis canker was non-random and in fact mirrored the observed dieback patterns reported for eastern white pine, indicating that these two organisms may be important contributors to tree dieback and mortality in the southeastern USA.

Stability Studies of Bioactive Compounds from Birch Outer Bark Ethanolic Extracts

The literature survey summarizes information about birch outer bark phytochemical composition and details major components: betulin, betulinic acid, lupeol and ursolic acid. In the practical part of research birch outer bark major component stability against chemical and physical degradation was tested; total phenolic content and the antiradical activity of the degraded and nondegraded ethanolic extracts was studied using UV/VIS spectroscopy; the phytochemical composition of the birch outer bark ethanolic extract was investigated by HPLC-TOF/MS. The study of stability experiments has been carried out, which found that birch outer bark ethanolic extract compounds can be exposed to thermal and humidity degradation as well as exposure to β radiation, as extractants do not decompose in these degradation conditions. Acid or base degradation and oxidative degradation lead to partial degradation of the extracts. This kind of study for birch outer bark extract is not described and will serve as a basis for determining the expiry date of the extract containing cosmetic products and food additives, the choice of the required product packaging and storage conditions.

Anatomical explanations for acute depressions in radial pattern of axial sap flow in two diffuse-porous mangrove species: implications for water use.

Mangrove species have developed uniquely efficient water-use strategies in order to survive in highly saline and anaerobic environments. Herein, we estimated the stand water use of two diffuse-porous mangrove species of the same age, Sonneratia apetala Buch. Ham and Sonneratia caseolaris (L.) Engl., growing in a similar intertidal environment. Specifically, to investigate the radial patterns of axial sap flow density (Js) and understand the anatomical traits associated with them, we measured axial sap flow density in situ together with micromorphological observations. A significant decrease of Js was observed for both species. This result was accompanied by the corresponding observations of wood structure and blockages in xylem sapwood, which appeared to influence and, hence, explained the acute radial reductions of axial sap flow in the stems of both species. However, higher radial resistance in sapwood of S. caseolaris caused a steeper decline of Js radially when compared with S. apetala, thus explaining the latter's more efficient use of water. Without first considering acute reductions in Js into the sapwood from the outer bark, a total of ~55% and 51% of water use would have been overestimated, corresponding to average discrepancies in stand water use of 5.6 mm day-1 for S. apetala trees and 2.5 mm day-1 for S. caseolaris trees. This suggests that measuring radial pattern of Js is a critical factor in determining whole-tree or stand water use.

Absorption and translocation of cesium through Konara oak (Quercus serrata) bark

ABSTRACT Bark–wood translocation has been suggested as an important route for the contamination of trees via radiocesium in the initial stage of deposition. In this study, we investigated the cesium absorption through bark of mature Konara oak (Quercus serrata). Stable Cs (133Cs) was applied onto the bark at 1.2 m, and then after 8 weeks, the 133Cs concentration was determined in the outer bark, inner bark, sapwood, and heartwood of stem disks at several heights, as well as in the current-year leaves and branches from the tree tops. At the height of 1.2 m, the 133Cs concentration was significant higher in the sapwood of the treated trees than in those of the control trees. However, no difference was found in the 133Cs concentration in the heartwood of the treated and control trees not only in the wood above and below 1.2 m but also at 1.2 m. There was no significant difference in the 133Cs concentration of the current-year leaves and branches of the treated and control trees. Our results suggest that Cs absorption through bark may occur even in the dormant period of tree and the absorption is probably independent of cambial activities.

Variation in fire scar phenology from mixed conifer trees in the Sierra Nevada

Fire scar based studies have provided robust reconstructions of past fire regimes. The season in which a fire occurs can have considerable impacts to ecosystems but inference on seasonality from fire scars is relatively uncertain. This study examined patterns in the phenology of cambium formation and wounding responses in the five common mixed conifer tree species of the Sierra Nevada. The outer bark was shaved on 35 trees and individual locations within the shaved portions were wounded systematically by applying direct heat using a handheld torch. Most of the trees had not commenced annual ring development by the first burning treatment in late May. By the second treatment, scars were identified mostly within the early or middle earlywood, although variation was high compared with other treatment periods. By late October, all scars were recorded at the ring boundary. Although intra-ring scar positions generally followed a logical temporal pattern, there was high tree to tree variation such as Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) burned on 26 June induced scars in the early, mid, and late earlywood depending on the individual tree. This high variation makes it somewhat challenging to precisely assign past fire season to published fire history studies.

Integrative Analysis Based on HPLC-DAD-MS/MS and NMR of Bertholletia excelsa Bark Biomass Residues: Determination of Ellagic Acid Derivatives

Bertholletia excelsa Bonpl. (Lecythidaceae) is a South American tree worldwide known for providing the Brazil nuts. In the Amazon Region, B. excelsa is found in monocultures, integrating agroforestries and providing raw materials for food and timber industries. Through the application of an integrative analysis based on high-performance liquid chromatography coupled with diode array detector and tandem mass spectrometry (HPLC-DAD-MS/MS) and nuclear magnetic resonance (NMR) techniques, the present study showed that B. excelsa bark biomass residues contain large quantities of ellagic acid (EA) and its derivatives. Qualitatively, five compounds were characterized for the first time in this species. Quantitations were carried out to determine the total amount of these compounds in outer and inner bark tissues. A total of 4.96 and 44.09 g of EA derivatives per kg of dry residues was determined for the outer and inner barks, respectively. Among the EA derivatives, eschweilenol C, ellagic acid and valoneic acid dilactone were the main compounds. These results pointed B. excelsa barks as a valuable biomass residue with potential to be source of health-promoting compounds. Therefore, a potential raw material as source of valuable bioactive phenolic compounds is described herein.