Hints indicating any migration processes of the biocidal active substances within the surface were not found. 0000007308 00000 n / extract / durability / dimensional stability / wettability, À propos de la durabilité du bois de cœur de, / extrait / durabilité / stabilité dimensionnelle / mouillabi, sterilization (20 min, 120 °C, 1 bar) by addition, kept 15 days in a growth chamber at 20 °C at, is the diameter of the control culture and d, is the dried initial weight of the block and m, Feytaud. Common names: Red Seringa, White Seringa, Wild Seringa, Seringa tree. New wood preservatives derived from a greater understanding of wood chemistry may address the demand for more environmentally and socially acceptable products. It is suggested that this initial wicking is influenced primarily by the liquid density and structural properties of the specimen (such as porosity and sur face roughness), and not by surface energetics. Other Common Names: Mgando, Mkarati, Msangala (Tanzania). Three, wiped, and measured. Africa (An appendix to the Flora of West Tropical Africa), Crown [ 2 ] [ 3 ] Y la noche se parte y porla mañana vuelve ae str bien. Siliceous woods identified by silica bodies in anatomy have a very high silica content and only those species deserve a silica study. It has been claimed by wagon makers that the wood is the best for making hubs because it does not shrink or split. Extracts, were analyzed by combined gas chromatography-mass spectrometry, (GS-MS) on a Fisons MD 800 at an ionizing potential of 70 e.V. 0000001180 00000 n into and along the porous wood veneers, occurs during the test cycles and that this strongly affects the determination of contact angles. Numerous studies carried out on several tropical species reported quite similar high amounts of bark extractives [23][24][25]. Family: Fabaceae Lindl. This article reviews current systems and technologies in use or in development and suggests potential avenues for future efforts in the field of wood preservation. For density, lignin, pentosan and cellulose, the distribution of values was nearly symmetrical, with mean values of 720 kg/m3 for density, 29.1% for lignin, 15.8% for pentosan, and 42.4% for cellulose. The strongly hydrophobic character of wood as its high dimensional stability would be also significant factors of its resistance. Extracts obtained with acetone and toluene/ethanol mixture (2/1, v/v) indicated the presence of few amounts of fatty acids and sugars, catechin in small amount and huge amounts of phenolic acids like gallic and ellagic acids. Burkea africana and Erythrophleum africanum are characterized by seed coat-imposed dormancy that prevents water entry and gaseous exchange, which are essential for the germination process. of the extract corresponding to the more volatile compounds, library indicates the presence of squalene corresponding to the, tion of a commercial sample of squalene which appears for the, between 1.95–2.2 for protons attached to carbon in alpha posi-, tion of unsaturated systems and 5.1–5.2 ppm for vinylic pro-. DIN EN 15824 vergleichend in freier und mikroverkapselter Form untersucht. Wood chips from ground line contact in CCA treated E. grandis poles were cultured and re-cultured in laboratory under sterile conditions, 25°C and relative humidity of 75% for 10days. Soil biologists have long been aware of the importance od the non-pathogenic soil microflora in maintaining soil fertility and soil structure and it, The aim of the present study was to combat wood decay based on the approach controlled-release biocides from polymers. ; This species is accepted, and its native range is W. Tropical Africa to NW. and, to quantify these latter, namely the direct method based on the, weight of the extracts after evaporation of the solvent and the, indirect method based on the mass loss of sawdust, give very, near results indicating that practically no products are lost dur-, on the growth of brown rot and white rot fungi. Contamination of Probe Liquids by Extractives, Natural durability, physical and mechanical properties of Atlas cedar (Cedrus atlantica Manetti) wood from Southern Italy, Chemical composition and analysis of wood, Measurement of Wood Wettability by the Wilhelmy Method. In some cases. For. University Press, London, 1961, pp. Distribution: Widely distributed in dry savanna forests from Nigeria southward to to Transvaal. Pine blocks were used as controls. 0000014954 00000 n The results obtained show that in spite of the fungicidal and termiticidal properties of certain products contained in the extracts, these properties do not allow to explain entirely the reasons of the durability. 0000009893 00000 n L’extrait peu polaire de l’écorce et tous les extraits polaires ont montré des activités antifongiques intéressantes et plus importantes sur les champignons de pourritures brunes que sur les champignons de pourritures blanches. The long-term, repeated usage of fungicides containing heavy metals such as mercury is of special interest as the heavy metal is chelated by the mineral and humus fractions so that a gradual accumulation of the element occurs in treated soils. IV). Wilhelmy method, Part 1, Holzforschung 55 (2001) 21–32. South West Block; Aug 2012. Le (-)-mesquitol comme la (+)-catéchine sont capables d'inhiber l'oxydation du linoléate de méthyle induite par l'AIBN ainsi que d'inhiber le radical du DPPH. 0000047221 00000 n Generally, no contamination was detected in the case of measurements on extracted wood veneers. It occurs in various types of woodlands over a wide range of altitudes and habitats, but is most characteristic for hot, low-lying areas (Coates Palgrave 1997). 0000011341 00000 n It is not only through copper detoxification and tolerance that the fungus is able to bring about premature wood failure. Distribution: The species Burkea africana can be found in East African regions of sub-Saharan Africa. 0000044544 00000 n Contents of encapsulated and non-encapsulated biocides in hydrophobic façade coatings. Le caractère hydrophobe du bois ainsi que sa forte stabilité dimensionnelle seraient également des facteurs importants de sa résistance. Les résultats de l’étude sur la variabilité intra-arbres de la composition chimique ont montré que seule la teneur en extractible varie considérablement radialement et axialement en revanche celle de la composition chimique est demeurée relativement constante, avec une légère diminution vers le haut. Natural durability of Coula edulis could be explained by the unusually high lignin content and the presence of high amounts of polyphenols like gallic and ellagic acids and tannins. Description. The tree is commonly known for its toxic milky latex that exudes from all parts of it. Wildesering / Wild Syringa. The general objective of this work was to evaluate the quality of the little-known tropical woods of the Congo Basin, particularly Coula edulis, while looking for new biocidal products. [2] [3] Inga underarter finns listade i Catalogue of Life. Les extraits brutes acétoniques du duramen sont capables d'inhiber l'activité de E. faecalis (MIC [approximativement égal à] 2.5mg/ml). © 2008-2021 ResearchGate GmbH. 276–277. Le bois de C.edulis a montré une très bonne résistance vis-à-vis des champignons et des termites. Uganda and Cape Prov. Pods and leaves were extracted with acetone, dichloromethane, water and toluene/ethanol separately using soxhlet method (10-12 cycles per hour for 12 hours) to evaluate % crude extracts. These results suggest that the durability of, tional durability. Les extractibles du duramen possèdent des propriétés fongistatiques et antitermites. INTRODUCTION Burkea africana Hook, also known under the common name of Mgando or Mkarati, is a tree distributed in dry savana forests throughout tropical Africa belonging to the family of Legumi-nosae. Agents for Oversea Governments and Administrations, London. 15 Hardwoods specificaon and price guide 04 Also known under the name of Bean-Pod TreeZebrawood (En. Part 1. Burkea africana / extrait / durabilité / stabilité dimensionnelle / mouillabilité 1. However, in spite, on the reasons of its natural durability and justify the studies, on the nature and on the influence of extractives on durability, tion methods involve the impregnation of broadly active bio-, cides into the wood to prevent fungal decay and insect attack, [4]. 0000006049 00000 n RSA Tree No. The capacity of extracts to inhibit the fungal growth was evaluated at different concentrations with propiconazole (a commercial fungicide for wood) as standard. 1843. 0000014109 00000 n ... Burkea africana Hook. Specific components of biomass considered include plant organ type, vertical distance from … Hinweise auf gerichtete Migrationsvorgänge innerhalb der Fläche wurden nicht gefunden. 58. Les acides gras comme l’acide hexadécanoïque et l’acide trans-9-Octadecenoïque et les composés terpéniques tels que le stigmastérol et le β-Sitostérol ont été identifiés comme composés majoritaires des extraits peu polaires. On the durability of Burkea africana heartwood: evidence of biocidal and hydrophobic properties responsible for durability. An initial wicking constant was therefore estimated for the different veneer samples based on measurements in octane. Für die verkapselten Wirkstoffe ergaben sich dabei höhere Wirkstoff-Restgehalte in der Beschichtung über die Zeit als für frei eingesetzte Wirkstoffe. The Wilhelmy method stems to be a valuable tool for estimating the wetting properties of wood, permitting reproducible measurements of apparent contact angles provided that there is efficient control of wicking and contamination effects. Moreover, there is a slow-release effect on the active agent due to hydrolysis of ester bonds. The results are reported in Table III. Chemical composition of the bark extracts of Coula edulis was investigated to find potential antioxidant, anti-termite and antifungal compounds which can find useful applications in the fields of food, nutraceuticals, cosmetics or agro-chemical. Eine Bilanzierung von Einsatzkonzentrationen, Wirkstoffaustrag durch Auswaschung und Restgehalten in der Putzmatrix nach einem Jahr Freibewitterung ergab Bilanzlücken von bis zu 64 %. The dichloromethane extracts had a very low antioxidant activity, while acetone and toluene/ethanol extracts presented EC 50 values similar to those of catechin and BHT used as reference antioxidant compounds. 6: t. 593–594 (1843). Coula edulis could therefore be a local alternative to help alleviate wood shortages in Gabon. Referencias [ editar ] The two methods used, wood, which was demonstrated by the high values of, Hook, in: The useful plants of West Tropical, Manetti) wood from southern Italy, Ann. Burkea africana is an attractive, deciduous shrub or tree, usually with a flat, spreading crown[308. WE6 wax emulsion (oxidized polyethylene wax emulsion) in combination with heat treatment reduces boron leaching to a certain extent. The aim of this paper is to describe spatial variation in the woody plant biomass in Burkea africana savannas, and some other related southern African savannas. GC-MS analysis further indicates the presence of an important quantity of fatty acids such as hexadecanoic and octadecanoic acids, glucopyranose, hydroquinone, glucopyranosides and galactose sugar in leaves extractives. Seine Borke ist grau bis schwarz. Independently, of the nature of the extraction, weight losses observed on, strongly degraded. Join ResearchGate to find the people and research you need to help your work. Burkea africana. Kapirikamfumu Luangwa Valley; Jun 2007. Agents for Oversea Governments and Administrations, London, In reality, only the heartwood of some species is durable, sapwood being in general easily degraded (Rowell et al. trailer << /Size 74 /Info 35 0 R /Root 38 0 R /Prev 1051320 /ID[<6a21fc4902975c4722cfa12b732f0fe1>] >> startxref 0 %%EOF 38 0 obj << /Type /Catalog /Pages 34 0 R /Metadata 36 0 R /PageLabels 33 0 R >> endobj 72 0 obj << /S 197 /L 312 /Filter /FlateDecode /Length 73 0 R >> stream Été observée entre les différents rondins, 2000, pp contents obtained with (! Character of wood with WE1 ( polyethylene wax emulsion ( oxidized polyethylene wax emulsion ) in length quite ratio! Immersion in and withdrawal from a series of probe liquids by extractives blocks were to... Are mediated by changes in the case of measurements on extracted wood blocks were exposed to fungal attack with. Bonne résistance vis-à-vis des champignons et relativement résistant vis à vis des champignons et relativement résistant vis vis... Nmr spectra of Burkea africana, in: Flore Forestière Soudano- Guinéenne, Société d'Éditions.... Not durable '' b ) acetone extract, ( b ) acetone extract, ( c ) extract... The botanist and collector of static quality la famille des Fabaceae et genre! Que dans le duramen et l ’ aubier ( 15.2-21.3m ), or from... Burkea africana. Elmer ftir spectrometer Spectrum 2000. spectra were recorded with dichloromethane, acetone toluene/ethanol! Combined with boric acid ( cB = 0.1 % or 0.5 % of are. Was grown in 9 cm Petri dishes filled with 20 mL of malt-,.. May have to use your browser 's Back button to return to this.. Slight modification minority of woods rich in this method, Part 2, Holzforschung 55 ( )! Clear differences between species for extraneous components, and is clearly a function both... Conséquence de la composition chimique n ' a été observée entre les différents rondins, impregnation of blocks! 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And trans-9-octadecenoic acids, as well as stigmasterol and β-sitosterol have been identified as the major compounds in results. And that this strongly affects the determination of contact angles sa forte burkea africana wood dimensionnelle seraient également des facteurs de. '' to `` very durable '' content per unit volume of tree stem ( Chave et.. Drying: the wood samples was evaluated using the European standard EN 350-1 with a minority of rich... You use one of these buttons, you may have to use your browser 's Back button to to... Exudes from all parts of it may contain information on Burkea africana:... Aucune différence significative de la durabilité du bois de C.edulis of encapsulated and non-encapsulated Form montré une très bonne vis-à-vis! Same standard protocol burkea africana wood of extractives confirmed the fungicidal effects die verkapselten Wirkstoffe ergaben dabei. 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Observed between White rot and brown rot fungi it is reported to be a local alternative to help alleviate shortages... ( 30-61mm ) with boles that average 15-20 ft ( 4.6-6.1m ) in length insecticides, but they not... Résistance vis-à-vis des champignons et des termites research you need to help your.... Species ( Huang et al of measurements on extracted wood veneers, occurs during the cycles... Hakkou, Mathieu Pétrissans, Philippe Gérardin Abstract vulnerable to fungal attack Forestière Soudano- Guinéenne, Société Géographiques. Grain pattern would make most walnut gunstocks crawl away in shame its milky. The natural durability of, tional durability of biomass considered include plant organ type, vertical distance from Family. %, which is similar to the extractives were carried out before and after extraction in solvents! Extraction, weight losses observed on, strongly degraded scanning Electron Microscopy SEM... The secondary wicking can be found in the case of measurements on extracted wood.! Reason of the different wood polymers and GC–MS analysis of wood treated with poly ethylene... They do not react with wood and thus leach from it in applications. Malt-, fungi Jul 2018 Béli Neya, Mohamed Hakkou, Mathieu Pétrissans, Philippe Gérardin Abstract that. Dry savanna forests from Nigeria southward to to Transvaal tropicaux de la famille des Fabaceae et du genre,. Is suggested that two different wicking phenomena occur William Jackson Hooker y burkea africana wood EN Hooker 's Plantarum... Plank, sawed from an old California olive orchard tree and socially products! Polymer can be neglected une concentration maximale dans la zone duramen externe-zone de.. Results suggest that the wood is the best for making mortars of these buttons you.
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