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This work focused on the upgrading of non-durable tropical wood species originating from fast-growing plantations of Costa Rica. Modification of such tropical woods with furfuryl alcohol, although ...

Acetylation of softwoods has been largely investigated to increase the dimensional stability and biological resistance of wood. However, the knowledge of this technology has not been applied to tropical hardwood species up to date. The objective of this work was to study the effect of acetylation on nine tropical hardwood species, from forest plantations in Costa Rica, by applying acetic anhydride in three different treatment times (1 h, 2.5 h, 4 h), as well as to evaluate this by Fourier-Transform Infrared Spectroscopy (FTIR). Results showed that weight percentage gain (WPG) of wood varied from 2.2 to 16.8%, withVochysia ferrugineaspecies showing the highest WPG, andGmelina arboreaandTectona grandisspecies exhibiting the lowest WPGs. Tropical woods such asEnterolobium cyclocarpum,Hieronyma alchorneoidesandSamanea samanexhibited statistical differences among treatment times, whereas the rest of the species studied showed no significant differences. In general, the most effective acetylation time was 2.5 h for all the species. The ratio of intensity (RI) from the FTIR spectra was greater at the 1732 cm−1, 1372 cm−1and 1228 cm−1peaks for all tropical species, associated with lignin. A good correlation between the RI of those peaks and WPG was found; the same was also found between all RIs and each other. Meanwhile, RI associated to the hemicelluloses and lignin (1592 cm−1and 1034 cm−1peaks, respectively) showed no correlation with WPG, nor between each other or with the other RIs. Furthermore, it was suggested that RI at 1732 cm−1(associated to acetyl groups C=O) can be considered as a reliable indicator of the degree of acetylation for tropical hardwood species. Finally, it was observed that tropical hardwoods having more suitable anatomical features, like larger vessel diameter, higher ray width and frequency, and lesser deposits such as gums and tyloses in the vessels, resulted in significantly higher WPGs.

This work aimed to evaluate the effect of the precipitation of CaCO3 via subsequential in-situ mineral formation based on a solution-exchange process of two solution-exchange cycles via impregnation with CaCl2 in ethanol and NaHCO3 in water. The effects were investigated in terms of the structure of the wood and the thermal, physical, mechanical, and decay resistance properties of nine species commonly used in commercial reforestation in Costa Rica. The thermogravimetric analysis results showed that the woods with the highest formation of CaCO3 showed a more pronounced signal at 200 °C in relation to untreated/wood; therefore, they were more thermostable. The fire-retardancy test showed that flame time in CaCO3/wood composites was longer than for untreated/wood in half of the species tested, presenting a positive effect of mineralization. Wood density, decay resistance, modulus of rupture (MOR), modulus of elasticity (MOE) in flexion, and MOR in compression were slightly affected by mineralization. Water absorption increased, but it had no negative effect on the dimensional stability. In general, mineralization can be a chemical treatment to increase the dimensional stability and fire resistance of hardwood species without modifying the wood’s physical and mechanical properties.

Magnetic wood is a composite material that achieves harmony between both woody and magnetic functions through the active addition of magnetic characteristics to the wood itself. In addition to showing magnetic characteristics, magnetic wood offers low specific gravity, humidity control and acoustic absorption ability. It has potential for broad applications in the fields of electromagnetic wave absorption, electromagnetic interference shielding, furniture, etc. This work reports on the synthesis of Fe

Tectona grandis (teak) is an important commercial tree species that is widely used in tropical dendrochronology due to the formation of climate-sensitive annual growth rings. However, young trees growing in plantation conditions exhibit poor ring visibility during the first years of growth, limiting the dendrochronology application. In the present study, we use x-ray densitometry to determine the wood density profile between and within annual rings and at the sapwood-heartwood boundary in trees from fast-growth plantations. The resulting wood density profiles (WDP) can be categorized as uniform, stable growth, unstable growth, and false. The annual ring boundaries were indistinct in trees less than 8 years old. In mature trees, the annual ring boundaries are more defined. In relation to the sapwood-heartwood boundary, the WDP showed a decrease in the wood density; however, this decrease is influenced by the annual ring boundary when the two boundaries coincide. The identification of annual rings in trees growing in fast-growth plantations should be combined with X-ray densitometry and visual identification if wood density data are necessary for deriving other analysis, as climate change, from annual ring.

Se analizó de forma perceptual la transferencia de conocimiento en tecnología de la madera en instituciones educativas estatales de Costa Rica. Se realizaron capacitaciones activo-pasivas en temas de secado, preservado y calidad de la madera, llevando a cabo tres evaluaciones de aprendizaje (precurso, postcurso y 30 semanas luego del postcurso). Con estas se valuó la percepción, conocimiento adquirido y limitaciones de los sistemas empleados. Se obtuvo una gran similitud entre las temáticas de secado y preservado con conocimientos previos superiores al 65 %, aprendizajes del 85 % y retenciones de conocimiento del 75 %; caso contrario se evidenció con la temática de calidad, la cual presentó un conocimiento previo del 20 %, aprendizaje del 83.5 % y retención del 75.6 %; los temas de secado y preservado mostraron la mejor percepción, considerados como simples, aplicables, útiles y entendibles; mientras que el tema de calidad se consideró complicado, complejo, inaplicable pero útil. Finalmente, se encontró que el aprendizaje de secado y preservado debe ser una combinación de 50 %-50 % entre teoría-práctica; mientras la calidad debería ser 25 %-75 % teoría-práctica.

Resumen La mosca blanca (Bemisia tabaci Genn.) es una especie plaga de importancia económica, ampliamente distribuida en el mundo y causante de pérdidas cuantiosas en la producción agrícola. Su combate suele basarse en aplicaciones repetitivas de insecticidas químicos, que producen contaminación ambiental y generan resistencia en las poblaciones de los insectos. Este trabajo tuvo como objetivo evaluar la actividad insecticida de nueve extractos vegetales en adultos de B. tabaci, bajo condiciones experimentales in vitro. Se realizaron bioensayos de toxicidad con los extractos etanólicos de cada planta a una concentración de 5000 mg/L, para determinar el de mejor desempeño. Las especies vegetales utilizadas fueron Enterolobium cyclocarpum (hojas y corteza), Lippia graveolens (hojas), Ruta graveolens (hojas), Adonidia merrillii (hojas y frutos), Annona muricata (semillas), Curcuma longa (raíz) y Zingiber officinale (raíz). El más tóxico fue el extracto de R. graveolens, el cual se fraccionó por cromatografía de columna con tres solventes de polaridad creciente: isopropanol: diclorometano (8:2), etanol 96% y agua. Finalmente se realizaron bioensayos con las tres particiones fitoquímicas para determinar su actividad y lograr una aproximación al tipo de compuestos responsables de la actividad tóxica. La fracción menos polar (isopropanol: diclorometano (8:2)) fue la que ocasionó la mayor mortalidad. La investigación buscó generar información para el desarrollo de métodos de combate alternativos contra la plaga en estudio, teniendo como presupuesto que los extractos vegetales son una opción promisoria para el desarrollo de bioinsecticidas más seguros para el medio ambiente y la salud humana. Abstract The whitefly Bemisia tabaci Genn. is a pest. It causes economic losses in crop production and it is distributed worldwide. The combat against it is usually based on repetitive applications of chemical pesticides, resulting in environmental contamination and genetic resistance of insect populations. This research was carried out with the objective of evaluating the insecticidal activity of nine plant extracts in adults of B. tabaci, under in vitro experimental conditions. Toxicity bioassays with the ethanolic extracts of each plant at a concentration of 5000 mg/L were tested to determine the one with the best performance. The plant species used were Enterolobium cyclocarpum (leaves and bark), Lippia graveolens (leaves), Ruta graveolens (leaves), Adonidia merrillii (leaves and fruits), Annona muricata (seeds), Curcuma longa (root) and Zingiber officinale (root). The most toxic extract was R. graveolens; it was fractionated by column chromatography with three solvents of increasing polarity: isopropanol: dichloromethane (8:2), ethanol 96% and water. Finally, bioassays were carried out with the three phytochemical partitions to determine their activity and to approximate to the type of compounds responsible for the toxic activity. The least polar fraction (isopropanol: dichloromethane (8:2)) was the one that caused the highest mortality. The research sought to provide a basis for the creation of alternative control methods against the pest in study, under the assumption that plant extracts are a promising option for the development of bio-insecticides safer for the environment and human health.

To elucidate the development of heartwood, bark, sapwood, pith and specific gravity of wood in fast-growing teak (Tectona grandis) plantations in Costa Rica, we sampled three trees in each of 55 plantations and modelled each variable with age, site and different tree heights. Age and stand density of plantations were significant correlated with stem diameter at breast height and total height of the tree. Formation of heartwood was initiated at the age of 4-year-old and increased in direct proportion with age. The age of plantation had a significant relationship with stem diameter at breast height, heartwood percentage, sapwood thickness, sapwood percentage, percentage of bark, pith diameter and percentage, and specify gravity. The model for these tree parameters was model with these parameters as dependent variable and in relation to age as independent variable.

Tectona grandis is the second most important species for reforestation in Costa Rica, and any improvement in its industrialization process is important, especially the drying process. Lumber obtained from a plantation of 12-year-old T. grandis trees was used to evaluate three drying schedules that include integrated steaming processes to determine the combined effect of the steam-drying system on the dried lumber. The variations in the moisture content (MC) and drying rate (DR) with drying time (DT) both before and after the steaming process were modeled mathematically for boards that have a flat and quarter grain pattern. For both types of boards that were dried with and without steaming, a relationship between MC and DT was observed. There was inflexion at 40%, and two mathematical models were computed. Additionally, the relationship between DR and DT for boards with flat and quarter grain patterns was not affected by the steaming process, and an inflection point was observed at 30 h (40% MC for...

Aim of study: Plantations are threatened by an emerging disease called “Gmelina death disease”. The objective of this study was measured the incidence and severity of this disease and were correlated with the characteristics of the plantations, micro- and macronutrients in the soil and climatic parameters.Area of study: The present study evaluated 16 symptomatic fast-growth plantations of different age in Costa RicaMaterial and methods: Fungi were identified from xylem of infected trees. Incidence and severity was measured and correlated with the characteristics of the plantations, micro- and macronutrients in the soil and climatic parameters. Root condition and the quality (specify gravity, mechanical and decay resistance and chemical compositions), of the wood of symptomatic and asymptomatic trees were compared.Main results: Three fungal species (Chaetomella raphigera, Fusarium solani and Rhizomucor variabilis) were identified from diseased samples. Clay content in the soil profile from 10-20 cm deep explained a significant proportion of the variation in the incidence and severity of the disease, and stand density was related to severity. Although two climatic variables, Holdridge’s potential annual evapotranspiration and Thornthwaite’s potential evapotranspiration, showed a relationship between the incidence in the trees and symptoms of the disease. Infected wood turned black in symptomatic trees. Specify gravity and mechanical resistance of infected wood decreased, whereas its natural durability was unaffected. Changes were observed in the quantities of Mg, Fe, Ca, K and Zn in infected wood.Research highlights: Gmelina plantations established in sites with high stand densities and high contents of clay increase susceptibility to this disease.

The influence of climatic and site fertility conditions affect wood quality from fast growing trees. The change in tree diameter, thickness of sapwood, heartwood percentage and bark and pith tissue, physical and mechanical properties, resistance to termite attack and the presence of drying defects on lumber boards were evaluated. Four teak trees (Tectona grandis L.f.) from fast growing plantations in Costa Rica were selected for the study. Teak trees of 11 years old growing in two climatic conditions and two fertility types (high and low fertility) in Costa Rica were studied. The results showed that tree diameter, sapwood thickness, pith diameter and its percentage were higher in the climate with more rainfall and greater fertility. However, the percentage of heartwood and bark were higher at low fertility sites with less rainfall. It was also observed that only sites with low fertility produce modifications in specify gravity, fiber saturation point, initial moisture content, MOR in flexion in green and dry condition, MOE in bending and resistance to termite attack. Incidence and magnitude of defects increased with drying, and were mainly affected when wood comes from younger trees from high fertility sites and growing in tropical moist forest climate. © 2015, Indian Academy of Wood Science.

This study details information about physical, chemical and mechanical properties, drying, preservation and workability of wood from Cordia alliodora, Dipteryx panamensis, Enterolobium cyclocarpum, Hieronyma alchorneoides, Samanea saman and Vochysia ferruginea trees, growing in forest plantations in Costa Rica. Variation of the general properties in relation to height showed that heartwood percentage decreases, bark percentage increases and pith percentage is not affected. Dipteryx panamensis showed both the highest values for specific gravity and the highest mechanic resistance. Both chemical properties and extractives presence were different among species. Heartwood was not possible to preserve in any of the species, though sapwood was. Penetration varied from partial irregular or vascular in the species. The highest durability was for Hieronyma alchorneoides and Vochysia ferruginea, species classified as of high durability. Finally, all species had good performance in the workability tests. The previous results indicate that these species, used for trading reforestation in Costa Rica, have acceptable characteristics to be commercialized and used in wooden products., El presente estudio detalla información de las propiedades físicas, químicas, mecánicas, de secado, preservación y trabajabilidad de la madera de Cordia alliodora, Dipteryx panamensis, Enterolobium cyclocarpum, Hieronyma alchorneoides, Samanea saman y Vochysia ferruginea proveniente de plantaciones forestales en Costa Rica. La variación de las propiedades con respecto a la altura mostró que el porcentaje de duramen disminuyó, el porcentaje de corteza aumentó y el porcentaje de médula no se vio afectado por la altura del árbol. Dipteryx panamensis presentó los valores de peso específico más altos, por lo tanto, también presentó los valores de resistencia mecánica más altos. No fue posible preservar el duramen en ninguna especie, pero la albura sí y su penetración varió de parcial irregular o vascular en las especies. La mayor durabilidad se presentó en Hieronyma alchorneoides y Vochysia ferruginea, especies clasificadas como de alta durabilidad. Finalmente, todas las especies presentaron buen comportamiento en las pruebas de trabajabilidad. Los resultados anteriores indican que estas especies, utilizadas en la reforestación comercial de Costa Rica, poseen características aceptables para ser utilizadas en la comercialización y uso en productos de madera.

Quorum sensing (QS) activity in Ophiostoma fungi has not been described. We have examined the growth conditions on the control of dimorphism in Ophiostoma floccosum, an attractive biocontrol agent against blue-stain fungi, and its relationship with QS activity. In a defined culture medium with L-proline as the N source, a high inoculum size (10(7) c.f.u. ml(-1)) was the principal factor that promoted yeast-like growth. Inoculum size effect can be explained by the secretion of a QS molecule(s) (QSMs) responsible for inducing yeast morphology. QSM candidates were extracted from spent medium and their structure was determined by GC-MS. Three cyclic sesquiterpenes were found. The most abundant molecule, and therefore the principal candidate to be the QSM responsible for yeast growth of O. floccosum, was 1,1,4a-trimethyl-5,6-dimethylene-decalin (C15H24). Other two compounds were also detected.

Aims: For Ophiostoma (Ceratocystis) ulmi, the ability to undergo morphological change is a crucial factor for its virulence. To gain an understanding of quorum-sensing activity in O. ulmi as it relates to yeast-mycelium dimorphism control, this study examines the effects of branched-chain amino acids as well as their fusel alcohols and fusel acids as quorum sensing molecules. Methods and Results: In a defined medium containing glucose, proline and salts, O. ulmi grew as yeasts when the culture was inoculated with a high density of spores (2 × 107 CFU ml−1) and as mycelia when inoculated with a low spore density (4 × 105 CFU ml−1). The cultures displaying yeast morphology secreted a quorum-sensing factor that shifted the morphology from mycelia to yeast. This quorum-sensing molecule was lipophilic and extractable by organic solvents from the spent medium. Using GC/MS analysis, it was determined that the major compound in the extract was 2-methyl-1-butanol. A similar effect was observed when the branched-chain amino acids (fusel alcohol precursors) were used as the nitrogen source. E, E-farnesol had no effect on the morphology of O. ulmi. Conclusions: Addition of the branched-chain amino acids or one of the compounds detected in the spent medium, 2-methyl-1-butanol or 4-hydroxyphenylacetic acid, or methylvaleric acid, decreased germ tube formation by more than 50%, thus demonstrating a quorum sensing molecule behaviour in O. ulmi cultures. Significance and impact of the study: This study presents advances in the investigation of dimorphism in O. ulmi, complementing the existing scientific basis, for studying, understanding and controlling this phenomenon.

Los hongos del genero Ophiostoma promueven la ocurrencia de la mancha azul en madera de coniferas, afectando significativamente la calidad en los productos de apariencia. Para la prevencion de la mancha azul se han empleado productos quimicos de diferente naturaleza. El control biologico de la mancha azul con cepas albinas del genero Ophiostoma aparece como una alternativa de promisorio potencial. Algunos de estos hongos cuando cultivados en medio liquido presentan un crecimiento dimorfico, con alta proporcion de micelio, que dificulta su utilizacion. El dimorfismo, transformacion reversible de las morfologias levadura y micelio, es controlado por factores quimicos y del entorno. En esta investigacion mediante la aplicacion de un diseno factorial completo de dos niveles, se estudio el efecto de cuatro variables operacionales sobre el crecimiento levaduriforme de la cepa albina PcF2A29 de la especie Ophiostoma piceae (Munch) H. & P. Syd., creciendo en medio de cultivo liquido complejo. Los resultados mostraron que el tamano del inoculo, la temperatura y la interaccion tamano del inoculo-temperatura tuvieron un efecto estadistico significativo sobre el crecimiento levaduriforme de la cepa albina PcF2A29de la especie O. piceae. De estas variables, el tamano del inoculo resulto ser el efecto mas importante y explico el 53% de la variabilidad observada. Estos resultados sugieren por primera vez, en la especie O. piceae, la existencia de un mecanismo de deteccion del quorum asociado a la variable tamano del inoculo.

La présente étude vise à établir les variations du duramen (pourcentage, diamètre, rayon, volume) rapportées à la hauteur des arbres et à l’épaisseur de l’aubier, ainsi que l’âge de début de formation du duramen et sa hauteur maximale pour les arbres de l’essence Tectona grandis. Les résultats de l’échantillonnage de seize plantations réparties dans différentes zones du Costa Rica, âgées de 2 à 22 ans, montrent que l’aubier est plus épais entre 2 et 10 ans d’âge qu’entre 10 et 22 ans. La formation du duramen commence à la base des arbres âgés de 2 à 3 ans, mais il n’apparaît à hauteur de poitrine qu’à partir de 3 à 4 ans. Le duramen disparaît à une hauteur allant de 0 à 90 % de la hauteur totale selon l’âge de l’arbre. Enfin, des modèles statistiques prédictifs ont été développés pour l’épaisseur de l’aubier et pour le rayon, la hauteur maximale et le pourcentage du duramen, en se basant sur le modèle Y = K0 + K1*(épaisseur de l’aubier) + K2*(hauteur relative de l’échantillonnage) + K3*(diamètre à hauteur de poitrine) + K4*(âge de l’arbre). Ces modèles indiquent des coefficients de détermination de 70 %, 90 %, 95 %, 73 % et 31 %, respectivement.

Wetwood is commonly reported in temperate species but not so in tropical species. In an old Gmelina arborea Roxb. plantation, wetwood was identified by a darker colour compared with the rest of heartwood; by a higher moisture content (average 182%); and a lower specific gravity (0.34, compared with 0.38 for sapwood and heartwood). Tangential shrinkage was 3.7%, which was significantly higher than that of heartwood and sapwood. Radial shrinkage was not significantly different between wetwood and sapwood, but it was significantly greater (2.6%) in wetwood than in heartwood (1.8%). Wetwood had a significantly higher pH than normal wood, but ash composition was similar to that of normal wood, with the exception of the amounts of iron and potassium. Wetwood and sapwood were less decay resistant than heartwood. Wetwood required less time than heartwood to reach equilibrium moisture content, but more time than sapwood. The tangential and longitudinal diffusion coefficients of wetwood were significantly higher than those of heartwood and lower than those of sapwood. In the radial direction sapwood showed a faster drying rate than wetwood but there was no significant difference between wetwood and heartwood.

Artículo científico Trametes versicolor and Pleurotus ostreatus were used for the biopulping from pineapple leaf fiber (PALF). PALF substrate was subjected to T. versicolor for 2 to 6 weeks and to P. ostreatus for 4 to 8 weeks. The yields, holocellulose and lignin contents, and extractives in ethanol-toluene mixture and in sodium hydroxide (NaOH) solution were evaluated. Fourier transform infrared spectroscopy (FTIR) spectra, thermogravimetric analysis (TGA), and color studies by L*a*b* systems were used for sample analysis. The results showed that the pulp yield was 55% to 70% with P. ostreatus and 35% to 50% with T. versicolor. Longer colonization periods increased the amount of holocellulose and decreased the amount of lignin and extractives in ethanol-toluene and NaOH solution. TGA showed an increase in intensity associated with cellulose, and the observed inflexion was attributed to lignin, which showed a tendency to fade. The FTIR spectrum showed high intensity between 3100 cm-1 and 3600 cm-1 (cellulose) and decreased intensity at 1730 cm-1 (lignin). For both fungi, the pulp color produced an increase in L* color parameter and decreased in yellowness, while little variation was observed in redness. The most appropriate colonization period was 5 weeks for P. ostreatus and 4 weeks for T. versicolor.

Costa Rica has successfully planted various forestry species for wood production. However, the use of their wood is limited, due to poor knowledge about their chemical properties, air-dry, preserved and workability performance. The present study details information of these properties for the species: Alnus acuminata (Aa), Acacia mangium (Am), Bombacopsis quinata (Bq), Cupressus lusitanica (Cl), Swietenia macrophylla (Sm), Terminalia amazonia (Ta), Terminalia oblonga (To) and Vochysia guatemalensis (Vg). Among the results obtained, it was found that the wood of these species is in general slightly acidic, except Bq, which presented tendency to be basic. Different species show considerable variability in the content of holocellulose, lignin and extractable micronutrients. Regarding micronutrients, and in relation to other species it was found a high percentage in Vg. The use of boron as a preservative, may be applied in the 8 plantation species. The presence of heartwood in some species made it not possible to be preserved by the vacuum-pressure method, but the sapwood was possible to preserve in all species. The drying rate increased with increasing board thickness and drying time was different among species. The fastest drying rate was found in Ta and Am, followed by Sm, To, Aa and Cl with intermediate values and Vg with the slowest air-drying rate. Am, Bq, Cl, Sm and To present from excellent to good planing, sanding , drilling and molding, but Ta, Bq, Aa and Vg, especially Aa and Vg, in the workability operations were catalogued as poor or very poor quality.Evaluación de la composición química, secado al aire, preservación y trabajabilidad de ocho especies de rápido crecimiento en plantación de Costa RicaEn Costa Rica se han plantado con éxito varias especies forestales para la producción de madera. No obstante, el uso de la madera es limitado debido al poco conocimiento acerca de sus propiedades químicas, secado al aire, preservado y trabajabilidad. En el presente estudio se detalla información de esas propiedades para las especies: Alnus acuminata (Aa), Acacia mangium (Am), Bombacopsis quinata (Bq), Cupressus lusitanica (Cl), Swietenia macrophylla (Sm), Terminalia amazonia (Ta), Terminalia oblonga (To) and Vochysia guatemalensis (Vg). Dentro de los resultados obtenidos, se encontró que la madera presenta un pH ligeramente ácido, a excepción de Bq, con tendencia a ser básica. Las diferentes especies muestran una considerable variabilidad en el contenido de holocelulosa, lignina, extraíbles y micronutrientes; con respecto a los micronutrientes, y en relación con las otras especies se encontró un alto porcentaje en Vg. El uso de boro como preservador, puede ser aplicado en las 8 especies de plantación. Las especies con presencia de duramen no fue posible preservarlas con el método vacío-presión; sin embargo, la albura sí es posible de preservar en todas las especies. El tiempo de secado incrementa con el incremento de espesor de la tabla y presenta variación entre especies. El menor tiempo de secado se encontró para Ta y Am, seguido por Sm, To, Aa y Cl, con valores intermedios y Vg con el secado al aire más lento. Am, Bq, Cl, Sm y To presentan de excelentes a buenas propiedades de cepillado, lijado, taladrado y moldurado, pero el resto de las especies (Ta, Bq, Aa and Vg), en especial para Aa y Vg, en las operaciones de trabajabilidad son catalogadas como de mala o muy pobre calidad.

Blue stain in Pinus radiata D. Don wood is predominantly caused by Ophiostoma genus fungi. Stained wood causes significant economic losses to forestry and timber industries. Currently, different chemical fungicides are used to prevent the occurrence of blue stain fungi. However, recent reports have questioned the environmental friendliness of these fungicides. For this reason, the use of biological control, in particular with albino strains of the Ophiostoma genus, appears to be an environmentally safe and a technically feasible alternative to work with. The potential field application of this technology would use a formulation containing the albino fungus-the bioactive ingredient- in its yeast like form. However, some Ophiostoma strains cultures present a marked filamentous morphology in liquid culture medium, affecting the efficiency in the production of the bioactive ingredient. The hypothesis of this work presumed the possibility to control the morphology of Ophiostoma cultures, through the modification of growth conditions in liquid medium. The effect of inoculum size, growth temperature and agitation rate on the morphology of PcF2A29 Ophiostoma piceae and FlF1A55 Ophiostoma floccosum albino strains in liquid culture medium, was studied. A 23 factorial design was employed. The results showed that the initial inoculum size had a statistically significant effect on yeast-like growth morphology in both strains, whereas the temperature only produced a significant effect in PcF2A29 O. piceae strain. Blue stain in Pinus radiata D. Don wood is predominantly caused by Ophiostoma genus fungi. Stained wood causes significant economic losses to forestry and timber industries. Currently, different chemical fungicides are used to prevent the occurrence of blue stain fungi. However, recent reports have questioned the environmental friendliness of these fungicides. For this reason, the use of biological control, in particular with albino strains of the Ophiostoma genus, appears to be an environmentally safe and a technically feasible alternative to work with. The potential field application of this technology would use a formulation containing the albino fungus-the bioactive ingredient- in its yeast like form. However, some Ophiostoma strains cultures present a marked filamentous morphology in liquid culture medium, affecting the efficiency in the production of the bioactive ingredient. The hypothesis of this work presumed the possibility to control the morphology of Ophiostoma cultures, through the modification of growth conditions in liquid medium. The effect of inoculum size, growth temperature and agitation rate on the morphology of PcF2A29 Ophiostoma piceae and FlF1A55 Ophiostoma floccosum albino strains in liquid culture medium, was studied. A 23 factorial design was employed. The results showed that the initial inoculum size had a statistically significant effect on yeast-like growth morphology in both strains, whereas the temperature only produced a significant effect in PcF2A29 O. piceae strain.

Zn-EDTA degradabilty by catechol-driven Fenton reaction was studied. Response surface methodology central composite design was employed to maximize this complex degradation. Theoretical speciation calculations were in good agreement with the experimental results. Fenton and Fenton type treatments are typically thought to be applicable only in the highly acidic range, representing a major operational constraint. Interestingly, at optimized concentrations, this CAT-driven Fenton reaction at pH 5.5 achieved 100% Zn-EDTA degradation; 60% COD and 17% TOC removals, using tiny amounts of CAT (50 µM), Fe(III) (445 µM) and H2O2 (20 mM) with no evident ferric sludge.

International audience; Wood colour of Tectona grandis produced from fast-growth plantations is highly variable and the causes of this variation are relatively unknown.* With the purpose of understanding the colour variation, different fast-growth plantations were sampled with different growth rates, tree ages, and sites.* Wood colour was measured with a CIELab system, where three variables are estimated: coordinate L* for lightness, coordinate a* defines redness and coordinate b* defines yellowness.* Results showed only a negative correlation between L* and a*. L* and a* were negatively and positively respectively correlated with pith distance in heartwood, but not for b*. No correlations were found between L* and b* in sapwood and plantation characteristics, while a* was positively correlated with age and height of tree and growth rate. In heartwood, tree age and diameter at breast height were correlated with all colour parameters, but tree height and plantation density were correlated with a* and b*. Cluster site had correlation with L*. Multiple correlation analysis showed that the heartwood is increasing darker (L*) and redder (a*) when the trees are older and bigger. Correlation coefficient shown that sapwood and heartwood with lighter colour (L*) is less resistance to fungal attack, but redness colour (a*) increasing decay resistance.; Il y a une grande variabilité de la couleur du bois de Tectona grandis produit à partir de plantations à croissance rapide et les causes de ces variations sont relativement inconnues.* Pour comprendre l'origine des variations de couleur nous avons échantillonné dans des plantations à croissance rapide qui diffèrent entre elles en termes de vitesse de croissance, d'âge et de site.* La couleur du bois a été mesurée avec le système CIELab qui permet la mesure de trois variables colorimétriques: la luminance L* allant du noir au blanc, a* et b* allant respectivement du vert au rouge et du bleu au jaune.* Les résultats montrent une corrélation négative entre L* et a*. Dans le bois le cœur il y a une corrélation négative entre L* et la distance à la moelle et une corrélation positive entre a* et la distance à la moelle: aucune corrélation n'apparaît pour b*. Dans l'aubier, on ne trouve aucune corrélation entre L* et b* et les caractéristiques des plantations. Cependant a* est corrélé positivement avec l'âge, la hauteur et la vitesse de croissance des arbres. Dans le bois de cœur, l'âge et le diamètre à 1,3 m des arbres sont corrélés avec les trois coordonnées chromatiques mais la hauteur des arbres et la densité de plantation sont corrélées avec a* et b*. Il y a une corrélation entre le site et L*. On montre que le bois de cœur est d'autant plus sombre et rouge que les arbres sont plus vieux et plus gros. Les corrélations obtenues montrent que les bois d'aubier et de cœur qui sont les plus clairs résistent moins bien aux attaques fongiques et que les bois de tendance plus rougeâtre ont une meilleure résistance aux pourritures.

The color of Tectona grandis wood is an attribute that favors its commercialization, however, wood color from fast-growth plantation trees is clear and lacks uniformity. The aim of this work is to characterize steamed teak wood by means of the Fourier transform infrared spectroscopy (FTIR) and [Formula: see text] color systems. Two moisture conditions (green and 50%) and two grain patterns (flat and quarter) of boards were analyzed through the application of different steaming times (0, 3, 6, 9, 12, 15 and 18[Formula: see text]h). The FTIR results showed that the bands at 1158, 1231, 1373 and 1419[Formula: see text]cm[Formula: see text] did not show any change with steaming, whereas the bands at 1053, 1108, 1453, 1506, 1536, 1558, 1595, 1652, 1683, 1700 and 1733[Formula: see text]cm[Formula: see text] presented a decrease in the intensity with the steaming time. The band at 1318[Formula: see text]cm[Formula: see text] was the only one that increased. Lightness ([Formula: see text]) was the most affected parameter, followed by yellowness ([Formula: see text]), while redness ([Formula: see text]) showed the smallest change. Surface color change ([Formula: see text]) presented the lowest value between 3[Formula: see text]h and 6[Formula: see text]h of steam-drying in the boards with flat grain, whereas for boards with quarter grain, the smallest [Formula: see text] value was obtained after 18[Formula: see text]h of steaming.

The objective of this study was to show the radial variation of some anatomic characteristics, wood density and natural durability of teak (Tectona grandis L.F.) growing in Costa Rica. Samples of trees 13 years old were obtained from two growing sites (high and low growing) of plantations established in a humid tropical climate (CHT) and dry tropical climate (CST). The variables measured of the fibers as well as for the rays were not affected by the climate or the type of growing site, except for the length of the fibers. The fibers of teak wood from the best growing site were significantly larger. Vessels were found with a greater frequency for the CST but mostly solitary in comparison with the CHAverage density, maximum density and the variation within the ring presented a light higher magnitude for the CSThe quality of the growing site did not affect these variables. The resistance of fungus attack was similar in the area of heartwood near the pith compared to the heartwood near the sapwood for all the conditions evaluated. Nevertheless, it was observed in some trees a similar resistance of fungus attack for areas of sapwood compared to similar areas of heartwood. Con el objetivo de mostrar la variación radial de las características anatómicas, de densidad normal y de durabilidad natural de la madera de Tectona grandis L.f. creciendo en Costa Rica, se muestrearon plantaciones de 13 años procedentes de dos regiones con clima diferente: clima húmedo tropical (CHT) y clima seco tropical (CST). En cada una de ellas se analizaron dos tipos de sitios con diferente fertilidad: bueno (SB) y malo (SM). Se encontró que las fibras y los radios no fueran afectados por el tipo de clima o calidad de sitio, a excepción de la longitud de la fibra que sí fue afectada. Se encontró que CST produce mayor frecuencia de vasos, pero en su mayoría solitarios en relación al CHT, la densidad normal promedio, máxima y su variación dentro del anillo, presentan magnitudes mayores en CST que CSH. La calidad de sitio no afectó estas variables. La resistencia al ataque de hongos fue similar en el duramen próximo a la médula y el duramen próximo a la albura para los dos tipos de clima y las calidades de sitio. No obstante, se observó que en algunos árboles la resistencia al ataque de los hongos del duramen fue similar a la albura.