Nirs tools for prediction of main extractives compounds of teak (Tectona grandis L.) heartwood

Biochemical and physiological process which occurred during heartwood formation have consequences on wood properties such as colour, natural durability and some mechanical properties. However, it is very time-consuming to take measurements of extractives contents. Teak has been reported to contain 1-hydroxy- 2-methyl-anthraquinone, 2-hydroxy-methyl-anthraquinone, 2-methyl- anthraquinone, lapachol, 1,4-naphthoquinone for the main compounds. In teak, natural durability is ascribed to extractives. Consequently, it's possible to estimate natural durability by measurement of extractives indirectly. For the purposes of selection for the production of improved varieties, the number of samples to be measured rapidly exceeds the capacity of a traditional laboratory. Near-infrared spectroscopy approach, based on spectral data and reference data, is a tool enabling many of the chemical properties of wood to be predicted and the number of laboratory measurements to be reduced exponentially. The issue here is a question of checking the effectiveness of NIRS tool to build models and predict the main extractive compounds of teak wood from Ivory Coast. We try to calibrate these chemical properties with Nirs spectral information measured on grounded wood. The results show the possible use of NIRS to predict total phenol content and some main extractive compounds of teak heartwood as tectoquinone, 2-hydroxymethylanthraquinone,Consequently, after verification on other sets of teak samples, which may or may not be included in the prediction model, NIRS can be used to predict extractive compounds accurately for a large number of samples, making it possible to estimate natural durability indirectly and to include these characteristics in the selection criteria for classifying wood and high throughput phenotyping. (Résumé d'auteur

Caractérisation moléculaire du M'jej, agent de dépérissement des cédraies marocaines

Le cèdre fournit un bois apprécié depuis plusieurs millénaires. Néanmoins, son importance économique reste limitée du fait de sa répartition géographique restreinte au bassin méditerranéen et à l'Himalaya. Cedrus atlantica occupe une place majeure parmi les espèces de ce genre, avec des peuplements très importants au Maroc. Le bloc du Moyen Atlas marocain (130 000 ha) est exposé à des maladies cryptogamiques, en particulier le "M'jej", qui diminue de 40% le rendement au sciage. Le M'jej provoque une pourriture fibreuse du bois de coeur. Parmi les nombreux genres et espèces fongiques décrits comme responsables du M'jej, tous sont synonymes soit de Phellinus chrysoloma, soit de P. pini. Identifiées suivant les caractères morphologiques, anatomiques et écologiques des carpophores, ces deux espèces seraient les principaux agents responsables du M'jej. Nos travaux de caractérisation moléculaire d'échantillons récoltés sur des arbres malades et la comparaison avec des séquences de référence montrent la proximité taxinomique de ces deux espèces, suggérant leur synonymie. (Résumé d'auteur

Accreditation : mutual benefits for research and industry

The wood preservation laboratory of the CIRAD had its first ISO 17025 accreditation from the COFRAC in 2006 for 5 standardized test procedures. The so called "first cycle" of its accreditation will be mid-2010. This laboratory is now accredited for 8 tests and is planning to increase the field of its quality management and accreditation. This poster describes how research projects, pre-normative research and industry impacted the quality management activities. (Résumé d'auteur

Natural durability of african Padauk and Niove comparaison of new trials and former data from the CIRAD database

African Padauk (Pterocarpus soyauxii) and Niove (Staudia kamerunensis) were tested in laboratory against Basidiomycetes. The results were calculated according to the requirements of EN 350-1 (1994) and XP CEN/TS 15083-1 (2006). Padauk samples showed a high durability and very small variations between trees and within tree. Niove presented a high durability, but with notable differences according to the calculation of the results. This paper is underlining the importance of the sampling, the test method, and the calculation of the results for the qualification of timber. This is of importance considering that the EN 350-2 standard is under revision and that different timbers (secondary species, plantation timbers,...) are available on the market. (Résumé d'auteur

Assessing the natural durability of teak wood by near infrared spectroscopy

Owing to its outstanding technological properties, teak (Tectona grandis Linn. f.) is one of the most preferred tropical timbers in the world. Some of its characteristics play a key role in defining the suitability of this timber species for specific end-uses. One of the most commonly cited characteristics of teak wood is its natural durability. It offers very good resistance to weather, termites, and decay, which means that it can be used externally without any treatment, increasing its commercial value. Like many characteristics, there is variability in this property, especially since the diversification of silvicultural practices and increase in plantation areas to meet market demand. Assessing natural durability is a tedious, complicated, and time-consuming procedure, and this explains why there are very few reports on variation in the natural durability of teak wood. One of the methods most likely to be adaptable to rapid measurements of wood is near-infrared diffuse reflectance spectroscopy (NIRS). MRS is widely used to identify compounds and to assess various material properties. This study evaluated the ability of MRS to assess the resistance of teak wood of different origins to fungi, in comparison with standard test methods. The best measurement strategy is discussed. The results prove that NIRS can predict resistance to different species of fungi, which use different schemes of attack. (Texte intégral