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Information of the biogeography and severity of attack provoked by wood boring species in European coastal waters was surprisingly scarce. Two of the outstanding questions that this work tried to answer were: which wood boring species occur in European coastal waters and what is the severity of their attack at each site. Therefore, a number of sites - as far north as Iceland and as far south as Turkey - were investigated. In addition three important European wreck sites located in the Netherlands, Germany and Finland were also investigated for species of wood borers present and severity of their attack. Pinus sylvestris panels were used as baits at each test site. At the wreck sites panels of recent cut oak and archaeological oak were also deployed. Wood borers that recruited to the panels were identified to the species level. The evaluation of the severity of attack in the test panels was based on X-rays of the panels and visual assessment under a stereo microscope. The rates varied from 0, no attack, to 4, panels destroyed, according to the categories described in EN 275 (1992). Six species of wood boring Bivalvia were found in the test sites. The most widely distributed species in northern Europe was Teredo navalis occurring in nine of the 15 sites surveyed. In southern Europe, Lyrodus pedicel/atus was clearly the dominant species in all the sites, except in the Black Sea where the sole bivalve species was Teredo navalis. Other bivalve species were more restricted in their distribution, occurring in only one or two of the sites: Psiloteredo megotara, Nototeredo norvagica, Teredo bartschi and Bankia carinata. In Iceland, the attack in test panels was provoked by Limnoria Iignorum (Isopoda: Crustacea). This species occurred only in the northernmost sites: Iceland, Sweden, Norway and Netherlands. Limnoria tripunctata, on the other hand, was found in the southernmost sites, Portugal and Turkey. Limnoria quadripunctata was found only in Langstone Harbour, England. Lyrodus pedicel/atus, Teredo navalis and Limnoria tripunctata were the most destructive species in this study. Complete failure of the wood panels occurred in Sweden, Netherlands, England, Croatia, Portugal and Turkey. No signs of boring activity were found in the Gulf of Riga, probably due to the very low salinity of its waters (0.2 to 3.75 PSU). The use of preservatives for use in the marine environment has been subject to ever increasing restrictions. In addition, naturally durable species of wood for use in maritime construction are becoming increasingly difficulty to obtain, due to the pressure imposed by the governments. The test of new timbers according to the five-year test period specified in EN 275, is too long a period for screening tests to be economically viable. Thus, in this study, laboratory screening tests, using Limnoria quadripunctata as the test organism, were optimised. The optimisation of the tests involved the investigation of the optimum conditions of temperature and light for Limnoria quadripunctata. The screening tests were then used to assess the durability of a large number of lesser utilised timber species and chemically modified wood for their potential for use in the marine environment. In all tests, the durability was assessed by measuring the production of faecal pellets by the crustacean Limnoria quadripunctata under forced feeding conditions over a fifteen-day period. The number of pellets produced by animals feeding on Scots pine sapwood, which is nondurable, was used as a basis for comparison. Lower pellet production rates and higher mortality rates were taken as measures of durability. The Ghanaian and Brazilian timbers balau, bompagya and jatoba had an antifeedant effect in L. quadripunctata and the water-soluble extractives produced by these timber species caused enhanced mortality on test organisms. Timbers such as ayan, Bruguiera, louro gamela, acariaquara, favinha prunelha and uchi torrado and their leachates were toxic to Limnoria quadripunctata. Treatments of PBTC with urea 1 were resistant to wood borers in laboratory tests and in the field trial. Wood treated with one of the formulations of PBTC with urea 2 and urea 2 alone showed also enhanced resistance against L. quadripunctata. However, none of the wood modifications mentioned above were leach-resistant. To be of practical interest for use in the marine environment, treatments need to be very leach-resistant otherwise they will lose their resistance with time. In European coastal waters three main wood borer species cause great destruction: Teredo navalis, Lyrodus pedicellatus and Limnoria tripunctata. Therefore before the introduction of alternative wood materials it should be ensured that they are resistant against these wood boring species. Some of the wood speCies mentioned above and also some of the wood modifications may be good alternatives for maritime construction.

Les pressions environnementales apparues en France et en Europe au cours des dernières décennies ont considérablement changé les méthodes de protection du bois. Dans ce contexte, le règlement relatif aux produits biocides et la directive relative aux produits biocides conduisent au développement de méthodes de préservation plus soucieuses de l'environnement et à l’intérêt croissant pour des alternatives non biocides comme le traitement thermique ou la modification chimique. Le traitement thermique à des températures de 180 à 220°C conduit à la modification chimique de la structure des différents constituants pariétaux du bois en lui conférant de nouvelles propriétés comme une meilleure résistance aux champignons basidiomycètes et une grande stabilité dimensionnelle. Malgré ces améliorations, la durabilité conférée au bois traité thermiquement demeure insuffisante pour des applications en classes 3 ou 4 dans lesquelles le bois est en contact avec le sol ou est en présence de termites. Par ailleurs, le bore sous forme d’acide borique ou de borax présente des propriétés fongicides et termiticides. Cependant, les produits à base de bore présentent l'inconvénient d'être très facilement lessivables les rendant inutilisables pour des applications en conditions extérieures. Les modifications chimiques réalisées suite à l'imprégnation de solutions à 10% d'anhydride maléique de polyglycérol ou de méthacrylates de polyglycérol ou de résine phénol formaldéhyde avec ou sans borax avant le traitement thermique ont apporté une amélioration des propriétés des bois modifiés thermiquement et surtout une résistance aux termites avec ou sans lessivage / Environmental pressures appeared in France and in Europe in the last decades have substantially changed the methods for wood protection. In this context the Biocidal Products Regulations and the Biocidal Products Directive lead to the development of more environmentally friendly preservation methods and the growing interest in non-biocidal alternatives such as thermal treatment or chemical modification. Wood heat treatment at temperatures of 180 to 220 °C leads to the chemical modification of wood cell wall polymers conferring new properties to the material like its increased decay resistance and high dimensional stability. Despite these improvements, the durability of wood heat treatment is not sufficient to envisage use class 3 and 4 applications; where the wood is in contact with soil or termites. Moreover, Boron compounds present fungicidal and termiticidal properties. However, boron compounds have the drawback of being very easily leached out from wood making it unusable for applications in outdoor conditions. Wood chemical modification carried by the impregnation of aqueous solutions (10 %) of maleic anhydride polyglycerol adduct or polyglycerol methacrylates or phenol-formaldehyde resin, with or without borax followed by heat treatment at 220°C has shown some improvement of thermally modified wood properties particularly its resistance to termites in case of leach or not

L’évolution des lois relatives à l’utilisation de produits biocides impose d’étudier des méthodes innovantes de traitement du bois. Dans ce contexte, les travaux de recherche présentés s’intéressent à une nouvelle alternative dite « non-biocide » impliquant la fabrication de composites bois massif / polymères obtenus par imprégnation de monomères et polymérisation in situ provoquée par chauffage. Le méthacrylate de méthyle, quatre acrylates organiques et trois acrylates hydrosolubles, ainsi que l’alcool furfurylique ont été testés. Les composites fabriqués ont été caractérisés : le polymère est bien présent dans le bois et il peut être résistant au lessivage à l’eau. Le bois a été densifié, les composites sont alors moins hydrophiles et plus stables dimensionnellement ; les propriétés mécaniques sont améliorées. Le traitement peut induire une durabilité conférée élevée. Parallèlement, une méthode d’imprégnation innovante a été testée : l’imprégnation axiale. Ce procédé consiste en l’imprégnation basse pression de billons de bois vert par une solution de traitement transitant via les voies naturelles de circulation de la sève. Des billons ont été imprégnés avec une solution de cuivre, dosé ultérieurement afin de s’assurer de la bonne répartition du produit dans le bois ; cela a permis la validation du procédé d’imprégnation axiale pour le hêtre, le charme et le bouleau. Enfin, des composites ont été fabriqués par imprégnation axiale de solutions aqueuses polymérisables à base d’alcool furfurylique ; ils sont résistants à la lixiviation à l’eau et moins hydrophiles que le bois naturel. Leur durabilité face aux champignons lignivores est améliorée, particulièrement dans le cas du traitement le plus concentré / The evolution of laws on the use of biocide products makes it necessary to explore innovative methods of treating wood. In this context, the presented research focuses on a new alternative called a "non-biocide" treatment method involving the manufacture of solid wood-polymer composites obtained by impregnation of monomers and in situ polymerization caused by heating. Methyl methacrylate, four organic acrylates and three water-soluble acrylates, and furfuryl alcohol were tested. Composites manufactured were characterized: the polymer is present in the timber and may be resistant to leaching in water. Wood has been densified, while the composites are less hydrophilic and more dimensionally stable; the mechanical properties are improved. Treatment can induce high durability. Otherwise, an innovative method of impregnation was tested: axial impregnation. This process consists in the low-pressure impregnation of green wood ridges by treatment solution transiting via natural pathways of sap circulation. Ridges were impregnated with a copper solution, later determined to ensure good distribution of the product in the timber; this allowed the validation of the axial impregnation method for beech, hornbeam and birch. Finally, the composites were produced by axial impregnation of polymerizable aqueous solutions based on furfuryl alcohol; they are resistant to water leaching and less hydrophilic than the original wood. Their durability in the presence of wood-destroying fungi is improved, particularly in the case of the more concentrated treatment