Existing European standards for finger-jointing of load-bearing lumber require the wood to be dried before gluing. This article presents a study on the properties of green-glued finger joints, wet wood being bonded prior to drying. Issues to consider, in comparison to finger-jointing of dry wood, are mechanical performance of the joint, absorption of the polymer by the wood in its natural/wet state, and the chemical reactions of the adhesive on contact with water. Finger-jointed samples were tested in bending, and the glue joints analysed by optical microscopy, scanning electron microscopy and microdensitometry. A patented one-component polyurethane adhesive developed for gluing-green wood which has a moisture content usually higher than 70% was used in the study. The resulting green-glued joints showed improved strength properties in comparison to dry-jointed joints. The results confirm that green-glued joints provide a wide, continuous wood/adhesive interface from one substrate to the other. The adhesive penetrates several cells deep and the density of the wood adjacent to the joint surfaces is increased. The results also indicate that the patented adhesive forms covalent bonds to the wood substrate.
1 July 2019 in Resources, Conservation and Recycling
The Landes de Gascogne forest, located in southwestern France, spans nearly 10,000 km2 and consists largely of maritime pine (Pinus pinaster). This forest in unique to Europe because it is almost entirely created and managed by man for specific industries. On the basis of a material flow analysis, we assessed the upstream supply chain of maritime pine from 2013 to 2019, using a cradle-to-gate approach. The assessment is based on data provided by Alliance Forêts Bois, an important stakeholder of the region and leader in the production of forest resources in France. For various reasons, the harvest totals decreased 10% in the last years. We identified a clear orientation to specific industries—in 2019, 45% was used as pulpwood. This is due to the overall design of the current territory, species of tree, and market values of the pulp and paper industry. The current design provides a limited supply of old growth trees, which produce high-quality logs for construction-based products, and are also more resistant to climate variability. A future shift or balance in raw material flows could be a crucial step in protecting the long-term economic viability of the region. This article aims to contribute to new attempts in providing comprehensive views of stocks and flows in the French forest-wood supply chain.
10 May 2018 in Southern Forests: a Journal of Forest Science
An alternative approach to the formal management strategy of tropical timber species from the Congo Basin was investigated. It focused on the development of glulam, with an aim to specify a decision support model for the valorisation of tropical timber species considered for use in these products. There were 76 forest species analysed regarding ecological, engineering and social criteria according to their major uses. The Electre TRI-B multicriteria sorting method was used. The main result was a new and robust classification tool of timber species from the Congo Basin, corresponding to their multicriteria consensus degree. The potentials of the new grouping system were analysed. Species that meet a great majority of criteria were identified. They were highly suitable for sustaining the market position of glulam products. Implementing this strategy may significantly improve the management and increase the value of the timber species from the Congo Basin, while preserving endangered species.