GROWTH: Growth potential and wood properties of selected tree species of various provenances: modification options, prospects and challenges in response to climate change

Climate change is fundamentally affecting forests. These rapid changes require tree species to adapt or migrate more quickly than was the case in the past. Tree species or provenances that are more resilient to drought or wind damage may have a better chance of surviving under such unpredictable circumstances. The radial growth potential and wood properties of selected tree species and provenances are investigated at different sites in Slovenia: Pinus nigra and Fagus sylvatica. In detail, the following objectives are pursued: (i) By using a dendroclimatological approach and quantitative wood anatomy, the climate-growth relationship in the selected species and provenances and their adaptability to changing environmental conditions will be investigated. By examining densitometric profiles, we will establish a link between climate growth potential and wood properties and thus assess the most likely future wood properties as a result of global warming. (ii) By testing key wood properties, we will compare the wood quality of the selected species and provenances to assess the potential for different applications. (iii) Genetic approaches will be used to gain insights into the genetic control of growth and wood properties and to disentangle the historical relationships between provenances to help select the best forest reproductive material. The proposed research topic is complex as it combines the latest knowledge from different research groups in forestry, wood science and technology, and the construction industry in the areas of forest genetics, tree biology, wood structure, mechanical properties and durability. Wood is a material made from renewable raw materials with excellent properties. The main disadvantages of wood are its flammability and its tendency to decompose. To improve these weaknesses, wood can be modified using various techniques. However, each of the existing methods still has various disadvantages. Moreover, there is a lack of efficient, non-biocidal protection of wood against biological decay that does not affect the relevant properties of wood and at the same time increases fire protection. The main objective of this project is to identify the optimal method for non-biocidal protection of target wood species against decay - without significantly changing the relevant properties. At the same time, we will look for solutions to increase the fire performance of wood within the same process. One of the proposed approaches is to look for synergy effects by combining individual techniques for the same material. We will introduce an innovative idea of mineralisation by impregnating the wood with soluble carbonate-based compounds that penetrate deep into the wood structure and combine it with various known approaches, such as thermal modification. We expect that in this way, the protective effect and durability of wood can be maximised and its disadvantages minimised. We will systematically investigate the synergistic effect of different methods of wood modification. In recent decades, the most important development in the European timber construction sector has been the development of solid wood constructions made of glulam products such as glulam (GLT) and cross-laminated timber (CLT). These products can be used in constructions that were traditionally reserved for mineral building materials. Concepts for improving product performance and properties through the use of laminates made from hardwood species are being investigated. The use of hardwood species is motivated by a) climate change and changing growth conditions, b) favourable mechanical properties in terms of material strength and stiffness. Laminations of selected hardwood species (e.g. beech) can be combined with laminations of softwood species (pine), recycled wood and wood-based materials to form high-performance structural elements.