Climate warming has been an unquestioned phenomenon within the last 50 years and it may be explained first of all by anthropogenic factors (increasing emissions of greenhouse gases and a reduced capacity of carbon sequestration as a result of deforestation). Further warming is inevitable and its extent depends on the adopted pathway of socio-economic development and the policy to prevent climate warming. If global emissions of greenhouse gases are going to increase further in an uncontrolled manner, warming may take a dangerous dimension. Thus it is a primary aim to reduce the intensification of the greenhouse effect using all possible means – thanks to reduced emissions and/or increased capture of carbon dioxide. Manufacture of wood products and in this category also ecological wood protection need to be focused on. Use of wood instead of concrete, steel or plastic in the construction industry saves energy and thus reduces emission of CO2 in the production process. Extension of life for wood products due to appropriate wood protection will facilitate a longer period of carbon capture in wood, i.e. an increase in the pool of bound carbon and a reduction of CO2 emission. This will limit the greenhouse effect and as a consequence stop the acceleration of climate change. The better protected (preserved) wood is, the longer the period carbon is captured in the wood. Moreover, implementation of novel solutions and wood protection technologies planned within this project will make it possible to use low quality wood material to manufacture high quality products (e.g. construction or cladding materials). For this purpose optimisation of wood harvesting and manufacture of wood products is needed, taking into consideration the greenhouse gas balance. In this manner such eco-friendly wood protection will be a key factor reinforcing climate protection.

Wood as a natural polymer and an organic and renewable raw material due to its specific properties (e.g. high strength, elasticity, unparalleled esthetic value), is applied in many sectors of the society. However, the basic problem crucial from the economic point of view, observed during the use of wood in numerous types of applications particularly in broadly understood construction industry, is its susceptibility to the destructive action of abiotic and biotic factors. Wood degradation under the influence of abiotic factors is a major cause for both the limitation of applicability and reduction of lifespan for wood products. Variable weather conditions lead to a deterioration of the dimensional stability of wood. It results in cracks on its surfaceand promotes development of wood degrading organisms. Increased wood resistance towards the above mentioned factors is obtained using specific treatment methods (surface or immersion), fungicides, insecticides, algaecides, and occasionally even bactericides. Solutions applied to date in wood protection to a considerable degree are based on conventional preparations containing active substances which, exhibiting high efficacy and toxicity. Thus they constitute a hazard to human health and natural environment. Stricter toxicological requirements and an increasing ecological awareness of consumers have contributed to decisions to cease production of harmful agents. This is connected mainly with the introduction of directives concerning e.g. VOC (DIRECTIVE 2004/42/EC) and biologically active substances (DIRECTIVE 1998/8/EC). The implementation of limits for VOC contents in products forced producers to adapt existing products to requirements as well as implement new technologies . In view of the undertaken research, an equally important aspect is economics, concerning the development of technologies guaranteeing potentially low production costs. It is also essential that in view of high registration costs of biocidal products, compounds which are not active substances are gaining in importance.

Most wood defects result from its hydrophilic character, thus organosilicone compounds comprise an important group not only due to their low toxicity, but also exceptional hydrophobic properties. Effectiveness of organosilicone compounds is varied, since it depends on many factors, e.g. the applied treatment method, type and amount of silane as well as the presence of other adjuvants like alkaloid, imidazoles, natural oils or propolis. Chemical wood modification with silanes results in a change of hygroscopic properties of wood, thus reducing negative effects of exposure to water and steam, and as a consequence it protects against fungal development . Since silanes in the course of surface treatment form a very thin layer on wood surface, they exhibit low water resistance. The autors of the project propose the application of a composition of silanes with resin. In this way coat thickness is increased to 10 – 30 μm. This solution is considered advantageous also for economic reasons. Effective wood protection with silane alone is obtained at its high concentrations (over 20%). At the same time it is suggested that silane as a component of the protection treatment system may be applied at 5%. Silanes may regulate such properties of products, coats and coatings as wettability of pigments, preventing their floating, and flow, gloss, resistance to water and atmospheric factors as well as mechanical factors, particularly abrasibility. In view of the above mentioned arguments it was decided to undertake research aiming at the assessment of properties of biocide-free wood protection treatment systems modified with selected organosilicone compounds, alkaloids, imidazoles, natural oils and propolis.

The objective of the project is to investigate experimentally, under laboratory conditions, the effect of non-biocidal, eco-friendly novel substances introduced into model protection treatment systems on the modification of selected properties of wood for outdoor and indoor applications. The analyses will be conducted on systems, to which in place of conventional biocidal substances, it will be proposed to apply alternative compounds from the group of silanes, alkaloids, imidazoles, natural oils and propolis or their mixtures. The scientific essence of the work consists of a research problem connected with the effect of hydrophobicity of wood surface on its resistance against abiotic factors and wood surface bioactivity against biotic destructive agents.

The primary aim of the research is to determine fungicidal properties of biocide-free systems with a varied quantitative share of the above mentioned groups of chemicals. Moreover, surface phenomena will be evaluated for the developed systems in relation to the assumed criteria of the adsorption theory of polymer adhesion to wood. Due to the strongly stressed practical aspect another objective is to propose solutions for industrial practice. Furthermore, the scope of the investigations comprised evaluation of physico-chemical properties of the systems, determination of their wood penetration capacity, determination of absorbability in water, characteristics of protected surfaces, resistance to aging factors, including water and UV radiation as well as assessment of resistance to biotic factors. Thus it is essential to promote wood production, which from the point of view of the carbon cycle in nature means a temporary exclusion of a certain pool of carbon from the cycle until the time when wood products will no longer be used and will be degraded (e.g. at waste disposal dumps) or incinerated. In both cases carbon dioxide will be released to the atmosphere as a greenhouse gas enhancing global warming. The idea is for the carbon pool bound in the wood production complex to be possibly the highest and to increase constantly, which may be achieved by maximisation of the carbon flux entering the wood production complex and by minimisation of the carbon flux released from this complex. Wood protection has a significant effect on the latter flux.

It is justified to use wood to replace other materials e.g. construction materials, which production requires the consumption of greater amounts of energy (metals, concrete, plastics). The origin of energy is also essential – from renewable sources (e.g. biomass) vs. combustion of fossil fuels. Mitigation of climate change requires increased amounts of carbon in wood products, their extended life (a longer period of carbon binding and less energy required for the replacement of old products with new ones) and an increased degree of the carbon cycle closure (recycling). Wood products should be cheap, safe and durable, while their stability should depend first of all on modern eco-friendly wood protection. We also need to consider potential for optimisation of recycling and the effect on processes of waste storage (in order to reduce the process of wood decomposition and the rate of carbon dioxide release to the atmosphere), development of the market for wood and its products as well as extension of life for wood products (SLP). The possible more extensive use of impregnated wood from local species of low resistance in order to replace wood from species of high natural resistance, originating mainly from tropical forests, would decrease deforestation of tropical forests, while on the other hand it would prove advantageous for climate protection thanks to carbon binding by vegetation. Moreover, it would be possible to considerably reduce high CO2 emissions to the
atmosphere connected with transport of wood of tropical species over large distances.