VOLUME 49, ISSUE 4/2008

Round wood supply and round wood demand in Germany proved to be increasing significantly during the last 15 years. Contingent on assumptions regarding the forest management behaviour, no to only small unutilized round wood potential can be expected for the future. At present, there is already no unutilized coniferous round wood potential in many regions. Additional claims to the forests regarding maintenance and improvement of biodiversity and climate protection indicate supply shortages in the future. In order to avoid them a variety of measures can be identified. In any case, intensification of forestry will be a core measure among them.

Wood consumption is dramatically increasing. On the one hand this is due to the increased demand of the construction and furniture industries, but in particular to the consumption of wood for energy generation in biomass energy plants or private households, which is a politically declared aim and subsidized by the governments. This development is furthermore enhanced by the proposals of the EU-Commission with regard to the encouragement of the use of renewable energy sources. Consequently, there is a shortage of the raw material wood. The German Wood-based Panel Association (Verband der Deutschen Holzwerkstoffindustrie e. V., VHI), therefore demands, that the subsidies for burning high-value wood should be stopped and a change of objectives should take place. According to the principle of cascading utilization, wood should be used several times in substance in a sustainable manner before it is used for energy generation. This contributes more to the protection of the climate than direct incineration of wood.

Wrapping logs in an airtight manner in a plastic wrap is an alternative way to protect logs that is cheaper and more environment friendly than the traditional methods. In a hermetically sealed pile, an oxygen-deprived atmosphere that thwarts the growth of wood decaying fungi, develops in a short time. The goals of the laboratory and industrial scale experiments described in this article were the assessment of the application of this method for Hungarian species and circumstances, assessing the effect of adding dry ice to the piles and creating an optimal storage technique. Since wood protection is achieved primarily through an oxygen deprived environment, rather than the presence of carbon-dioxide, adding dry ice is unnecessary. The quality of lumber and veneer originating from logs stored successfully in this manner was equivalent to those made of traditionally stored materials.

Bending strength, MOE, shearing modulus, compression strength and Brinell hardness were tested. MOE increases almost twice as much as not compressed wood. Bending strength increases about 50 – 60 %. Brinell hardness increases about 300 % and compression strength increases about 400 % in tangential direction and 500 % in radial direction.

Wood Plastic Composites (WPC) and particle board were plasma treated by a dielectric barrier discharge at atmospheric pressure. Thereby surface energy increases and wetting improves. Plasma treatment of WPC entails an increase in adhesion of lacquers and can resolve adhesion problems. On particle boards, enhanced wetting results in accelerated water penetration und can reduce drying times of water solvent adhesives.

Investigations of thermo-smoothing of inner profiles and edges of furniture fronts have clearly demonstrated the beneficial effects of thermo-smoothing. It is possible to achieve a very considerably surface-quality with smoothing than with milling. The danger of cracks of edges is lower with thermosmoothed surfaces. A two layer coating is much more safe with regard to cracks, but it is also more expensive. However, the investigations show the partly insufficient process stability of powder coating, in view of the powder application, the temperature in the oven and the characteristics of MDF. Alternating characteristics of MDF, particularly conductivity and density, require a permanent readjustment of the coating process. This may affect the process stability and efficiency.

Today’s variety of products would not be possible without modern adhesive technology. Regarding to the DIN EN 923 an adhesives is a bonding agent, which keep parts together by adhesion and cohesion. Mankind discovered adhesives thousands of years ago by observing their broad use in nature, and for most of these years adhesives were made from natural, renewable materials. Synthetic raw materials became popular in the twentieth century but now, as the price of crude oil increases dramatically, there is a movement back to natural and renewable raw materials. The discussion on reduction of carbon dioxide emissions also drives this movement to look again at materials like tree resins, starch, casein, or gelatine.

The present article describes an application of computed tomography (CT) to generate 3D volume models of softwood. A medical scanner was used to obtain CT data of pine specimen. To get accurate 3D models a segmentation to separate late- and early-wood was performed. The 3D volume models may in future be applied to perform a Finite Element Analysis (FEA) or general computer simulations. The method allows also to model further anatomical features of wood like knots or resin pockets.

The buildings on the caste hill in Meißen are among the most famous edifices of Saxony's cultural and settlement history (Fig. 1). Especially the cathedral and the first German palace building – the Albrechtsburg – are closely linked with the 1000-year history of Saxony. Since the first establishments by king Heinrich I. in the year 929 the castle hill had been the mundane and intellectual centre of the March Meißen. Under the auspices of the master builder Arnold von Westfalen the Albrechtsburg-Castle was built in the late Gothic style in the 15th century. The changeful history of this building has seen both destructions due to major fires (1773) and wars, and profound constructional modifications for the commercial usage of the chinaware factory and museum [1, 2]. The allocation of the various parts of the building and the different sections of the roof thus to the individual constructional phases should be analysed on the basis of wood-anatomical and dendrochronological investigations.

In a diploma work wood fibre mats were manufactured and tested on their strength and transforming properties. Thermoplastic bi-component fibres and thermosetting bonding agents (phenol formaldehyde resins Resol and Novolak and acrylate Acrodur.) were used. The connection of the wood fibre mats was realized by melting of bi-component fibres through hot-air. Afterwards these wood fibre semi-finish materials, which also bonding with thermosetting glues, were processed into boards or moulded part in a hot-press. The investigations showed that it is possible to manufacture transformable wood fibre mats, and that their final products showed good strength properties.

The intensified requirements of products concerning the formaldehyde release require a more effective self-monitoring of the materials in the enterprises themselves. This is possible by the application of an online measuring instrument, which was developed and tested with the company Medizinand Labortechnik Engineering (MLE). Correlation investigations of laboratory particle boards showed an assured coherence between the measured emission values according to the test chamber method and the online measuring method. For supervision in the production process selected parameters of the testing method are to be modified due to the product specific emission behaviour. This online measuring instrument can make a substantial contribution for the asurance of the product quality.