Short rotation coppices (SRC) can produce large amount of dendromass in a short time. From an energetic point of view, one of the most important challenges are the outstanding amount of ash content, which is primarily generated due to the high bark content of the thin shoots. Our research was carried out for measuring bark content of four species/clones performed in three different vegetation years. The experimental plantation is located in the northwestern part of Hungary. The results show that the bark content strongly depends on the applied harvest frequency and tree species. Based on the measurements, the Robinia pseudoacacia and the Salix alba species have the largest bark content in the first year but the value can be reduced by around 50% by using longer harvest rotation. Having analyzed the whole stem, the bark percentage of the Populus x euramericana clones increased from 5.5% to 33.7% from the cutting height to the tip. The minimum value was at the diameter class of 24-28 mm. In the case of Robinia pseudoacacia the bark content ranges only between 3.0% and 20.0%.

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Due to a European Union engagement, we have to increase the proportion of renewable energies in Hungary. The percent of renewable energies should be 14,7% up to 2020. There are huge possibilities in the biomass utilization, indeed in our country herbaceous and woody plants, forestry and agricultural byproducts are available in large quantities. Because of the small bulk density of primary materials, we want to facilitate the transport and the utilization therefore the energetical compressed are received more attention. There are two new branches of energy industry were developed, the pellet and the brikett production. Our searching was performed with pelleting different types of lignocelluloses. At first the energy substance of primary materials was examined in a laboratory, after the factory inspections were performed. In our study both of fuels and manufacturing process were researched. At the end of the searching of energy balance of pellet and brikett, the two energetical results were compared. Moreover, the energetic multiple related to the product and the energetic efficiency was also calculated. We can conclude that producing of pellet and brikett with the simplest technology (without drying and long-distance transport) we can make high quality materials with a good energetical efficiency.

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