As wood products in use store carbon and can contribute to reducing the concentration of atmospheric CO2, the improved and enhanced use of wood products can be a successful measure in climate change mitigation. This study estimates the amount of carbon stored in the Hungarian harvested wood product (HWP) pool and the CO2 emissions and removals of the pool. According to our results, the total carbon stock of the Hungarian HWP pool is continuously increasing. We estimated the total carbon stock of the HWP pool to be 17,306 kt C in the year 2020. Our results show that the HWP pool in Hungary is a carbon sink in most parts of the time series, with some years where it turns to a source of emissions. We carried out a simple projection up to 2070, assuming a constant inflow for the projected years that is equal to the average inflow of the last five historic years. This resulted in a decreasing trend in CO2 removals, with removals already very close to zero in 2070. We concluded that in order to achieve significant future carbon sinks in the HWP pool technological improvements are needed, such as increasing the lifetime of the wood products and expanding the carbon storage capacity of wood products by reusing and recycling wood in a cascade system.

Harvested wood products (HWPs) store a significant amount of carbon, and their lifetime extension and appropriate waste management, recycling, and reuse can contribute remarkably to the achievement of climate goals. In this study, we examined the carbon storage and CO2 and CH4 emissions under different scenarios of 200,000 m3 particleboard manufactured in 2020 by a hypothetical manufacturer. The scope of our investigation was to model the effects of a changing product lifetime, recycling rates and waste management practices on the duration of the carbon storage in wood panels and on their emission patterns. The aim of the investigation was to identify the most climate-friendly practices and find the combination of measures related to HWP production and waste management with the highest climate mitigation effect. We used the newly developed HWP-RIAL (recycling, incineration and landfill) model for the projections, which is a combination of two IPCC models parametrized for Hungarian circumstances and supplemented with a self-developed recycling and waste-route-selection submodule. The model runs covered the period 2020–2130. According to the results, the combined scenario with bundled mitigation activities had the largest mitigation potential in the modelled period, resulting in 32% emission reduction by 2050 as compared to the business-as-usual scenario. Amongst individual mitigation activities, increased recycling rates had the largest mitigation effect. The lifetime extension of particleboard can be a complementary measure to support climate mitigation efforts, along with the concept of cascade use and that of circular bioeconomy. Results showed that landfilled wood waste is a significant source of CH4 emissions on the long term; thus, incineration of wood waste is preferable to landfilling.

<p class="p1">A gyakorlatban sokszor előfordul egyes mezőgazdasági vagy faipari anyagok pelletálása, amelynél a nyomás eléri vagy meghaladja az 1000 bar értéket.<span class="s1"> A tömörítés folyamán a </span>sűrűség<span class="s1"> és vele a rugalmassági modulus is </span>gyorsan növekszik. A fa illetve a belőle készített pellet viszkoelasztikusan viselkedik, tehát a nyomás-deformáció összefüggés az időtől illetve a <span class="s1">terhelés seb</span>ességétől is függ. <span class="s1">A por-forgács halmazok tömörödésével</span> összefüggő korábbi <span class="s1">kutatások azt mutatták, hogy még egészen kis összenyomásnál sem rendelkezik a tömör faanyag a Hooke-féle rugalmassági tulajdonságokkal (Sitkei 1981). A terhelés-teherintenzitási ciklus végén mindig visszamarad egy</span> bizonyos értékű deformáció. A deformáció nagy része a tehermentesítés során nem nyerhető vissza. A feszültség-deformáció viszony az idő mellett a<span class="s1"> feszültség nagyságától is függ, tehát nem-lineáris viszkoelaszticitásról beszélhetünk (Sitkei 1994). A jelenleg is </span>folyamatban lévő kutatások során <span class="s1">– ahol a pelletálási folyamatra je</span>llemző nyomófejet is készítettünk<span class="s1"> – olyan komplex nem-lineáris rheológiai modell kifejlesztését</span> tűztük ki célul, amely az anyag rugalmas, viszkoelasztikus és plasztikus tulajdonságait<span class="s1"> írja le, különös tekintettel a faalapú por-forgács halmazok préselésére széles nyomástartományokban.</span></p>

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woodscience.hu peer-reviewed article KOCSIS, CSANÁDY (2014) The most important factors are wood species, particle size, moisture content, pressure, the rate of compression, the holding time on deformation, the diameter of the ram and the temperature of pressing. The analysis of the resulting mechanical changes during high pressure compression of wood chips in possible using non-linear rheological methods, because wood has non-linear viscoelastic properties. Consequently, during the compression process the elastic modulus of wood chips and dust increases greatly, and the resulting pellet at the end of the process suffers residual deformation. The rates of residual deformation determine the properties of the pellet, especially its density. In the present stage of our research, an approximate model was developed for the description of the force and the required length of press. The derived theoretical correlations have been verified throungh experimental results. The obtained results are useful for practical applications and contribute greatly to expanding the theoretical knowledge of wood chips and dust behavior.