Einfluß der Eigenschaften des Holzes einiger Pappelklone auf seine Verwertung
The results show that fibre length increases with age; the fibre length of a 5 year old poplar is comparable to that of a 50 year old beech. The wood from a 10 year old poplar is suitable for the production of pulp. The properties of poplar wood for producing paper pulps are superior to those of beech. An increase in the tension wood in poplar adversely affects the strength of the pulp, especially folding resistance. Heartwood reduces the whiteness of pulp when the NSSC-pulping process is used, but not in the sulphate process. Poplar clones grown on mineral rich sites produce high quality pulp compared to those grown on poor sites. Pulp quality from different clones is significantly different due to variations in tension wood and heartwood content, and the fibre length. There is no clear correlation between tree age and the mechanical properties of particleboard made from the wood. Particleboard processed from different poplar clones using different organic binders had slightly differe nt mechanical properties. Particleboard produced from heartwood display lower mechanical strength than particleboard produced from sapwood. Poplar wood may be used in the production of medium density fibreboards (MDF). At a density of 700 kg/cm3 , MDF from poplar are similar in their mechanical properties to those made from beech at a density of 800 kg/cm3.