Study On Wood Property And Growth Performance Variation Of Alnus Formosana Clones

Alnus formosana is listed as an excellent species of pulpwood, because of its high adaptability, the great amount of tree's timber, and the potential to develop as pulp raw material. The introduction of Alnus formosana has a30-year history In China, however the pace of forestation by clone is still slow, as well as the selective breeding of superior clones.Combining the observed data of growth traits over the years, this paper measured215-year-old clones and1compared group of Alnus formosana, including fiber length, fiber width, length width ratio, basic density, Cellulose content. The difference and radial variation of9years5clones wood properties were systematically studied. Results showed:1. There were highly significant differences among clones in the growth of diameter at breast height and stem volume. The clone repeatability of growth traits was relatively large, among which the clone repeatability of diameter at breast height and stem volume reached0.533and0.5381respectively. The growth stability of clones was good. The correlation coefficients are respectively0.841(between the tree height and the volume),0.877(between the DBH and the volume),0.497(between the tree height and the DBH).2. The difference of fiber length of21clones and the compared group is significant, the maximum and the minimum are1.0763mm and1.2967mm respectively. They reach the medium-sized length standard. The frequency distributions of fiber length and width accord with the demands for paper-making raw materials.3. Wood basic density of tested clones change between0.4102g. cm-3-0.4747g. cm-3, which is suitable for paper-making raw materials, cellulose content increased gradually from pith to bark.4. The minimum of cellulose content is45.45%, which can meet the demand of paper-making raw materials.5. Basic density has significant positive correlation with DBH and volume, which indicates wood basic density can improve by fostering the large DBH wood.6.Growth traits and wood properties of21clones were evaluated. Considered wood yield and paper-making suitability,2,7,12and21should be selected. The4clones which superior to the compared group are worth popularizing in the industrial materials. The average genetic gains of stem volume was2.31%respectively. The results from this study would provide some bases for oriented culture of Alnus formosana plantation in the future.