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• 1. [Article] Effect of thinning and fertilization on wood properties and intra-ring characteristics in young Douglas-fir

  The purpose of this study was to determine if thinning, fertilization or a combination of thinning and fertilization had an effect on overall average specific gravity, modulus of elasticity, modulus of ...

  Citation × Citation Citation Abstract Copy Title: Effect of thinning and fertilization on wood properties and intra-ring characteristics in young Douglas-fir Author: Bodner, Josef The purpose of this study was to determine if thinning, fertilization or a combination of thinning and fertilization had an effect on overall average specific gravity, modulus of elasticity, modulus of rupture, fiber length and intra-ring characteristics. Material for this experiment consisted of 7 trees randomly selected from each of two thinning/fertilization treatments and a control (unthinned and not fertilized) stand. Thus a total of 21 trees were involved. The trees were cut in the summer of 1982. Static bending tests were done on juvenile and mature wood from trees of all plots at the butt and at a height of 18 feet. Specific gravity and fiber length were also determined. The intra-ring parameters (earlywood width, latewood width, ring width, earlywood density, latewood density, ring density, minimum earlywood density, maximum latewood density, density range and percentage latewood) were determined by X-ray studies. Statistical analyses showed significant differences between treatments (thinning, or thinning/fertilization) in modulus of elasticity, modulus of rupture, fiber lengths and all the intra-ring parameters. Overall average specific gravity did not differ significantly among treatments but did between butt and top (18-foot height) wood values. Ring width and ring density seemed most influential on mechanical properties. Average modulus of elasticity for the samples tested were 10.6% (for the thinning/fertilization experiment) and 17.3% (for the thinning experiment) less than comparable values in the control plot. Average modulus of rupture for the samples tested were 6.3% (for the thinning/fertilization experiment) and 12.4% (for the thinning experiment) less than comparable values in the control plot. Age seemed to have the most influence on fiber length. Thinning treatments within the tree age-range of juvenile wood affected intra-ring parameters less than did such treatments in the age-range of mature wood. Fertilization by itself did not significantly increase tree growth (annual ring width). Title: Effect of thinning and fertilization on wood properties and intra-ring characteristics in young Douglas-fir Author: Bodner, Josef The purpose of this study was to determine if thinning, fertilization or a combination of thinning and fertilization had an effect on overall average specific gravity, modulus of elasticity, modulus of rupture, fiber length and intra-ring characteristics. Material for this experiment consisted of 7 trees randomly selected from each of two thinning/fertilization treatments and a control (unthinned and not fertilized) stand. Thus a total of 21 trees were involved. The trees were cut in the summer of 1982. Static bending tests were done on juvenile and mature wood from trees of all plots at the butt and at a height of 18 feet. Specific gravity and fiber length were also determined. The intra-ring parameters (earlywood width, latewood width, ring width, earlywood density, latewood density, ring density, minimum earlywood density, maximum latewood density, density range and percentage latewood) were determined by X-ray studies. Statistical analyses showed significant differences between treatments (thinning, or thinning/fertilization) in modulus of elasticity, modulus of rupture, fiber lengths and all the intra-ring parameters. Overall average specific gravity did not differ significantly among treatments but did between butt and top (18-foot height) wood values. Ring width and ring density seemed most influential on mechanical properties. Average modulus of elasticity for the samples tested were 10.6% (for the thinning/fertilization experiment) and 17.3% (for the thinning experiment) less than comparable values in the control plot. Average modulus of rupture for the samples tested were 6.3% (for the thinning/fertilization experiment) and 12.4% (for the thinning experiment) less than comparable values in the control plot. Age seemed to have the most influence on fiber length. Thinning treatments within the tree age-range of juvenile wood affected intra-ring parameters less than did such treatments in the age-range of mature wood. Fertilization by itself did not significantly increase tree growth (annual ring width). Close