%0 Research article
%T Microfibril angle and density patterns of fertilized and irrigated Norway spruce
%A Lundgren, Christina
%D 2004
%J Silva Fennica
%V 38
%N 1
%R doi:10.14214/sf.439
%U https://silvafennica.fi/article/439
%X Two Norway spruce nutrient optimisation trials, one in the north of  Sweden and one in the south, were used to study the effects of intensive  growth and fertilization on wood density and microfibril angle. Three  different treatments and a control were available; daily irrigation,  daily liquid fertilization and solid fertilization. The nutrient  optimisation was based on foliage analysis and the solid fertilization  essentially comprised the same amount of nutrients but was applied  annually in solid form. Measurements of density and microfibril angle  (MFA) were performed using X-ray diffraction. Growth rate, expressed as a  transformation of annual ring width, was very important at the southern  site when the effect of cambial maturation had been taken into account.  Effects of both fertilization and irrigation remained strong and  significant for density, and irrigation was a significant factor  explaining MFA. At the northern site distance from pith was the dominant  factor but the effect of growth rate was also strong and the treatment  effect was significant for both density and MFA. The combination of  higher MFA and decrease in density for fertilized trees resulted in a  lower calculated strength of the wood. An over 100% increase in ring  width only corresponded to approximately a 20% decrease in wood density  and the production of wood dry matter was hence increased by treatments.