Climate, location, and growth relationships with wood stiffness at the site, tree, and ring levels in white spruce ( Picea glauca) in the Boreal Plains ecozone1.

We examined modulus of elasticity (MoE) derived from SilviScan in white spruce ( Picea glauca (Moench) Voss) at the site, tree, and ring levels across the Boreal Plains ecozone in Canada. Area-weighted averages of MoE were calculated for juvenile and mature wood and were examined in relation to radial growth, climate, and location. Correlations indicated that there was a negative relationship between radial growth and MoE in the juvenile wood that was detectable at the site and tree levels; however, the relationship weakened in the mature wood, particularly at the site level. Few climate variables were correlated with MoE in juvenile wood, whereas multiple summer and fall climate variables showed a significant correlation with MOE in mature wood. A model describing the radial profile of MoE explained 58% of the variability in MoE, with 10% of the random variability attributed to between-tree differences. Elevation and summer water balance accounted for nearly all of the between-site variability. A decrease in MoE with increasing elevation was noted and has been previously linked to a decrease in cell wall thickness due to a shorter growing season at higher elevations. Integration of the MoE profile model into an individual-tree growth and yield simulator is the next logical step. [ABSTRACT FROM AUTHOR]