The study identified for stand managers the margin at which faster growth rate of boreal white spruce on good sites in northeastern British Columbia becomes detrimental to commercially important wood attributes. One hundred and eight white spruce (Picea glauca (Moench.) Voss)) trees were selected in equal numbers in 30 cm, 40 cm and 50 cm tree diameter-at-breast height (d.b.h.) classes from each of three natural stands with mean ages of 119, 109 and 99 years. Disks were cut from stump, breast height and at 20 percent stem height intervals to determine radial and vertical trends in basic relative density, heartwood/sapwood proportions and moisture content, and incidence and severity of spiral grain, longitudinal shrinkage, and compression wood. Mechanical properties were determined from clear wood specimens obtained from bolts cut at breast height and 40 percent tree height. Wood density, bending MOE and MOR, MOE in compression and UCS, all declined significantly as tree d.b.h. class increased from 30 cm to 50 cm. Spiral grain angle was unrelated to growth rate, but the typical offsetting radial trend of left-to-right hand spiral was not fully developed. Longitudinal shrinkage was greatest near the pith and increased with tree d.b.h. class in two of the three samples. Percent compression wood content was low and unrelated to growth rate. Heartwood proportion was significantly lower in the lowest age sample. Branch size increased with increased d.b.h. class. A wood quality discount will apply to white spruce grown at a rate corresponding to 50 cm d.b.h. in 100 years.