Patterns of basic density variation for Pinus radiata grown in south-west slopes region of New South Wales, Australia

Patterns of change from pith to bark and the distribution of variability in density across forest areas, sites, and trees were determined using data from breast-height cores taken from harvest-age Pinus radiata D. Don (ages 28 to 37 years) as part of a resource survey of four forest areas in the south-west slopes area of New South Wales. Seventeen of the sample sites had been thinned, one site was a thinning trial, and the other two sites were unthinned but matched to two of the thinned sites to determine the effects of thinning. Pith to bark cores were cut into five-ring segments and extracted basic density was determined for each segment. Little difference in average basic density was found between the forest areas, particularly for the first 10 rings adjacent to the pith. The major source of variability was between trees within each site — this accounted for 77–92% of the total variation at each age. Thinning had no discernible significant effect on density at any age. Density in the outermost five-ring segment (corresponding to ages 23–28 to 32–37 years) was poorly predicted by juvenile core density (inner 10 rings), indicating little opportunity for forward or backward prediction of density.