Differences in growth and weight of genotypes of pine with special reference to clones of Pinus radiata

The correlations between tree height, diameter at breast height (1.4 m), number of branch clusters, number of branches, and branch basal area for nine New Zealand clones of Pinus radiata D. Don. were all positive, and similar to those found for six clones in Australia. While clones could, therefore, be graded according to size, principal component analysis indicated that there was a range of "branchiness " within a given size. Current branch basal area increment per unit stem basal area increment was broadly similar for all nine New Zealand clones. Distinct, differences among clones in the relationship of total branch basal area to stem basal area indicated that past growth rates of these two parameters must have been different, while slight differences among clones, if maintained, would lead to different relative rankings in the future. Principal component analysis of component weights of genotypes of P. radiata, P. elliotti! Engelm., P. taeda L., and P. virginiana Mill, suggested that genotypes could be rated in terms of both over-all size and relative branchi-ness. For these four species there was little indication that increasing the fraction of wood plus bark growth allocated to stems increased total stem production. However, this conclusion could reflect the relatively open-grown condition of the trees