Abstract Regression of heights and diameters at age 30 over those at earlier ages were calculated for 21 uniform populations, each consisting of 31 or more slash, loblolly, longleaf, or shortleaf pines in the interior of a plantation established in one winter, at one spacing, on one soil type. The analyses showed that trees that would be of superior size at age 30 could be identified with a high degree of certainty at age 20 and in some instances at age 15, but (especially in longleaf pine) not at earlier ages. Each of the four species included trees (possibly genotypes) that reached greatly superior size by age 30, but manifested their superiority little if any before age 15. These findings suggest that measurements of progeny tests at 10 years or earlier should be accepted with reservations, particularly as guides to the roguing of seed orchards. Forest Sci. 17:200-209.
Philip C. Wakeley (Tue,) studied this question.