White Oak Growth after 23 Years in a Three-Site Provenance/Progeny Trial on a Latitudinal Gradient in Indiana

To increase the availability of improved, adapted white oak (Quercus alba L.) for midwestern United States landowners, we analyzed data from three 23-year-old provenance/progeny tests of 70 open-pollinated progenies from 17 provenances. Our goal was to estimate the heritability of height growth and range of adaptation and ultimately to determine the value of converting the sites to seed orchards. Tree growth was marked by positive spatial autocorrelation (SA) for height in all three test sites despite differences in management and mortality. Microsites with the highest SA changed little from age 10 to age 23. Nearest neighbor and iterative spatial or kriging analyses were used to remove effects of SA from the data, resulting in little change in heritability estimates but important changes in family means and rank. Within sites, provenances were a relatively unimportant source of variation (mostly 2%), and there was no evidence local sources grew best. Genetic correlation was 0.81 for height between ages 10 and 23. Considering heritability estimates, significant differences among families, and large predicted breeding zones, once the sites are thinned, seedlings produced from the progeny tests should grow well above average on suitable sites in Indiana and would probably be acceptable in nearby states as well.