Survival and initial growth attributes of improved and unimproved cherrybark oak in South Arkansas
This article is part of a larger document. View the larger document here.Abstract
Thousands of acres are planted every year with genetically improved seedlings; but while pine continues to be extensively explored, the same is not true for hardwoods due to costs and rotation length. An improved cherrybark oak (Quercus pagodaRaf.) seed orchard exists in North Little Rock, AR, providing an opportunity to evaluate hardwood improvement. However, the cost and limited testing of these seedlings have been large limiting factors in their deployment. In February 2012, improved and woods-run seedlings were hand-planted at two sites in southern Arkansas including a site near Hope, AR, and one near Monticello, AR. The sites were treated with 2 ounces per acre of Oust XP® 2 weeks after tree planting with manual control of sumac (Rhus spp.) and sweetgum (Liquidambar styraciflua L.) shortly thereafter. A random sample of seedlings at the nursery confirmed that seedling undercutting effectively controlled root length which was statistically the same for both groups at 21.8 inches. However, root collar diameter of an improved seedling was on average 27 percent larger than an unimproved seedling. These trends were similar to those among planted seedlings in which improved seedlings were 9 percent and 8 percent greater in regards to ground line diameter and height, respectively. However, improved seedlings exhibited greater initial mortality, by 6.2 percent, in the first few months of their growing season. While initial mortality is often considered random, disparity between the two groups points to other causes, such as the larger root sizes, which may pose planting problems. In conclusion, these results indicate that genetic improvement has increased 1-0 seedling size, but survivability must be carefully monitored.