Visual Grading and Quality of 1-O Northern Red Oak Seedlings

Past resebrch has used detailed measureme$s of various growth characteristics to determine seedling grades and quality of northern red oak nursery stock This study evaluates the effectiveness ofa visual grading process. similar + thosefound in commercial nursery operations, to distinguish high quality seedlings. Northern red oak (QuercJs rubra L.) seedlings were grown for I yr at two state nurseries and visually separated into three grades (cull, @od, or premium) according to root and shoot characteristics. Approximately 64% of the seedlings grown at edch nursery were judged to be of unacceptable size for successfil~eld regeneration. Number of first-order teral roots (F0L.R). height, and tvot collar diameter (RCD) were measured for seedlings in the good a4premium grades. Premium grade seedlings were significantly larger than the good grade seedlings for both burseries. Phenotypic correlations of growth traits were strongest between number of FOLR and RCD. The qesults demonstrate that high quality nursery stock can be visually selected into two distinguishable grades. $outh 3. Appl. For. 21(2):93-97. : Mm y eastern N&American spnds currently dominated by oak (Quercus spp.) contain h&h proportions of nonoak species following natural mort& or harvesting (Lorimer 1993). This is particularly true ob high quality mesic sites (site index 2 21.3 m+), where cpmpetition is intense (cf. Johnson 1993, Trimble 1973). Ei;+n with overstoty removal, the smaller, sl6w-growing oak re witcmore vigor& species such eneration cannot compete t red maple (Acer rubrum . L) or yellow-poplar (Liriodendrc/n tulipifera L.) (Beck and Hooper 1986, L&is 1983. Sandek 1972). Historically, frequent natural and Native Americftn-set fires created conditionsfavonble for regeneration1 of oak species (Abrams 1992, Buckner and Tunill 1999). Fdditional disturbances by : settlers and the disappearance df the iAmerican chestnut (Castanea dentata [Marsh.] Bot$) maintained a significant oak component throughout much bf eastern North American upland forests (Abrams 1992, Lo+mer 1985). Fire reduction and suppression during,this centup has aIlowed other species that are less fire-resistant to achieve dominance in stands which previously contained a high proportion of oak species (Watt et al. 1992). . No&c &E. hhlarbaum is the cotrespond i ng author, and he can be rcachcd at (423) 974-71263 Fax: (423) 974473 ; E-Mail: [email protected]. The authors wish to thank the following: , r. J. Branan from the Georgia Forestry Commission and Mr. S. Hawk om the North Carolina Division of Forest Resources for their assistance’ in furnishing seedlings for this study; Profcs&X A. Saxton from the Uni+ crsity of Tennessee’s Statistical and Computing services for assistance *ith statistical analysis: and the c USDA Forest SerViCC for Phalsupporr fthis study. Manuscript rcceivcd March lg. 1999. accepted kobcr 8, I 9i9 . Artificial regeneration of different oak spe&es has been attempted to supplement natural regeneration on high quality sites. Generally these anempts have had limited success. as the oak seedlings were overtopped by faster growing vegetation. The resulting deciease in light caused suppression and senescence (Johnson 1976, McGee and Loftis 1986, Russell 1973). Planting failures can be partially attributed to the failure of commercial fast tree nurseries to produce and grade seedlings to provide high quality nursery stock. Nurseries typically establish their own procedures for growing oak seedlings (Kormanik and Ruehle 1987). directed toward attaining a uniform size to facilitate handling, shipping, and planting procedures (Johnson 1981, Kormanik and Ruehle 1987). and grading of hardwood seedlings is not a common nursery practice. Previous studies have been conducted to determine relationships between seedling size at planting and subsequent growth in the field. Northern red oak CQ. rubrai.> / seedlings with taller stems at planting have been shown to have better height growth over time than smaller nursery seedlings (Foster and Farmer 1970. Johnson 1976, Zaczek et al. 1997). Nursery seedlings with the highest numbers of first-order lateral roots (FOLR) generally were tallest after one growing season in the nursery (Kormanik et al. 1994a, Ruehle and Kormanik 1986) and after 3 to 7 yr in the field (Kormanik et al. 1995, Teclaw and Isebrands 1993,‘Thompson and Schultz 1995). A number of the above studies measured seedlings after lifting, separated them into size classe$. and determined quality of each