acetochlor + atrazine or s-metolachlor at the leaf unfolding stage. This article investigates more chloroacetanilide herbicides; determines if atrazine contributes to leaf tatters injury; and compares white and northern red oak injury ( Quercus rubra L
Jayesh B. Samtani, John B. Masiunas, and James E. Appleby
J. Roger Harris, Jody Fanelli, and Paul Thrift
Description of early post-transplant root growth will help formulate best transplanting strategies for landscape trees. In this experiment, the dynamics of early root system regeneration of sugar maple (Acer saccharum Marsh. `Green Mountain') and northern red oak (Quercus rubra L.) were determined. Field-grown 4-year-old trees were transplanted bare-root into outdoor root observation containers (rhizotrons) in Oct. 1997, Nov. 1997, or Mar. 1998. All trees were grown in the rhizotrons until Oct. 1998 and then transplanted, with minimally disturbed rootballs, to field soil and grown for an additional two years. October-transplanted trees of both species began root regeneration earlier and regenerated more roots, as judged by accumulated root length on rhizotron windows, than Nov.- or March-transplanted trees. Median date for beginning root extension for sugar maples was 48, 22, and 0 days before budbreak for October-, November-, and Marchtransplanted trees, respectively. Median date for beginning root extension for northern red oak was 4, 21, and 14 days after budbreak for October-, November-, and Marchtransplanted trees, respectively. Height and trunk diameter growth were similar for all treatments within each species for 3 years after application of treatments. Early fall transplanting will result in earlier first season post-transplant root growth for sugar maple and northern red oak. Earlier post-transplant root growth will likely increase resistance to stress imposed by harsh landscape environments.
D.D. Crunkilton, H.E. Garrett, and S.G. Pallardy
Ectomycorrhizal and nonmycorrhizal, glasshouse-grown northern red oak seedlings (Quercus rubra L.) received root treatments of IBA in starch, fired-montmorillonite clay, or starch-encapsulated montmorillonite clay. Clay proved to be superior to starch as a carrier for IBA, inducing significant increases in diameter, root length, leaf area, and shoot dry weight. Positive growth interactions between mycorrhizae and IBA were found with the clay carrier. The typical bare-rooted red oak seedling (grown for 1 year in nurseries and outplanted) performs poorly because of insufficient root size. Container-grown seedlings produced using clay/IBA treatments may perform better under field conditions than stock grown conventionally. Chemical name used: indole-3-butyric acid (IBA).
Daniel G. Krueger Jr. and Bert T. Swanson
To increase root fibrosity, acorns of northern red oak (Quercus rubra L.) were germinated and subjected to several radicle clipping (+/-) and K-IBA concentration treatments combintations prior to planting. Taproots and laterals ≥ 1 mm in diameter at the point of origin were counted. Low concentrations of K-IBA (0-4000 ppm) resulted in four root morphologies: 1) a single taproot and 3-6 laterals (no clipping/no K-IBA), 2) 4-5 taproots and 1-3 laterals (clipped only), 3) a single taproot and 5-12 laterals (not clipped/K-IBA) and 4) 6-12 taproots and 1-2 laterals. High concentrations of K-IBA (4000-10,000 ppm) `clipped' unclipped radicles resulting in root systems similiar to those clipped by hand. Stem height was unaffected by treatment. Radicle-clipping may increase stem caliper. K-IBA treatments may decrease root dry weight.
Lisa Richardson-Calfee, J. Roger Harris*, and Jody Fanelli
Seasonal effects on transplant establishment of balled-and-burlapped (B&B) shade trees are not well documented. Early post-transplant root growth and above-ground growth over 3 years were therefore documented for November- and March-transplanted northern red oak (Quercus rubra L.) and willow oak (Q. phellos L.). Survival of red oak was 100% for both treatments. Survival of November- and March-transplanted willow oak was 67% and 83%, respectively. No new root growth was observed outside or within the root balls of either species upon excavation in January. However, new root growth was evident when subsamples were excavated the following April for November-transplanted trees of both species, indicating that root system regeneration of November-transplanted trees occurs in late winter and/or early spring, not late fall and/or early winter. November-transplanted red oak, but not willow oak, had grown more roots by spring bud break than March-transplanted trees. While height growth of willow oak was nearly identical between treatments after 3 years, November-transplants exhibited greater trunk diameter increase for all 3 years. Overall, season of transplant had little effect on height and trunk diameter increase of red oak, even though November-transplanted trees grew more roots prior to the first bud break following transplant. Among the willow oaks that survived, season of transplanting had little effect on height growth, but November transplanting resulted in greater trunk diameter increase. However, considering the mortality rate of November-transplanted willow oak, March may be a better time to transplant willow oak in climates similar to southwest Virginia.
Mindy L. Bumgarner, K. Francis Salifu, Michael V. Mickelbart, and Douglass F. Jacobs
). Tolerance to high EC is species-specific, although tolerance levels among broadleaves are not well understood ( Jacobs and Timmer, 2005 ). Thornton et al. (1988) reported that EC levels greater than 1.0 dS·m −1 caused damage to northern red oak ( Quercus
Mindy L. Bumgarner, K. Francis Salifu, and Douglass F. Jacobs
oak is selected for this study because of its economic importance and increased use in conservation plantings ( Jacobs et al., 2004 ). Materials and Methods Nursery growth and nutrition. Stratified northern red oak seeds from a single
K. Francis Salifu, Michael A. Nicodemus, Douglass F. Jacobs, and Anthony S. Davis
We evaluated suitability of chemical indices of three media formulations or substrates (A, B, and C) consisting of composted pine bark, coconut coir pith, sphagnum peatmoss, processed bark ash, and perlite in varied proportions for growing northern red oak (Quercus rubra L.) seedlings. These substrates were ranked according to their ability to promote seedling growth. The low-yielding substrate (A) was devoid of pine bark and perlite and the medium-yielding substrate (B) contained no peatmoss or processed bark ash. The high-yielding substrate (C) contained all components. Additionally, we tested plant response to high nitrogen (N) fertilization on each substrate. Media EC, pH, and total dissolved solids measured at transplanting explained 68%, 43%, and 66%, respectively, of the variation in plant dry weight and 39%, 54%, and 46%, respectively, of the variation in shoot height. Vector diagnosis effectively ranked nutritional limitations on seedling growth as N > P > K. High N fertilization highlighted element deficiency in seedlings grown on substrate A, but resulted in element toxicity and antagonistic interactions in plants established on substrates B and C, respectively.
Chris Starbuck, Daniel K. Struve, and Hannah Mathers
Two experiments were conducted to determine if 5.1-cm-caliper (2 inches) `Summit' green ash (Fraxinus pensylvanica), and 7.6-cm-caliper (3 inches) northern red oak (Quercus rubra) could be successfully summer transplanted after being heeled in pea gravel or wood chips prior to planting in the landscape. Spring harvested trees of each species were either balled and burlapped (B&B) or barerooted before heeling in pea gravel or wood chips. Compared to B&B `Summit' green ash, bareroot stock had similar survival and shoot extension for three growing seasons after summer transplanting. Bareroot and B&B northern red oak trees had similar survival and central leader elongation for 3 years after summer transplanting. In the third year after transplanting, northern red oak bareroot trees heeled in pea had smaller trunk caliper than B&B trees heeled in wood chips. These two taxa can be summer transplanted B&B or bareroot if dormant stock is spring-dug and maintained in a heeling-in bed before transplanting. This method of reducing transplant shock by providing benign conditions for root regeneration can also be used to extended the planting season for field-grown nursery stock; the method is called the Missouri gravel bed system.
Alison A. Stoven, Hannah M. Mathers, and Daniel K. Struve
Department of Agriculture. Species used in this study: Acer xfreemanii `Jeffersred' (Autumn Blaze® maple), Cercis canadensis L. (Eastern redbud), Malus `Prairifire' (Prairifire crabapple), Quercus rubra L. (Northern red oak)