Red Oak Seedlings Research Articles

Croissance, échanges gazeux et réponses nutritionnelles de jeunes semis de Quercus rubra soumis à une fertilisation par (15NH4)2SO4

We evaluated gas exchange, chlorophyll index (CI) using SPAD-502 chlorophyll meter, and leaf nutritional responses in one-year-old northern red oak (Quercus rubra L.) container seedlings transplanted into control (unfertilized) or fertilized (0.86 g N plant−1) sand culture and grown in a greenhouse for 90 days. We labeled current nitrogen (N) uptake with (15NH4)2SO4 and directly quantified proportional contributions of N derived from fertilizer (NF) compared with retranslocation or N derived from plant (NP) in leaf growth of red oak seedlings. NF met a greater N demand in leaf growth of fertilized plants while unfertilized seedlings relied entirely on NP for their leaf growth. Fertilization increased leaf dry mass by 67% and new stem dry mass by 253% 90 days after transplanting compared to control seedlings. Specific leaf area (SLA) was not significantly altered but CI increased 90 days after transplanting. Higher leaf N concentration and content in fertilized compared with control seedlings was linked to greater chlorophyll concentrations in the former plants. The higher coefficient of determination (r 2 = 0.72) noted between leaf N concentrations and CI suggests that the SPAD meter could be a useful tool for assessing leaf N status in northern red oak seedlings. Fertilized seedlings exhibited higher net assimilation, stomatal conductance, and transpiration rates compared with controls. Increased seedling growth in response to fertilization was related to maintenance of higher gas exchange and greater nutrient uptake, which could improve outplanting success.

Influences on Oak and Pine Establishment with Time Since Fire in Sandhills Pinus paulustris (Longleaf Pine) Forests

Abstract We investigated biotic and abiotic mechanisms that affect Quercus falcata (southern red oak) establishment from seeds in southeastern Pinus paulustris (longleaf pine) forests along a time-since-fire chronosequence (unburned since 1950, the mid-1990s, or winter 2001) and slope gradient. To determine if seed availability limits southern red oak recruitment, we measured seed production, populations of small mammals, and seed removal across sites. To determine if seedling survival limits establishment, we outplanted greenhouse-raised southern red oak seedlings and followed their survival throughout one growing season. We also measured abiotic conditions such as canopy openness, soil moisture, and soil temperature, and censused longleaf pine recruitment. Contrary to expectations based on species' fire-tolerances, longleaf pine recruitment was consistent over the chronosequence, but there was little oak seedling establishment in the long-unburned sites. Sites last burned in the mid-1990s had the lowest...

Growth, gas exchange, and root respiration of Quercus rubra seedlings exposed to low root zone temperatures in solution culture

Spring planting is standard operational practice in the Central Hardwood Region, though little is known about potential impacts of low root temperature (RT) common during spring on establishment success of temperate deciduous forest tree species. The effects of low RT on growth, gas exchange, and root respiration following winter dormancy were studied in 1-year-old northern red oak ( Quercus rubra L.) container seedlings grown in solution culture at uniform air temperatures, but exposed to three different root zone temperatures (10, 15, and 25 °C). After 14 days of treatment, net photosynthesis ( A), stomatal conductance ( g s), and transpiration ( E) were significantly affected by RT; however, these treatment effects did not persist for the remaining measurement period (days 21 and 28) despite growth reductions. After 28 days, new shoot length, leaf area, and number of new roots were reduced with decreasing RT. Shoot dry mass was higher in seedlings exposed to 25 °C compared with those in 10 °C, while an opposite trend occurred for root-to-shoot ratio. Leaf water potential ( ψ w) at day 28 and days to budbreak were not significantly altered by RT treatments. Root O 2 uptake in seedlings exposed to 10 °C was 65% lower than for those seedlings at 25 °C. Low RT has a physiological role in the control of root growth and root respiration, which could potentially affect establishment success of northern red oak seedlings planted in spring when soil temperatures are still low.

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Northern red oak is a valuable commercial species occurring throughout the Appalachian Coalfields Region. It reportedly grows on mined land, but little is known about preferred site and soil conditions for this species on mined land. The purpose of our field study was to test red oak survival and growth rates on a variety of topsoil substitutes. The study is located in Wise Co., Virginia on the Marcum Hollow member of the Upper Wise Formation. The site was mined in 1979 and reclaimed in 1980. In 1981, field plots were constructed with different topsoil substitutes spoil mixes and pitch x loblolly pines were planted in 1983. In 2001 the pines were removed and replaced with red oaks in the winter of 2001-2002. Four replicate plots of five different mine spoil mixes were planted with nine red oak seedlings each. Mine spoils consisted of different proportions of weathered sandstone and un-weathered siltstone. Tree survival, height and diameter were measured each year for five years. Results show that survival and growth was best on topsoil substitutes consisting of a mix of sandstone and siltstone. Trees survived and grew poorly on plots constructed from either pure sandstone or siltstone. Reasons for the poor oak performance on the high sandstone plots were not clear, but could possibly be related to lower pH and available Ca levels. Poor oak performance on the pure siltstone plots was most likely related to higher rock fragment and lower bulk water holding content.

Root characteristics and growth potential of container and bare-root seedlings of red oak (Quercus rubra L.) in Ontario, Canada

Root characteristics and field performance of container and bare-root seedlings of red oak (Quercus rubra L.) were compared during the first growing season after planting. Sixty seedlings of each stock type were planted on a clearfell and weed-free site near Restoule, Ontario. Twenty-four additional seedlings from each stock type were compared at the start of the study in terms of shoot and root parameters. Measurement of root and shoot parameters were repeated at three dates during the first growing season in the field. The root systems of container stock had a larger number of first order lateral long roots and were significantly more fibrous than bare-root stock. These differences were sustained throughout the first growing season. In terms of field performance, container seedlings had 100% survival and achieved significant increases in both biomass and shoot extension. Bare-root seedlings suffered 25% mortality, significant shoot dieback and more variable growth. The mean relative growth rate (RGR) of container seedlings increased throughout the study period to a maximum of 30 mg/g/day, whereas the mean RGR of bare-root stock remained close to or below zero. Overall, the container seedlings proved less prone to transplanting shock than the bare-root seedlings, most likely due to favourable root architecture and the pattern of root development. Further work may be warranted in container design, growing regimes and root architecture to fully realise the potential of container systems for the production of high quality red oak seedlings across a range of site conditions.

Morphological plasticity in seedlings of three deciduous species under shelterwood under-planting management does not correspond to shade tolerance ranks

The morphological plasticity of tree seedlings is considered to be an important factor in shade tolerance and plant succession dynamics. However, recent studies comparing temperate deciduous species have not found the expected relationship between plasticity and shade tolerance or successional status. We measured morphological plasticity in seedlings of three temperate deciduous species of north-eastern North America, using 13 parameters associated with growth, crown geometry, branching, and leaf arrangement, as a function of a steep light gradient (0.5–43%) in young transition forests under shelterwood management. The effects of light and seedling height were investigated using variance partitioning. We studied naturally occurring seedlings of the very shade tolerant sugar maple ( Acer saccharum), and planted seedlings of shade intolerant black cherry ( Prunus serotina) and red oak ( Quercus rubra), a species of intermediate shade tolerance. Contrary to expectations, sugar maple had the lowest light-induced plasticity and did not modify its morphology except as a function of height. It also produced relatively good growth. Moreover, black cherry displayed several unexpected characteristics, such as weak growth in response to increasing light and strong plasticity at several levels, mostly light-induced. Although red oak had a low level of overall plasticity, it produced the largest height increments under these shelterwoods. The morphological plasticity we observed lends support to models of shade tolerance which include resistance to pathogens and herbivory, and the capacity to store reserves, but still need to be supported with larger, integrated studies. Our results lead us to question how useful classic shade tolerance models based on morphological plasticity are for regeneration management and silviculture. At least under the pioneer stands we studied, both black cherry and sugar maple behaved in ways opposite to what was predicted.

Planting Oaks in Group Selection Openings on Upland Sites: Two Case Studies from Arkansas

Abstract Two upland sites in Arkansas were studied to test the performance of 1-0 northern red oak (Quercus rubra L.) and white oak (Quercus alba L.) seedlings planted in group selection openings. Both red and white oak seedlings were planted at one location in the Ozark Mountains,and only red oak seedlings were planted at a second site along Crowleys Ridge. Holes were dug with power augers and seedlings were planted by hand. At the time of planting, the mean height of red oak and white oak seedlings at the Ozark site were 3.4 and 1.9 ft, respectively. Red oak seedlingsat Crowleys Ridge averaged 3.0 ft tall when planted. After 4 years at the Ozark site, 77% of red oak and 86% of white oak were alive. After 3 years at Crowleys Ridge, red oak survival was 80%. Seedlings at both sites grew slowly. Mean 4-year height increment at the Ozarksite was 2.1 ft for red oak and 2.5 ft for white oak, and mean 3-year height increment for red oak at Crowleys Ridge was 1.6 ft. Three years after planting in the Ozark Mountains and 2 years after planting at Crowleys Ridge, naturally regenerating competition had suppressed over one-thirdof the red oak and about one-half of the white oak. This necessitated a release treatment around planted seedlings at both sites. Oaks that decreased in total height over a given growing season were common. Most seedlings that decreased in height had been pulled over or crushed by other vegetationor exhibited top dieback. South. J. Appl.For. 30(3):142–146.

Modified exponential nitrogen loading to promote morphological quality and nutrient storage of bareroot-cultured Quercus rubra and Quercus alba seedlings

Exponential nutrient loading has been used to improve nursery fertilizer uptake efficiency of conifer seedlings, but the technique has received little attention in the culture of temperate deciduous hardwoods. This study examined responses of northern red oak (Quercus rubra L.) and white oak (Q. alba L.) seedlings to modified exponential nitrogen loading during bareroot nursery culture using a broad range of nutrient supply from 0 to 3.35 g nitrogen (N) per plant per season for 18 weeks in Indiana, USA. Seedling growth and nutritional parameters followed a curvilinear pattern that ranged from deficiency to toxicity with increased fertilization consistent with trends depicted in the proposed model for nutrient loading. Fertilization increased plant dry mass by 113–260% for red oak and 49–144% for white oak. Severe nutrient deficiency occurred under indigenous soil fertility, and limited phosphorus and potassium uptake were found to inhibit seedling growth at higher N supply. The sufficiency and optimum rates were determined to be 0.84 and 1.68 g N per seedling per season, respectively, under the current cultural conditions. Fertilization at 1.68 g N per plant increased N content by 40% in red oak and 35% in white oak. This approach may be used to help refine nursery fertilization practices in hardwood culture to produce high-quality seedlings for field planting.

Evaluating Chemical Indices of Growing Media for Nursery Production of Quercus rubra Seedlings

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.

(55) Leaf Abnormality on White and Red Oak Linked to Drift of Chloroacetanilide Herbicides

In some years, the emerging leaves of white oak and, to a lesser extent, of red oak in the Midwest have developed abnormally. This abnormality is referred to as leaf tatters. Reports to state foresters and Extension specialists associated tatters with herbicide applications. In 2005, white and red oak seedlings were treated in a spray chamber delivering 187 L/ha, with seven herbicides at three concentrations, 1/4×, 1/10×, and 1/100× of the standard field use rate. These herbicides and their standard field use rate of the active ingredients included atrazine at 2.3 kg/ha and chloroacetanilide herbicides: acetochlor at 2.0 kg/ha, metolachlor at 2.1 kg/ha, and dimethenamid at 0.8 kg/ha alone or mixed with atrazine at 2.3 kg/ha, at the leaves unfolding stage. After treatment, oaks were placed outdoors in a randomized complete-block design. Leaf symptoms in our study were similar to those seen in the landscape. In chloroacetanilide-treated white and red oak seedlings, browning of interveinal leaf tissues was noticed 5–6 days after treatment. The dried leaf tissues then dropped off, leaving only the main vein with little interveinal leaf area. In few seedlings treated with atrazine, the leaf tissues turned yellow to brown, while in few others, interveinal tissue damage was restricted, leaving small holes in the leaf. When chloroacetanilide herbicides were applied with atrazine, the dominant symptoms were those of leaf tatters. A few seedlings treated with dimethenamid and atrazine had predominately atrazine symptoms. Although new growth later in the season was not injured, the leaves with tatters remained on the plant until the end of the growing season. The study will be repeated in 2006.

Impacts of deer herbivory and visual grading on the early performance of high-quality oak planting stock in Tennessee, USA

The growth of outplanted high-quality 1-0 northern red oak ( Quercus rubra L.) seedlings, growth differences between two categories of visually graded seedlings and herbivory by white-tail deer ( Odocoileus virginianus (Boddaert)) were examined after two growing seasons. Seedlings were planted in plots receiving three overstory treatments (high grade, commercial clearcut, and two age) and an uncut control on productive sites of the East Gulf Coastal Plain in Tennessee. Sixty seedlings were outplanted within each of 12 0.81-ha treatment units, resulting in three replicate blocks of the four treatments. Initial height, root-collar diameter and number of first-order lateral roots were recorded for each seedling prior to planting. Seedlings were visually graded into one of two categories (premium and good) based on morphological characteristics. Planted seedlings were measured at the end of the 2002 and 2003 growing seasons. Mean seedling survivorship after two growing seasons was 94, 92, 87 and 58% ( P < 0.001) for the commercial clearcut, two-age, high grade and uncut control units, respectively. Differences in seedling height growth were found between the harvested units and uncut control units along with a significant interaction between overstory treatment and site ( P = 0.03). Differences in seedling height were not significant among treatments involving harvest. After two growing seasons, seedlings graded as premium had produced 9 cm more height growth on average than seedlings graded as good ( P = 0.002). In addition, seedlings browsed heavily during the 2002 and 2003 growing seasons were, on average, 36 cm shorter ( P < 0.001) than unbrowsed seedlings. A significant level of mortality and diminished growth in the uncut control units suggests that pre-harvest enrichment planting without manipulating the overstory may not be a viable management option. Results from this study suggest a simple visual grading of seedlings prior to planting can result in significant growth gains early in the development of the seedlings. Further, the use of larger planting stock may have the added benefit of reducing the impacts of deer herbivory.

Organic Matter Added to Bareroot Nursery Beds Influences Soil Properties and Morphology of Fraxinus pennsylvanica and Quercus rubra Seedlings

Bareroot hardwood seedling production involves intensive soil management. To increase soil organic matter (OM), nurseries commonly grow a cover crop for 1 year after every 1–2 year of seedling production. Raising soil OM levels can also be achieved through addition of soil amendments. We studied the influence of chicken manure (CM) and composted leaf, tree, and lawn trimmings (Cp) on soil properties and morphology of green ash (Fraxinus pennsylvanica Marsh.) and northern red oak (Quercus rubra L.) seedlings. CM was applied at 725, 1450, or 2900 kg ha−1 (CM725, CM1450, and CM2900, respectively) and Cp was applied at 200 m3 ha−1. Addition of CM and Cp significantly raised soil OM levels and altered soil chemical properties compared to the control (Ctrl). Root-collar diameter increased with addition of CM1450, CM2900, or Cp compared to CM725 or Ctrl plots for northern red oak, but was largest in soils amended with CM2900 for green ash. Conversely, height was greatest with addition of CM725 for northern red oak, but green ash seedlings were shorter in Ctrl plots than in all amendments except for CM725. Root volume of green ash and northern red oak seedlings was positively influenced by addition of CM or Cp. Seedling responses to nursery soil amendments vary with different forms and amounts of OM. Benefits to seedling growth through application of appropriate materials in the proper balance can improve seedling morphological quality and positively influence soil chemical properties.

EXPERIMENTAL STUDY OF THE EFFECTS OF MAMMALIAN ACORN PREDATORS ON RED OAK ACORN SURVIVAL AND GERMINATION

A decline in the dominance of oaks (Quercus) in eastern deciduous forests generally has been attributed to herbivory by white-tailed deer (Odocoileus virginianus) or fire suppression, but few studies have considered a role for mammalian consumers of acorns. We used acorns placed on the soil surface and acorns buried approximately 2 cm underground in 4 types of exclosures to evaluate the effects of white-tailed deer, tree squirrels (Sciurus carolinensis and S. niger), and white-footed mice (Peromyscus leucopus) on survival and germination of red oak (Q. rubra) acorns. Buried acorns were intended to mimic caches of squirrels. When deer were excluded from a plot, squirrels and mice consumed or removed all surface acorns. When both deer and squirrels were excluded from a plot, mice consumed .90% of the acorns on the surface. Thus, acorn consumption by deer is unlikely to be a causal factor in the widespread decline of many oak species. Survival of buried acorns did not differ between open plots and plots where only squirrels and mice had access, but when squirrels were excluded from a plot, the survival of buried acorns increased. In addition, buried acorns germinated at a much higher rate than acorns on the surface. As suggested for many oak species, unrecovered caches of acorns are likely a critical source of red oak seedlings.

Acorn Fall and Weeviling in a Northern Red Oak Seedling Orchard

In 2000, we determined levels of damage by acorn weevils (Curculio spp.) and patterns of acorn fall in a northern red oak (Quercus rubra L.) seedling orchard in eastern Tennessee. The mean (±SE) production of acorns among 43 selected trees was 5,930 ± 586 acorns per tree with a maximum production level of 16,969 acorns for one tree. Trees were selected in the spring of 2000 based on abundance of acornets. The mean (±SE) damage level to acorns was 33 (±2) percent (determined by dissection). The floating method for assessing sound acorns overestimated acorn damage by 36 percent overall. Weevils accounted for approximately 66 percent of all damage to acorns. We found that the percentage of weeviled acorns was negatively correlated to total acorn production per tree. The rate of acorn drop was higher in October and November than in September. However, the percentage of acorns damaged by weevils was higher for acorns falling in September than for acorns falling in October or November.

Effect of Bioplex™ on Transplant Success of Non-Dormant Red Oak (Quercus rubra L.)

Abstract Biostimulants are used to reduce the stress associated with non-dormant (summer dug) harvest of field-grown nursery stock; however, the effectiveness of biostimulant treatment is uncertain. This study tested the effects of three application methods of Bioplex™ (a commonly used biostimulant) to container-grown red oak seedlings on whole plant transpirational water use and growth before and after root pruning. Root pruning was used to simulate field harvest; it removed 59% of the seedling's total root surface area. Bioplex™ application by foliar spray, soil drench or a combination of foliar spray and soil drench, significantly reduced whole plant transpirational water use by 15% for three days after application, relative to untreated control seedlings. Root pruning significantly reduced whole plant transpiration, compared to non-root-pruned seedlings, and had a greater effect on transpiration than any Bioplex™ treatment. The previous season's Bioplex treatment had no effect on the spring growth flush following fall root pruning. Root pruning in fall significantly reduced root and total plant dry weights the following spring. Although Bioplex™ applications significantly reduced transpiration for three days after application, there does not seem to be any long-term beneficial effect when used to mediate summer digging transplant stress.

Differential Activity of Peroxidase Isozymes in Response to Wounding, Gypsy Moth, and Plant Hormones in Northern Red Oak (Quercus rubra L.)

We measured total peroxidase activity and the activities of peroxidase isoforms in leaves of red oak (Quercus rubra L.) seedlings exposed to wounding and plant hormones in the greenhouse. Activity of specific peroxidase isoforms was induced differentially by gypsy moth wounding, mechanical wounding, and the wound-associated plant hormone jasmonic acid. Activity of one isoform was enhanced modestly by treatment with salicylate. A study of peroxidase activity in naturally occurring galls elicited on red oak leaves by 12 hymenopteran and dipteran insect species found 16 POD isoforms, 11 of which were differentially induced or suppressed in galls compared with leaves. In both studies, total peroxidase activity as measured spectrophotometrically was not clearly related to activity of these isoforms. These results indicate that red oak seedlings and trees may respond specifically to wounding, particular insects, and plant signals through changes in the activities of individual isozymes.

Effect of a strong cold storage induced desiccation on metabolic solutes, stock quality and regrowth, in seedlings of two oak species

Bare-root seedlings of pedunculate oak (Quercus robur L.) and northern red oak (Quercus rubra L.) were lifted in January and stored at 1.8°C, at 82% relative humidity, until their fresh weight declined by 33%. Root growth potential (RGP), fine root electrolyte leakage (REL), fine root water content (RWC), shoot tip water content (SWC), starch and metabolic solute contents in root and shoot, were measured just after lifting and after treatment. Survival of treated seedlings was also assessed in a field trial. RWC, SWC, REL, RGP were dramatically affected by desiccation during cold storage. In both species, root soluble carbohydrate level, inositol level and isocitrate level increased, whereas root starch level and shoot soluble carbohydrate level decreased. In northern red oak, treated seedlings had higher root contents of soluble carbohydrates, inositol and proline than in pedunculate oak. Moreover, treatment induced proline accumulation only in northern red oak roots. These differences could explain why field survival of treated seedlings was significantly better in northern red oak than in pedunculate oak.

Auger Planting of Oak Seedlings

Abstract In 2001, we used power augers to plant 1-0 northern red oak (Quercus rubra) and white oak (Q. alba) seedlings in stony soils in Arkansas. After two growing seasons, red oak and white oak survival was 86% and 91%, respectively. Both species had only grown an average of 1 ft in height in 2 yr. North. J. Appl. For. 20(2):92–93.

Impacts of Hay‐Scented Fern on Nutrition of Northern Red Oak Seedlings

A greenhouse study was conducted to assess the impacts of hay‐scented fern (Dennstaedtia punctilobula [Michx.] Moore) on the nutrition of first‐year, northern red oak (Quercus rubra L.) seedlings. Four common forest soil types in Pennsylvania were chosen as growth media for the study—two nutritionally poor soils and two moderately nutritional soils. Oaks and ferns were grown separately and together. Total macronutrient content [phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg)] was positively and significantly related to biomass in red oak, but not in ferns. Oaks grown with ferns exhibited greater nutrient imbalances and diminished nutrient status compared to oaks grown alone on all four soils. When grown with ferns, oak foliage exhibited significantly lower concentrations of K on all four soils, lower nitrogen (N) on three of four soils and lower P on two of four soils when compared to oaks grown alone. Conversely, ferns grown with oaks had fronds with significantly higher concentrations of N and K on all four soils and higher P on three of four soils. Differential nutrient capture between hay‐scented fern versus oak seedlings was evident in this study and interspecific competition from hay‐scented fern was shown to alter the nutritional balance of red oak seedlings. Hay‐scented fern exhibited a competitive advantage over red oak in maintaining growth and acquiring nutrients and nutrient competition was identified as a specific mechanism of below ground interference by hay‐scented fern.

Competitive Capacity of Quercus rubra L. Planted in Arkansas' Boston Mountains

Abstract Results of an 11 yr study of the growth and survival of planted northern red oak (Quercus rubra L.) seedlings (2-0 bare-root) are presented. More than 4,000 seedlings were planted under shelterwood overstories that were harvested 3 yr after planting. Results are expressed as planted-tree dominance probabilities. Dominance probability is the probability that a planted tree will live to attain a favorable competitive position (i.e., at least 80% of the mean height of dominant competitors) at a specified year. We interpret the resulting probability as a measure of the competitive capacity of an individual seedling, i.e., its potential of attaining dominance in a specified environment. Based on logistic regression analysis, dominance probabilities increase with time after shelterwood overstory removal for any given environment and initial seedling characteristics. At any specified time, dominance probabilities depend on initial seedling basal diameter before planting (stem caliper 2 cm above the root collar), site quality, intensity of weed control, and shelterwood percent stocking. Dominance probabilities increase with decreasing shelterwood stocking, increasing initial stem caliper, and increasing intensity of weed control. Other factors being equal, top clipped seedlings have higher dominance probabilities than unclipped seedlings. The reciprocals of the dominance probabilities provide silviculturally useful estimates of the numbers of trees that would need to be planted to obtain, on the average, one competitively successful tree. For example, if clipped seedlings averaging 6 mm in caliper were planted where oak site index was 24 m, shelterwood stocking was 80%, and the site was given no weed control before or after planting, obtaining one competitively successful tree 11 yr after planting (8 yr after shelterwood removal) would require planting 144 seedlings. Other factors remaining the same, increasing initial caliper to 22 mm would require planting only 5 trees to obtain 1 competitively successful tree. For the same size (22 mm) and type of seedling planted on site index 18 m under a shelterwood at 40 to 60% stocking and given two weed control treatments, only 1.4 trees would need to be planted. Results emphasize the sensitivity of competitive capacity, and thus the silvicultural potential, of planted northern red oaks in the Boston Mountains of Arkansas to the joint effects of field environment and initial seedling characteristics. FOR. SCI. 48(3):504–517.