David South

Auburn University | AU · School of Forestry and Wildlife Sciences

The optimum seedling is defined as the ideotype that will minimize overall reforestation costs while achieving established goals for initial survival and growth (South and Mitchell 1999). Nursery stock may vary in size from seedlings that have a 2 mm root-collar diameter (RCD) to seedlings that have a 13 mm RCD. RCDlob is a growth and yield program...

This review provides information and opinions about irrigation practices in pine nurseries. Even when nurseries receive more than 15 mm of rainfall week-1, managers irrigate seedbeds to increase germination, increase seed efficiency, and increase root growth. In the southern United States, a 7-month old pine seedling in an outdoor nursery typically...

Two schools of thought address the optimum soil pH (measured in water) for growing hardwood seedlings in bareroot nurseries. One school uses nutrient surveys in non-fertilized forests to determine the best pH range for growing seedlings in fertilized nurseries. Some students of this school believe hardwood seedlings grow best at pH 6.0 to 7.5. In c...

Sulfur and lime experiments at a sandy nursery in Texas detected no significant rate effect on height, root-collar diameter, or seedling mass of 1-0 loblolly pine (Pinus taeda L.) seedlings. Location of replications, however, had a large effect (P < 0.001) on seedling growth, which was related to nutrient levels in the soil. Positive correlations o...

Although the production of commercial products of vegetative Pt (Pisolithus tinctorius (Pers.) Coker & Couch) inoculums has ceased in North America due to a lack of demand by consumers, the number of products that contain Pt spores has increased. The quality, quantity and price of these products vary considerably. The cost of inoculating 1,000 tree...

In North America, most tree nursery nutrition publications during the past two decades involved either container-grown stock or stock grown in greenhouses. In contrast, most bareroot nursery fertility trials in North America were published during the last century. As a result, some bareroot fertilization recommendations have remained the same since...

When it comes to testing for differences in seedling survival, researchers sometimes make Type II statistical errors due to the inherent variability associated with survival in tree planting studies. For example, in one trial (with five replications) first-year survival of seedlings planted in October (42 percent) was not significantly different (a...

Two pH experiments were conducted at a sandy, bareroot loblolly pine ( Pinus taeda L.) nursery in Texas. A sulfur trial (0, 813, 1626, 2439 kg ha -1 of elemental sulfur) was installed to determine if lowering soil pH would result in nutrient toxicity symptoms and affect seedling morphology. Although soil acidity in the sulfur study ranged from pH 3...

When it comes to testing for differences in seedling survival, researchers sometimes make a Type II statistical error (i.e. failure to reject a false null hypothesis) due to the inherent variability associated with survival in tree planting studies. For example, in one trial (with five replications) first-year survival of seedlings planted in Octob...

Over the past five decades, researchers in the southern United States have been working with nursery managers to develop ways to reduce the cost of producing seedlings. In this regard, the Southern Forest Nursery Management Cooperative (at Auburn University in Alabama) has helped reduce hand-weeding costs and losses due to nematodes and disease. As...

During the last half of the 20th century, southern yellow pine (Pinus subsection Australes) timberland in North America declined by 16 million acres (3.6 million acres per decade). Declines in acreage in the South have continued in the 21st century for five pine forest types. In contrast, increases in timberland (due to tree planting) have occurred...

Block-plot experiments in Alabama and Georgia were examined to determine the effects of transplant size on early height growth of a tissue-cultured, Pinus taeda L clone. Ramets of clone L-3576 (miniplugs) were transplanted into a bareroot nursery at three spacings. After lifting, the transplants were sorted into three classes according to the diame...

The management of forests is directly related to the landowner’s objective, and to some extent, the type of economic system employed by the landowner. The system used to manage government forests is typically different than that used by industrial landowners. Likewise, the system used by large estate owners may differ from that used by industry. Th...

This review compares fall acclimation patterns and lift/store practices for Pseudotsuga menziesii var. menziesii, Picea glauca (Moench) Voss x P. engelmannii Parry ex engelm and Pinus taeda L. seedlings. Spruce seedlings achieve budset and an endodormant state in late summer, coastal Douglas-fir in early fall, while loblolly pine achieves a less en...

Pine branches, pine logs, and residues from sawmills have been burned for energy for over a thousand years. This chapter discusses phylogeny, chemical composition, heat of combustion, growth, energy yield, nursery production, planting season, density and row configuration, weed control, fertilization, insect and disease control, resin management, h...

Two studies were established to determine the effects of planting depth on early performance of bareroot shortleaf pine seedlings (Pinus echinata). The studies involved planting seedlings either with the root-collar slightly below the groundline (GL) or with the root-collar planted about 11 cm below the soil surface (DEEP). After transplanting, DEE...

The cost of establishing longleaf pine (Pinus palustris Mill.) on agricultural sites is typically higher than that for slash pine (Pinus elliottii var. elliottii Engelm.). For some landowners, this cost might be reduced by establishing a two-species plantation (e.g., planting one-third to one-half of the rows with slash pine). To examine the potent...

When conducting inventories, reducing variability among tree diameters, heights, and ultimately volumes or biomass, can reduce the number of points/plots needed to obtain a desired level of precision. We present a simple analysis examining the potential reduction in discounted inventory costs when stand variability is decreased (via improved geneti...

Cold storing bareroot southern pine (Pinus spp.) seedlings for greater than one week after lifting in the fall can lead to poor outplanting survival when compared to seedlings that are lifted and stored in winter. In contrast, container-grown seedlings typically do not experience adverse effects from storing for periods greater than one week. The p...

Many root hydrogel compounds are available for seedling nurseries for root treatment at the time of packing. They can differ based on composition (starch-based versus polyacrylamide), grade (fine, medium, or coarse), or by their range of particle size distributions. While the use of root hydrogels at the time of lifting, packing, and storing is a v...

Cold storing bareroot pine (Pinus spp.) seedlings grown in the southern U.S. for as little as 1 week in a cooler (just above freezing) in the fall (November to mid‐December) has been shown to reduce seedling survival after outplanting. In contrast, survival of container‐grown seedling is typically not affected when stored for 4 weeks in coolers in...

Pinus taeda L. plantations in the United States are typically established using rows that are spaced 3 to 4 m apart. Although one company now plants pines in 6.1 m rows, reports on performance using this row spacing are rare. This paper provides a case study (established at the Solon Dixon Forestry Education Center) that compares two densities [672...

Scalping is a mechanical process whereby the soil is peeled back in a shallow (5 to 10 cm [2 to 4 in]) furrow that is 75 to 90 cm (30 to 35 in) wide. Scalping is often recommended prior to planting longleaf pine (Pinus palustris Mill. [Pinaceae]) on pastures and land formally occupied with row crops; however, some reports suggest that growth of pin...

Four seedling conditioning treatments and four fall fertilization treatments were applied to loblolly pine (Pinus taeda L.) seedlings in a bare-root nursery in Alabama. Three conditioning treatments involved undercutting plus root wrenching (two, four, and six times), and a fourth treatment included top-pruning (three times) and no undercutting. Fe...

A rapid bioassay developed for testing photosynthesis-inhibiting herbicides was adapted for use with pine cotyledon tissue. Several herbicides having different modes of action were tested using loblolly pine (Pinustaeda L.) cotyledons. In addition to being a promising bioassay method for determining pine tolerance of photosynthesis inhibitors, diff...

Pine-seedling tolerance to preemergence applications of herbicides was examined in field experiments conducted on loblolly (Pinustaeda L.), slash (Pinuselliottii Engelm. var. elliottii), shortleaf (Pinusechinoto Mill.), and eastern white pine (Pinusstrobus L.) at six southern forest nurseries in 1976 and 1977. Herbicides suitable for preemergence u...

Tests with 4-month-old loblolly pine (Pinustaeda L.) seedlings grown in the greenhouse show decreased short-root formation when grown in soil treated with the root-inhibiting herbicides trifluralin and napropamide. However, short-root development of treated seedlings did not differ from controls after 7 months. Percentage of bifurcate roots of 7-mo...

Pine seedling tolerance to postemergence applications of herbicides was examined in field experiments conducted on loblolly (Pinustaeda L.), slash (Pinuselliottii Engelm. var. elliottii), longleaf (Pinuspalustris Mill.), and eastern white pine (Pinusstrobus L.) at eight southern forest nurseries in 1976 and at five nurseries in 1977. Herbicides sui...

Initial planting height of loblolly pine (Pinustaeda L.) seedlings from several nurseries and seed sources was related to survival and height growth on "good" and "poor" planting chances in Alabama. A planting chance was classified as poor if 2-year survival was less than 75% and total 2-year height growth was less than 75 cm. Seedling height (meas...

Container-grown seedlings of Pinustaeda L. with well-formed terminal buds, feather-tops (a succulent shoot tip crowned with a tuft of primary needles), and terminal buds removed (debudded) were sampled in November, December, and January. Root growth potential for unstored and stored seedlings was measured to determine if it is affected by shoot tip...

The influence of initial seedling diameter on survival was significant. Seedlings with a 2-mm groundline diameter averaged 62% survival, whereas 5-mm seedlings averaged 85% survival. Use of large-diameter stock improved survival regardless of soil cultivation or weed control treatments. For survival, there was an interaction between soil cultivatio...

Researchers in New Zealand, Scotland, South Africa, Texas, and Alabama provided data on growth responses owing to nursery management practices and weed control after outplanting. Nursery treatments included nitrogen fertilization (0 vs. 168 kg/ha), seedling grades (small-diameter vs. large-diameter seedlings), and a comparison of stock types. Weed-...

Managers are typically interested in using equations that provide accurate volumes for large, merchantable trees while modelers are often more interested in equations that meet statistical assumptions. Therefore, modelers often use weighted (WLS) rather than ordinary least squares (OLS) to fit individual tree volume equations since the random error...

Observations over the past three decades indicate that waterlogged conditions in bareroot nurseries can adversely affect the survival of transplanted Pinus taeda L. seedlings. Waterlogged seedbeds can develop when frequent rains occur over an extended period of time. Anaerobic conditions may occur when warm soils remain saturated for just a few day...

Forest researchers frequently use mean relative growth rates to compare growth of seedlings that differ in initial size. Reasons for using the technique include: 1) to eliminate any size-related growth differences, and 2) to determine which seedlings are inherently more “efficient.” Although this technique is based on the theory that tree growth oc...

The effects of nursery practices on freeze tolerance of P. taeda and P. elliottii seedlings were examined by placing the seedlings in a freezing chamber and lowering the temperature to -10°C. Injury was evaluated 10 days after the freeze treatment by examining cambial tissue (browning test). Top-pruning P. taeda seedlings (three times) increased fr...

Pot-binding can adversely affect the performance of container-grown stock. One factor that affects pot-binding is the size of the root system in relation to the size of the container. The aim of this study was to determine if an objective root-bound index (RBI) would be useful when evaluating the quality of pines grown in various types of container...

Roots of pine seedlings can be injured by freezing temperatures and the degree of injury is affected by genotype and stage of acclimation. Local sources of Pinus echinata and P. virginiana that were acclimated by cold temperatures were relatively freeze tolerant when grown in nurseries located where average minimum temperatures ranged from –18 to –...

Pendimethalin is used by some nursery managers to control weeds in Eucalyptus and Pinus seedbeds and cutting beds of Pinus. Six trials were implemented in open-rooted seedbeds to test the response of Pinus taeda to postemergence (to the crop) applications of 2.2 kg ha-1 active ingredient of pendimethalin (the formulation contained 455 g l-1). No st...

An assumption of ordinary least squares (OLS) is constant variance across the domain of a regressor. Often, however, the random error term variance is not constant when modeling biological data and therefore weighted least squares (WLS) is commonly used to estimate parameters. Less emphasis is placed on observations of the dependent variable with l...

Weeds have existed in nurseries since before the time Bartram grew hardwoods during the 18th century. Hand weeding was the primary method of weed control during the first part of the 20th century. From 1931 to 1970, advances in chemistry increased the use of herbicides, and advances in engineering increased the reliance on machines for cultivation....

Hydrogels and clay slurries are the materials most commonly applied to roots of pines in the southern United States. Most nursery managers believe such applications offer a form of "insurance" against excessive exposure during planting. The objective of this study was to examine the ability of root dip treatments to: (1) support fungal growth; and...

An individual tree model for loblolly pine (Pinus taeda L.) was developed to predict the response resulting from varying root-collar diameter (RCD) at time of planting. Data for this model were obtained from four plantations in the Lower Atlantic Coastal Plain of the United States. The study involved two levels of silvicultural intensity (1- standa...

Nursery trials were conducted in 2005 and 2006 to determine the tolerance of bare-root loblolly pine (Pinus taeda L.) seedlings to the herbicide MSMA. Seedlings in five nurseries were treated 4 to 14 weeks after sowing at rates up to 2.24 kg/ha. Seedlings sampled in the fall showed no signs of shoot or root injury. MSMA treated seedlings were not s...

Only a few growth and yield programs allow users to model the effects of hardwood competition on yields from pine plantations. Several of these programs were developed with the assumption that reducing hardwood competition would consistently produce a Type 2 growth response where pine volume gains increase over time. However, the actual response is...

Longitudinal sections revealed that radicles of laboratory-grown slash ( Pinus elliottii Engelm.) and loblolly ( Pinus taeda L.) pine and lateral roots of naturally-grown and container-grown loblolly pine developed a rootcap that was 3-8 cell layers wide around the root proper at the level of the quiescent center and 8-32 cell layers from the quies...

Because of concerns over the ozone layer, the annual amount of methyl bromide used for soil fumigation for crop production is decreasing. A promising alternative soil fumigation treatment involves applying 300 lb/ac of chloropicrin (CCl3NO2) under a plastic tarp. Although this soil fumigant does not control weeds as well as an equivalent amount of...

Harvest age, summer rainfall amounts, and genetics can affect wood density much more than the number of trees planted per acre. Landowners, therefore, need not be concerned about spacing affecting specific gravity when their objective is to plant at a wide spacing to produce more sawlogs (if the rotation age is not shortened). If landowners want to...

Certain types of chemicals can affect the gravitropism of roots. In a laboratory study, intact loblolly pine (Pinus taeda L.) radicles (emerged from H2O2-treated seeds) exhibited positive gravitropism 8 h after horizontal placement in sterile conditions. The growth angle decreased from almost horizontal (85 degrees) to 21 within one week after trea...

Despite the fundamental importance of gravity-driven growth response in plants, the mechanisms that result in root geotropism are poorly understood and the signaling pathways involved remain elusive. Therefore, we reviewed root gravisensing structures and theories (or propositions) explaining root growth geotropism in directions of genetics, physio...

Colorless, euhedral crystals were abundant on the roots of chlorotic pine seedlings from one nursery in Georgia and one in Alabama in 1998. Energy dispersive spectroscopy indicated these crystals were rich in calcium (Ca) and sulfur (S), and single crystal x-ray diffraction determined the crystals to be CaSO4·2H20 (gypsum). These crystals had forme...

The initial effects of a silvicultural treatment on height or volume growth sometimes decline over time, and the early gains eventually disappear with very long rotations. However, in some reports initial gains are maintained until harvest but due to statistical analyses, a researcher might conclude the treatment effect has “washed-out” by ages 10...

Some researchers claim that continuously increasing intensive plantation management will increase profits and reduce the unit cost of wood production while others believe in the law of diminishing returns. We developed four hypothetical production models where yield is a function of silvicultural effort. Models that produced unrealistic results wer...

When the landowner's objective is to maximize the net present value of a longleaf pine (Pinus palustris P. Mill. [Pinaceae]) plantation, most tree planting recommendations can be placed into 1 of 2 schools of thought. Those from the "plant-'em thick" school recommend planting more than 1483 longleaf pine trees/ha (600/ac). Some from this school say...

Although gravitropism of maize (Zea mays L.) roots is dependent on light, it is not known if light affects the gravitropism of pine radicles. Therefore, seeds of slash pine (Pinus elliottii Englm.) and loblolly pine (Pinus taeda L.) were germinated under constant light or constant darkness. A gravitropic set-point angle (GSA) of 90° indicates the r...

Integrated Pest Management is a system that combines cultural, biological and chemical technologies to reduce insect, fungal and weed populations to levels below those that result in economic damage. Nursery managers in the southern United States currently use many practices to control pests of southern pine seedlings. Over the last three decades,...

Gains in stand volume that result from competition control and fertilization are sometimes reported as ‘percentage gains’. Because percentage gains arithmetically decline over time as stand volume increases, plantation managers have difficulty in using percentage gains to project growth and revenues. The ‘age-shift’ method quantifies the year advan...

Four outplanting experiments in the North Island of New Zealand were examined to determine the effects of stock size on survival and early height growth of rooted fascicle cuttings of Pinus radiata D. Don. Survival and third-year tree height were examined in relation to (a) initial diameter, (b) initial height, (c) initial diameter squared, (d) bul...

Two stock types of loblolly pine (Pinus taeda L. [Pinaceae]) were outplanted at 3 spacings: 749, 1122, and 1497 trees/ha (303, 454, and 605 trees/ac). Morphologically improved seedlings were grown at a density of 177/m2 (16/ft2) while standard seedlings were grown at a density of 277/m2 (25/ft2). Morphologically improved seedlings had an average ro...

Proponents of intensive plantation management do not all use the same type of response curves when predicting future volume gains. As a result, some believe that continuously increasing the intensity of management will increase landowner profits and reduce the unit cost of wood production (i.e. all silvicultural costs per ha/merchantable cubic metr...

Three hardwall container types, one styroblock® container type, and two mesh-covered plugs were used to grow longleaf pine (Pinus palustris Mill.) seedlings at a nursery in Louisiana. In 2001, these container types, along with bare-root seedlings (from a different seed source), were outplanted on two old-field sites and two cutover sites. There wer...

Two stock types of loblolly pine (Pinus taeda L. [Pinaceae]) were outplanted at 3 spacings: 749, 1122, and 1497 trees/ha (303, 454, and 605 trees/ac). Morphologically improved seedlings were grown at a density of 177/m2 (16/ft2) while standard seedlings were grown at a density of 277/m2 (25/ft2). Morphologically improved seedlings had an average ro...

On some reforestation sites, the planting of large-diameter seedlings can lower establishment costs by reducing the need to apply extra chemicals to increase the performance of regular seedlings. On five sites, survival of large-diameter Pinus taeda L. or P. elliottii Englem. seedlings (average root-collar diameter 8.1 to 9.2 mm) was equal or great...

Hexazinone, premixed with controlled release carriers, was applied to charcoal root-dipped, sycamore seedlings in field studies conducted in 1997 and 1998. The objective was to determine the combined effects of the carriers and root dips on herbaceous weed control and seedling growth and survival. Two controlled release carriers, methylated seed oi...

Methodology for the Statistical Analysis Software package is presented to determine the power of completely randomized factorial and randomized factorial block designs. The code can be used to calculate power for any number of factors and their interactions within these two designs.

Improving seedling performance by reducing seedling height can be an important aspect of nursery management. The plant growth regulator uniconazole was applied to regulate height growth of nursery-grown loblolly pine (Pinus taeda L.) seedlings. Tests involving a foliar spray (0, 0.125, 0.25, 0.5 and 1.0 kg ai/ha) or a wick application (0, 125, 250,...

A proposal by IUFRO-SPDC to reduce the turnaround time for submitted manuscripts on forestry is discussed. The project is the single largest specific-purpose project ever implemented by IUFRO-SPDC, commenced in January 2000 and provided a total of 1 million EURO for developing the African component of the Global Forest Information Service. With two...

Three studies in the Coastal Plain of Georgia were remeasured 7 or 8 years after planting to determine the effects of planting depth on field performance of open-rooted seedlings [root-collar diameter (RCD) ≤ 5 mm]. Average planting depth (i.e, shoot height before planting minus shoot height above ground after planting) for machine planted P. ellio...

Abstract—Many loblolly pine (Pinus taeda L.) plantations are established at row spacings of 8 to 12 feet, but some companies are now using rows spaced 14 to 18 feet apart. Wide rows reduce establishment costs when sites are bedded, ripped, or machine planted. The cost of chemicals is also reduced when treatments are applied in bands along the row....

A somewhat poorly-drained site in the Georgia flatwoods was prepared with single- and double-bedding and was planted with slash pine (Pinus elliottii Engelm.) seedlings in October. Half of the plots were treated with imazypyr in March. Double-bedding increased 7th year volume by 5 m3 per ha, but due to insufficient control of gallberry [Ilex glabra...

Statistical power tests were conducted on 17 herbicide trials in southern pine nurseries. Tests with low power can have a high probability of a Type II error (i.e. rejecting a true alternative hypothesis). Improvements in experimental design (e.g. increasing the number of experimental units or adequately lowering error sum of squares by blocking or...

A mixed planting (50% longleaf pine and 50% slash pine) is proposed to lower the cost of establishment of longleaf pine stands. This "two-species" plantation is established by alternating rows of longleaf pine and slash pine. The slash pine can be considered a trainer" species since the objective is to remove all the slash pine during the first com...

The factors on which the planting density for Loblolly pine depends are discussed. Low planting rates are preferred if the objective is to optimize sawlog production with reduced establishment costs. Since transportation costs can eat up the value of pulpwood, it makes more sense to grow mostly saw timber and chip-n-saw if the land is far from a ch...