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A study to determine the effects of environmental conditions on the growth of longleaf pine (Pinus palustris Mill.) was initiated in 1969 on the Escambia Experimental Forest near Brewton, Alabama, USA. This study sample consisted of forty young naturally regenerated, even aged longleaf pine seedlings evenly divided between two soil types. At the beginning of the study, the seedlings were 14 years from seed and ranged in height from 0.8 to 1.5 m. From 1969 to 1970, height and diameter measurements were recorded once to four times weekly during the growing seasons and once a month during the dormant seasons. To test the effects of shading on growth, cheesecloth was suspended over 10 randomly selected seedlings from each soil type only during the first growing season, from March 28 to September 24, 1969. This study provides data from the only known in-field shading experiment with longleaf pine seedlings of this size. The effects of the shading treatment and soil type were evaluated for height and diameter growth. The shading treatment did not have a significant effect on either height or diameter growth, but soil type had a significant effect on diameter growth. Key words: Pinus palustris, longleaf pine, shade, soil type, shade intolerance.

Sphyrapicus varius (Yellow-bellied Sapsuckers) are winter residents of mature Pinus palustris (longleaf pine) forests in the southeastern US. Sapsuckers pierce the bark of mature pines to create wells on living trees and consume the sugar-rich exudate and insects attracted to this food source. To determine sapsucker preferences for individual trees, for locations along boles, and for edge vs. interior habitat, we surveyed an old-growth Pinus palustris stand in lower Alabama with recent sapsucker activity. Individual tree characteristics and stand conditions were evaluated to assess their influence on the number and location of sap wells. Of 596 pines sampled, 74 (12.4%) contained wells. Sapsuckers selected trees with greater diameter at breast height (mean dbh of welled trees = 40.4 cm; non-welled trees = 24.6 cm; P < 0.01). Among pines with wells, sapsuckers fed differentially on different aspects and stem heights. Sap wells were concentrated on the north aspect of the bole (P < 0.05), where wel...

La croissance de Pinus taeda L., avec et sans controle de la vegetation herbacee competitive, a ete evaluee sur une periode de 15 ans a des densites de plantation variant de 747 a 2990 arbres/ha. La croissance en hauteur qui atteignait 0,9 m a l'âge de 5 ans en reponse au controle de la vegetation est tombee a 0,3 m a l'âge de 15 ans. La convergence de la hauteur cumulative des peuplements traites avec celle des peuplements non traites ne s'est pas transposee a la surface terriere et au rendement en volume. Avec 1500 et 2200 arbres/ha la croissance en volume en reponse a un controle hâtif de la vegetation a augmente jusqu'a l'âge de 15 ans. Avec 800 arbres/ha, les gains en volume ont augmente jusqu'a l'âge de 12 ans et sont demeures stables entre les âges de 12 et 15 ans. Les densites plus elevees ont apparemment permis de capturer davantage de ressources du site rendues disponibles grâce au controle de la vegetation. Les gains en volume a l'âge de 15 ans avec 2200, 1500 et 800 arbres/ha etaient respectivement de 71 (23%), 48 (17%) et 19 (8%) m 3 .ha -1 . Un terme d'ajustement distinct dans les modeles pour la hauteur et la surface terriere a permis de faire ressortir l'effet positif du controle de la vegetation a court terme sur la croissance en hauteur et a long terme sur la surface terriere. Les modeles pour la hauteur et la surface terriere publies precedemment ont ete modifies pour tenir compte des effets de la densite de plantation.

In 1973, a study was established in south-central Alabama, U.S.A., to determine the effects of hardwood control treatments on understory succession and overstory growth in natural stands of longleaf pine (Pinus palustris Mill.). The treatments were seasonal biennial burns and a no-burn check, each combined with three supplemental hardwood control treatments (one-time chemical, periodic mechanical, and untreated check). Green vegetation less than 1 cm DBH and organic litter were destructively sampled to determine the effects of 23 years of treatments on understory vegetation and identify changes in this community since last sampled in 1982. Among the hardwood control treatments, the only significant differences occurred in the shrub and green biomass (total of tree, shrub, woody vine, and herbaceous species masses) component of the understory. There were significant differences for all vegetation components when comparing the burning to no-burn treatment. Green biomass estimates were variable but showed an increase for all but two of the 12 treatment combinations when compared to 1982 biomass. The major change occurred in the accumulation of organic litter, which increased 119% when averaged across all treatments. The chemical treatment did not eliminate any species when compared with the other hardwood control treatments.

An individual tree annual survival rate model was developed for naturally regenerated, even-aged longleaf pine (Pinus palustris Mill.). Development was based on 44,000 survival observations on 15,000 trees occurring on 202 permanent sample plots located in central and southern Alabama, southern Mississippi, southwest Georgia, and northern Florida. Variables used in the model were predicted diameter increment and diameter at breast height (dbh). Predicted annual survival rates ranged from 0.92 for a tree with a 1 in. dbh and an annual diameter increment of O.05 in., to over 0.99 for any tree larger than 6 in. in dbh. Stand level verification was based on 102 comparisons of observed and predicted trees per acre (tpa). Mean residuals, expressed as a percentage of observed final tpa, were 3% and 6% for projection periods of 5 and 10 yr, respectively. The model predicts noncatastrophic mortality. In conjunction with a basal area increment model, it can be used to predict changes in the structure of longleaf pine stands. South. J. Appl. For. 21(2):97-101.

A table for estimating longleaf pine (Pinus palustris Mill.) pole classes in the field is presented. The table was derived by converting the American National Standards Institute's dimensions of southern pine poles from minimum circumference at 6 ft from the butt of the pole to minimum tree diameter breast height outside bark. The conversion is based on tree taper, stump height, length trimmed off the butt of the tree at the pole yard, and bark thickness. The table is compared to a previously published table for determining southern pine pole classes from dbh. South. J. Appl. For. 16(2):79-82.

Loblolly pine (Pinustaeda L.) seedlings from two families differing in ozone sensitivity were exposed to four ozone concentrations (charcoal-filtered (subambient ozone concentration), nonfiltered (ambient ozone concentration), non-filtered × 1.7, and nonfiltered × 2.5) and three levels of acidic precipitation (pH = 3.3, 4.3, and 5.3) in modified open-top chambers for one growing season at Auburn, Alabama. Seedlings were planted in the ground in root-exclusion tubes that isolated root systems of individual seedlings. Foliage, stem, and root biomass, three-dimensional root surface area (root surface area × π; in cm3), final height, and groundline diameter were recorded and analyzed. Foliage dry matter and root surface area decreased and root to shoot ratio significantly increased with increasing ozone concentrations for the ozone-sensitive family. There were no significant pH effects for this family. No significant differences in either ozone or pH treatments occurred for the ozone-tolerant family. The possible implications on long-term effects of ozone and acidic precipitation on loblolly pine growth are discussed.

Data were collected on open-grown loblolly pine (Pinustaeda L.), longleaf pine (Pinuspalustris Mill.), and shortleaf pine (Pinusechinata Mill.) and analyzed to provide predictive equations of crown width and maximum potential basal area growth for crown competition and growth and yield models. The measurements were taken on 115 open-grown loblolly pine trees and 76 shortleaf pines in southeastern Arkansas. The longleaf pine data consisted of 81 open-grown trees from southern Alabama, Georgia, and Florida. A circle and an ellipse were tested as geometric models of the vertically projected crown. No significant differences between the tree shapes were found based on analyses of length and azimuth of the largest crown diameter, and the circle was chosen as an appropriate model. This indicated that only the distance between trees, not their orientation to one another, need be included in models of crown competition based on crown contact. Predictive equations of mean crown width based on diameter at breast height were fitted for each species for use in models of crown competition. A Chapman–Richards growth rate function with an intercept term was fit to periodic annual inside-bark basal area growth based on initial inside-bark basal area to provide empirical estimates of maximum basal area growth rates for growth and yield modeling of the given species. Additionally, equations to predict double bark thickness as a function of diameter at breast height were fit for each species to facilitate the use of the equations with outside-bark measurements of diameter.

Monthly diameter 2 × height ( d 2 h ) data were measured over two years in open-top chambers at Auburn University, Alabama. This study exposed seedlings from two half-sibling loblolly pine ( Pinus taeda L.) families to ozone and acid precipitation treatments. For these data, the accumulation of d 2 h ) by individual trees over two years was efficiently represented by a six-parameter non-linear model of ln ( d 2 h ) as a function of time. Multivariate analysis of variance using these six estimated parameters for each seedling resulted in greater sensitivity to treatment differences as measured by tests of hypotheses than did analysis of covariance on ln (final d 2 h ). This result illustrates the importance of utilizing appropriate analyses that can bring as much of the data as is possible to bear on the question at hand. A test for additional information indicated that five of the six parameters contributed important information concerning treatment differences for at least one of the two families tested. It may be inferred that the treatments have an important effect on the nature of d 2 h accumulation within a growing season as well as on the d 2 h at the end of the growing season.

Using the 1988 and 1989 experimental results obtained for two loblolly pine half-sibling families (GAKR 15–23 and GAKR 15–91) at the Auburn University intensive field research site, we: (1) explored the performance of a set of exposure indices; (2) characterized the ambient air and charcoal-filtered air treatments at Auburn and compared the values of the O3 exposure indices with those values calculated for ambient O3 monitors for a select set of sites; (3) identified and characterized O3 treatments in the Auburn open-top exposure chambers where an adverse effect was noted; and (4) identified where such experimental exposure regimes occurred under ambient conditions. We found that the SUMO exposure index did not perform adequately. We were unable to distinguish among the performances of the SUM06, W126, and SUM08 exposure indices. The results of the analyses of six estimated logistic parameters for a model of diameter2 × height (d2h) vs time indicated O3 effects for both families. At pH 4.3 (near ambient conditions), a response to O3 was detected in the NF × 2.5 treatments for both families for t2, the approximate time of maximum growth during the second year. Using ln (final d2h), family 23 did not show O3 effects. A comparison of the exposures experienced in the NF × 2.5 treatments with those occurring under ambient conditions at other locations showed that in 1983 and 1986, the San Bernardino County (CA) site experienced O3 exposures similar to those values experienced at the NF × 2.5 treatments in 1989.

SUMMARY Loblolly pine (Pinus taeda L.) seedlings from two families differing in ozone sensitivity, were exposed to ozone and acidic precipitation in modified open-top chambers, beginning in May of 1988. Visible injury (bleached needle tips) occurred after a late-season frost in April, 1989 on newly emerging (length 5 cm) needles. After one week, needle tips turned brown and necrotic. Incidence of injury was recorded in April, May and June, 1989. Injury only occurred on trees exposed to ozone at above-ambient concentrations (1.7 and 2.5 × ambient), and was significantly greater in the ozone-sensitive family (GAKR 15-91) suggesting that this response is under some genetic control. Incidence of injury decreased with time and was more noticeable in the ozone-tolerant family (GAKR 15-23). There was no effect of acid rain, or interaction between ozone and acid rain, revealed by visible injury. In addition, experiments were conducted to determine if ozone and/or freezing temperatures enhanced electrolyte leakage. There were no differences observed in diffusate conductivity among treatments. These findings suggest that the observed injury was due to photo-oxidation induced by an ozone-low temperature interaction, and represent the first report of this type of injury in loblolly pine.

Natural communities dominated by longleaf pine (Pinus palustris Mill.) once covered an estimated two thirds of the forested area in the southeastern United States. Today, less than 1.2 million ha remain. However, over the past 10–15 years, public land managers have begun to restore many longleaf pine forests. More recently incentive programs have prompted reforestation and afforestation programs on nonindustrial private lands. These activities have been facilitated by improved longleaf regeneration technology and by expanded educational and outreach efforts. In the South, there is also a growing trend towards longer rotations due to changes in wood/fiber markets and prices. These trends suggest a new strategy to increase terrestrial carbon storage in the southeastern United States in a way that provides many simultaneous ecological and economic benefits. For example, longleaf pine is a long-lived species with a low mortality rate. Among the southern pine species, it has a high specific gravity and can tolerate a very wide variety of habitats. Longleaf pine is better able to sustain growth at older ages (over 150 years) and is tolerant to fire and many insects and diseases. Recent research also indicates that longleaf pine managed for longer rotations outperforms other commercial southern pine species on most sites and might better adapt to future climate scenarios with higher temperatures and higher atmospheric CO2 levels. Moreover, the higher-value, longer-lasting wood products derived from longleaf pine forests will continue to store carbon over long time periods.

Prior to the arrival of settlers to the United States, natural communities dominat by longleaf pine (Pinus palustris Mill.) and maintained by periodic fire occurre throughout most of the southern Atlantic and Gulf coastal plains. These com munities once covered an estimated twenty-four to thirty-six million hectare (h or two-thirds of the area in the Southeast (Vance, 1895; Chapman, 1932). Th range of longleaf pine covers a broad arc along the coastal plain and portions the Piedmont region from southern Virginia, south to central Florida, westward eastern Texas, and extends further inland in the Cumberland Plateau and Ridg and Valley physiographic provinces in Alabama and Georgia. Dissimilar to th other southern pines, longleaf pine tolerates a wide variety of habitats. It is foun growing on dry mountain slopes and ridges in Alabama and northwest Georgia, the low, wet flatwoods, as well as the excessively drained sandhills found alon the coast and fall line. Chapman (1 932) commented that longleaf pine covere more acreage than any other North American ecosystem dominated by a sing tree species.

Tannin and total phenolic levels in the foliage of loblolly pine (Pinus taeda L.) were examined in order to evaluate the effect of atmospheric pollution on secondary plant metabolism. The trees were exposed to four ozone concentrations and three levels of simulated acid rain. Tannin concentration (quantity per gram) and content (quantity per fascicle) were increased in foliage exposed to high concentrations of ozone in both ozone-sensitive and ozone-tolerant families. No effect of acid rain on tannins was observed. Neither total phenolic concentration nor content was significantly affected by any treatment, indicating that the ozone-related increase in foliar tannins was due to changes in allocation within the phenolic group rather than to increases in total phenolics. The change in allocation of resources in the production of secondary metabolites may have implications in herbivore defense, as well as for the overall energy balance of the plant.

A discounted cash flow model called the Impact Appraisal Model (IAM) computes the economic impact due to a change in timber production caused by a wildfire. Data requirements for the IAM can be obtained using standard inventory procedures to estimate the pre- and post-fire stand conditionsneeded to initiate a growth and yield simulator. The model is demonstrated using five loblolly plantations that burned in 1980 and 1981. South. J. Appl. For. 11(3):143-147.

Separate height and site index prediction equations were developed using stem analysis data from 168 dominant and codominant yellow-poplar (Linodendron tulipifera L.) trees felled at locations scattered across the hilly Coastal Plain in Alabama. South. J. Appl. For. 12(1):41-45.

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 (measured immediately following planting) was negatively related to survival, and the slope of the regression was four times greater when the planting chance was classified as poor than when it was classified as good. Initial height was also negatively related to 2-year height growth on poor planting chances, with shorter seedlings at planting reaching the same total height as taller ones after two seasons. As a result, initial field height on poor planting chances had little impact on total seedling height after two growing seasons. Therefore, there was no height growth advantage gained by planting seedlings taller than 20 cm when survival was less than 75%. Planting seedlings with heights of 20–34 cm was less of a problem when the planting chance was good. The use of shorter seedlings on planting chances where low survival may be expected may significantly increase loblolly pine seedling survival in the southern United States.

Height-over-age curves and site-index prediction tables were derived using nonlinear polymorphic regression models with data from 25-year-old old-field plantations ranging from coastal North Carolina to southwestern Arkansas. Plots from heavy silty clay soils of the interior flatwoods of Mississippi exhibited height growth patterns noticeably different from the overall pattern. A separate table and set of curves were developed for such sites.

Soil bulk density was related to loblolly pine (Pinustaeda L.) seedling establishment and growth during the first 28 weeks after sowing. Seedling heights were lower when bulk densities exceeded 1.3 Mg m−3 on a sandy clay loam and 1.4 Mg m−3 on a loamy sand. Heights were also lower for bulk densities below 1.2 Mg m−3 on the sandy clay loam soil. Seedling depth of rooting, root weight, and shoot weight were reduced at high bulk densities on both a sandy clay loam and a loamy sand. However, root and shoot weights were also reduced when bulk density fell below 1.3 Mg m−3 on the sandy clay loam. Bulk densities for best seedling growth were 1.3 Mg m−3 for the sandy clay loam and 1.4 Mg m−3 for the loamy sand.

Loblolly pine (Pinus taeda L.) seedling height (measured immediately following planting) was significantly related to survival after two growing seasons. This relationship was negative on sites classified as adverse, with shorter seedlings having better survival than taller ones. Onnonadverse sites, taller seedlings survived as well or better than shorter seedlings. On all sites, initial height was inversely related to total seedling height growth during the first two seasons, permitting shorter seedlings at planting to reach the same total height as taller ones by agetwo. As a result, at age two, initial field height was not significantly related to total height. South. J. Appl. For. 11(3):139-143.