Andrew W. Ezell

AFFORESTATION OF BOTTOMLAND HARDWOODS IN THE LOWER MISSISSIPPI ALLUVIAL VALLEY: STATUS AND TRENDS

The Lower Mississippi Alluvial Valley (LMAV) originally supported at least 10 million ha of bottomland hardwood (BLH) forests. Many of these forests were wetlands and provided a diversity of values that were not recognized fully until at least one-half of the original forested area had been converted primarily to row-crop agriculture. Efforts to restore these forests have expanded in proportion to growing recognition of their unique values. This paper provides a summary resulting from a survey of BLH afforestation by all agencies and private entities in Arkansas, Louisiana, and Mississippi, the three states in the LMAV with the most restoration activity and, more specifically, by the U.S. Fish and Wildlife Service, the U.S.D.A. Natural Resources Conservation Service, and state wildlife management agencies, the three entities responsible for approximately 95% of the afforestation in this region. There is a promising trend in the annual increase of BLH afforestation across the LMAV. Approximately 71,000 ha have been planted with BLH species through 1998; however, this represents <1% of the BLH forests that have been lost, and afforestation does not ensure restoration of all ecological functions. No clear choice between planting stocks (bareroot seedlings or direct seeding) or among planting seasons (Fall, Winter, Spring, or Summer) is prevalent among those involved in BLH afforestation. Much of the early afforestation used oaks (Quercus spp.) to accelerate replacement of mast-bearing species. Recently, mixtures of species have been incorporated into afforestation regimes. More light-seeded species and a more diverse component of oak species have been planted to mimic a more natural regeneration process. Successful widescale afforestation is a critical link in restoration of functional BLH ecosystems in this region.

Recognizing and Overcoming Difficult Site Conditions for Afforestation of Bottomland Hardwoods

SEPTEMBER 2004 183 In the last decade, about 370,000 acres (150,000 ha) of economically marginal farmland in the Lower Mississippi Alluvial Valley (LMAV) have been restored to bottomland hardwood forests (Stanturf and others 1998, King and Keeland 1999, Schoenholtz and others 2001). Planting of this considerable acreage is due to several federal programs, such as the Wetlands Reserve Program (WRP), that assist landowners by financing afforestation (Figure 1). Unfortunately, these operational plantings have not performed as well as smaller plantings or research plots (Stanturf and others 2001a). For example, a recent survey of WRP plantings in westcentral Mississippi revealed that more than 90 percent of the sites failed to meet the criteria of 100 woody stems per acre (247 stems per ha) three years after planting or direct seeding. While planting 1-0 bareroot seedlings of oak was more successful than direct-seeding acorns, only 23 percent of the land planted with seedlings met the criteria (C.J. Schweitzer unpublished data). Planting and direct seeding oak (Quercus spp.) on public land in the same area has been more successful. Meanwhile, Allen (1990) found 70 percent of the planted bottomland hardwood stands on the national wildlife refuges he evaluated had more than 200 trees per acre (494 stems per ha). We believe that the recurring problems in operational plantings on private lands are due in part to the failure of planters to recognize adverse site conditions and their failure to use appropriate methods for overcoming site limitations. Our objectives in this paper are to synthesize research and experience into guidelines for recognizing adverse site conditions due to hydroperiod, soil, competing vegetation, and herbivory. We describe techniques for overcoming these conditions and suggest promising research areas.

Nutrient dynamics in the lower Mississippi River floodplain: Comparing present and historic hydrologic conditions

Alterations to the lower Mississippi River-floodplain ecosystem to facilitate commercial navigation and to reduce flooding of agricultural lands and communities in the historic floodplain have changed the hydrologic regime. As a result, the flood pulse usually has a lower water level, is of shorter duration, has colder water temperatures, and a smaller area of floodplain is inundated. Using average hydrologic conditions and water temperatures, we used established nitrogen and phosphorus processes in soils, an aquatic ecosystem model, and fish bioenergetic models to provide approximations of nitrogen and phosphorus flux in Mississippi River flood waters for the present conditions of a 2-month (mid-March to mid-May) flood pulse and for a 3-month (mid-March to mid-June), historic flood pulse. We estimated that the soils and aquatic biota can remove or sequester 542 and 976 kg nitrogen ha−1 during the present and historic hydrologic conditions, respectively. Phosphorus, on the other hand, will be added to the water largely as a result of anaerobic soil conditions but moderated by biological uptake by aquatic biota during both present and historic hydrologic conditions. The floodplain and associated water bodies may provide an important management opportunity for reducing downstream transport of nitrogen in Mississippi River waters.

Two-year development of southern pine seedlings and associated vegetation following spray-and-burn site preparation with imazapyr alone or in mixture with other herbicides

Eight herbicide combinations containing imazapyr alone or in mixture with glyphosate, triclopyr, or picloram+2,4-D were applied July–August 1991 at each of three upland sites in the southeastern U.S., with or without a subsequent broadcast burn in September. Seedlings of loblolly (Pinus taeda L.) or slash (P. elliottii Engelm. var. elliottii) pine were planted that winter. Second-year (August 1993) vegetation responses indicate that broadcast burning, in combination with herbicides, was associated with increased abundances of grasses, forbs, and shrubs and decreased abundances of vines and hardwood trees. In the presence of burning, imazapyr-in-mixture treatments were associated with a high abundance of grass (53% cover) and a mean size of pines less than that of seedlings growing in imazapyr-alone treatments. In the absence of burning, imazapyr-alone treatments were associated with a high abundance of blackberry (21% cover), an average height of hardwoods (131 cm) exceeding that of pines (71 cm), and a mean size of pines less than that of trees growing in imazapyr-in-mixture treatments. Hardwood height in the absence of burning was less when imazapyr was combined with glyphosate (75 cm) than with triclopyr (102 cm). Regardless of the presence or absence of burning, size of pines and abundance of shrubs and hardwoods did not differ between imazapyr rates of 0.56 and 0.84 kg acid equivalent/ha or among herbicides applied in mixture with imazapyr.

Survival of Planted Oak Seedlings is Improved by Herbaceous Weed Control

Sulfometuron was applied at 0.1, 0.15, and 0.2 kg ai/ha over the top of oak seedlings. Three separate field studies were completed. In 1997, 0.1 and 0.2 kg ai/ha was applied PRE over six oak species. In 1998 and 1999, 0.1 and 0.15 kg ai/ha were applied PRE and 0.1 kg ai/ha was applied POST over two species of oaks. Results demonstrate that first-year survival of oak seedlings is greater in areas which receive competition control. Survival was 21 to 44% greater in treated areas as compared to nontreated areas. Observations indicate that survival differences are increased in droughty years. Competition control appears essential to obtaining desirable levels of survival when oak seedlings are planted in areas with established herbaceous competition. Nomenclature: Sulfometuron, oak, Quercus spp

Kudzu Control and Impact on Monetary Returns to Non-Industrial Private Forest Landowners in Mississippi

Kudzu—Pueraria montana var. lobata (Willd.)—was initially planted in the southern United States and subsequently spread throughout the countryside following changes in land use. Kudzu covers more than 2.8 million ha which prevents uses such as timber production and establishment of carbon plantations. Using data collected on sites in Mississippi, this study examines the after-tax monetary trade-offs of controlling kudzu using different herbicide regimes. The results suggest that the most cost-effective way to control kudzu patches is to apply Escort XP using an aerial applicator. This application is appropriate for both young and old kudzu patches and whether the landowner intends to afforest the site with pine or oak.

Growth Response of Loblolly Pine (Pinus taeda L.) 3–5 Years After Plantation Establishment Using Different Management Intensities

The upward trend of intensive management in Southern pine forests is expected to continue, both in area and intensity level. Much of the Mississippi Lower Coastal Plain (LCP) is managed intensively using some combination of mechanical site preparation, chemical site preparation, and herbaceous weed control (HWC). We studied pine growth response and competition control on loblolly pine (Pinus taeda L.) plantations 3–5 years following establishment using five combinations of chemical site preparation, mechanical site preparation, and HWC. Treatments were designated a priori as 1 (least intensive) through 5 (most intensive) largely on the basis of anticipated impact on the vegetation community. We measured pine height and diameter at breast height (dbh); woody stem density; hardwood basal area (BA); coverage of herbaceous plants, understory woody plants, and pine trees; and estimated differences in pine response using age-shift calculations at age 5. Pine height and dbh were correlated with treatment intensity; treatment 5 maintained an average advantage of 1.4-m height and 2.5-cm dbh over treatment 2, the least responsive treatment. Woody stem density varied widely and was not affected by treatment; understory woody coverage was also unaffected by treatment. Coverage of herbaceous plants was reduced in treatments receiving broadcast HWC, and in treatment 2, where slower establishment of pines may have acted as a release for competing woody plants. Age-shift gains relative to treatment 2 ranged from 0.4–1.0 years. Based on year 5 measurements of hardwood BA, it is likely that treatments 1 and 2 will fall further behind treatments 3–5 as the stands mature. Greatest control of competing vegetation and maximum growth of pines was achieved with the most intensive treatment.

Impacts of Southern oak seedling survival on investment returns in Mississippi

Abstract Increasingly, landowners are establishing hardwood plantations to satisfy their land management goals. Unfortunately, little is known about how competition control affects initial seedling survival and subsequent investment returns for hardwood plantations. This study examines five alternative competition control regimes for southern oak establishment. The regimes include no site preparation, disking only, sub-soiling with rotary mowing, herbicides only, and herbicides with rotary mowing and sub-soiling. The analysis includes both before— and after-tax estimates of land expectation value (LEV) for comparing alternatives. Our results suggest that greater returns can be achieved for southern oak plantations in Mississippi during both good and bad rainfall years using herbicides only or herbicides with rotary mowing and sub-soiling for competition control. Applying intensive competition control during the first year yields after-tax LEVs of

Weed Control and Crop Tolerance after Preemergent and Postemergent Applications of Sulfometuron in Oak (Quercus spp.) Plantations1

577.64 to

Carbon allocation and morphology of cherrybark oak seedlings and sprouts under three light regimes

691.66 per hectare despite precipitation levels. Not applying competition control yields after-tax LEVs from