Hardwood Plantation Forest Management

Plantation silviculture of bottomland species like cottonwood, sweetgum, and American sycamore has been successful, but plantations of upland hardwoods have had limited success.  Procedures have been developed for establishing hardwood plantations on alluvial floodplains (Malac and Herren 1979). Industrial foresters have focused on developing eastern cottonwood (Populus deltoides Bartr. ex Marsh.) and sycamore (Platanus occidentalis L.) plantations. Eastern cottonwood has shown more promise than other species in the Mississippi River Delta, but sycamore—and to some extent sweetgum, green ash, water oak, and willow oak—have proven more adaptable than cottonwood to some of the other alluvial floodplains of the South. About 125,000 acres of commercial hardwood plantations currently exist in southern bottomlands. Despite successes on the floodplains, with growth rates of 3 to 4 cords per acre per year at rotations of 15 to 18 years, the trend is to establish hardwood plantations outside of the alluvial floodplains. The causes for this shift in site location include environmental concerns and the difficulty of managing and harvesting the resource in areas with episodic flooding. Few industrial forestry organizations are willing to invest in plantation forestry in alluvial floodplains when there is significant uncertainty about the implications of the Clean Water Act for such operations. 

Floodplain forest restoration efforts have been limited, and most have focused on reestablishment of forest cover for timber, stream protection, or wildlife habitat values (King and Keeland 1999, Stanturf and others 1998). Typically forest managers have tended to increase the numbers of certain preferred tree species in the stands (Chambers and others 1987). In the past 10 to 15 years there has been a preference for planting oaks (Haynes and others 1995, King and Keeland 1999), and this practice could result in a greater occurrence of oak regionally than was typical of presettlement forests (The Nature Conservancy 1992). More recently, greater emphasis has been given to planting a wider variety of bottomland species (Allen and others 2001, King and Keeland 1999). 

Several of the largest reforestation efforts today are in areas of the Lower Mississippi River Valley, including parts of the Yazoo National Wildlife Refuge, the Tensas National Wildlife Refuge, and the Ouachita Wildlife Management Area, and on privately owned land enrolled in the Wetland Reserve Program. About 193,000 acres have been seeded or planted, with the potential of 494,000 acres being returned to forest by the year 2005 (King and Keeland 1999). Many of the areas being reforested are on poorly drained lands cleared for agricultural crops in the 1960s and 1970s and abandoned later because of substandard crop yields and limited accessibility. Reforestation and restoration efforts are proving successful in reestablishing bottomland hardwood species that may provide commercial timber and wildlife habitat (Clewell and Lea 1990, Haynes and Moore 1988). 

Various forest establishment techniques have been used, including direct seeding of oaks and planting of seedlings or cuttings of several bottomland species (Stanturf and others 1998a). Although direct seeding is about half the cost of planting seedlings (Bullard and others 1992), the technique is reliable only for oaks and, to a lesser degree, other large-seeded species such as pecan [Carya illinoensis (Wangenh,) K. Koch]. Smaller seeds are more susceptible to damage by heat and dry soil. Allen (1990), who compared 4- to 8-year-old stands in the Yazoo National Wildlife Refuge, concluded that planting of tree seedlings was more effective than direct seeding in establishing wildlife habitat quickly. He reported extensive drought-caused mortality of newly germinated seeds, even though there was effective invasion of light-seeded species, especially sweetgum, green ash, and American elm.

The area of hardwood plantations is very small. It is estimated that there are about 200,000 acres of hardwood plantations in the South (Dvorak and Hodge 1998). Forest Industry owns about 60,000 acres of hardwood plantation. AF&PA southern forest management intensity survey.  In addition, the industry established about 12,000 acres of hardwood plantations with short rotation intensive silviculture (SRIS). These plantations are managed on up to 12-year rotations. Management treatments include intensive site preparation, plantation of genetically advanced seedlings, complete competing vegetation control, and high-intensity fertilization. Genetic improvement increases yields by up to 25 percent per rotation.

Hardwood plantation establishment in many cases has been difficult and expensive. Earlier plantations had growth rates similar to natural hardwood stands, with the exception of cottonwood plantations along the Mississippi River (Robison and others 1999). Progress in genetic improvement, propagation, and silviculture appears critical for hardwood plantations to increase the production of high-quality and uniform wood. Hybrid poplar plantations in the South already can grow substantially more timber than natural hardwood stands (Alig and others 2000).