Restoring an Ecosystem with Silvopasture: A Short(leaf) Story

Shortleaf pine (Pinus echinata) and native shortleaf ecosystems have been disappearing across its range at an alarming rate; approximately 50% loss of this forest type since the 1980’s (Oswalt 2011). An important part of the historic forest landscape in the United States, this species had the widest range of any southern-yellow pine; occurring in 22 states from Long Island, New York; west to southern Illinois and Missouri; south to northern Florida; and west to eastern Oklahoma and northeast Texas. Adaptation to fire was a major reason for the existence of shortleaf pine on a wide range of landscapes prior to European settlement (Mann 2002).

Shortleaf pine is one of the few pines that will sprout from a J-shaped crook at its base following top-kill (Garren 1943, Moser et al. 2007). This trait is thought to be an adaptation to frequent low-intensity surface fires with which shortleaf pine ecosystems evolved (Schwilk and Ackerly 2001). Today, the few remaining shortleaf forests primarily have large diameter trees with limited to no regeneration in the understory (Oswalt 2011), jeopardizing the future of these forests. This has been attributed to the prevalence of littleleaf disease (Phytophtora cinnamoni), extensive logging, the rapid growth of loblolly pine (Pinus taeda), and lack of fire (Campbell et al. 1953, Moser et al. 2007).

With littleleaf disease a concern, and the advent of mid-20th century industrial forestry, shortleaf pine regeneration efforts did not improve. Fire was removed from the landscape. Conversions from shortleaf stands to loblolly pine plantations were made based on shorter rotations and yield characteristics of loblolly pine (Williston and Balmer 1980). By 2010, only 6.1 million acres of shortleaf pine were estimated to remain, with the greatest declines noted east of the Mississippi River (Oswalt 2011). Loss of this ecosystem has not gone unnoticed in recent years. With the launch of the Shortleaf Pine Initiative in 2013, restoration efforts are gaining momentum (Shortleaf Pine Initiative 2015). Although Alabama landowners have often dismissed shortleaf pine as a viable component of management options due to concerns about littleleaf disease, Alabama is now at the forefront of this movement to prevent the loss of this imperiled system.

Across north and central Alabama, loblolly pine has long been favored by landowners for its rapid early growth and high market value. However, markets and interests are changing. Private landowners are looking for diversification in their forests; managing for value and not volume (National Woodland Owner Survey 2015). Land investments, scenic beauty, and recreation are often listed as reasons for ownership. Alabama landowners are also adopting agroforestry practices of silvopasture (managing livestock, forage and trees on the same area) and alley cropping (interspersing crops within rows of trees) (USDA 2012) and are requesting more agroforestry demonstration sites. Silvopasture in southern forests is not a new idea. In his book “Longleaf Pine”, W.G. Wahlenberg (1946) states, “In accordance with age-old custom, southern landowners usually tolerate grazing on their forest lands by the livestock of numerous small famers” (p. 309). During the past decade, there has been an accumulation of evidence that supports the ecosystem services and environmental benefits of science-based agroforestry practices including conservation of biological diversity, habitat creation, and erosion control (Jose 2009).

In an effort to address some of the misconceptions relating to shortleaf pine restoration, and increase the number of silvopasture demonstrations in Alabama, we established shortleaf and loblolly silvopasture demonstration sites at Redstone Arsenal (RSA) in Huntsville, Alabama. Redstone Arsenal is an approximately 15,380 ha U.S. Army installation that is committed to sustainable land management practices including forest management and wildlife habitat enhancement, making this project a natural fit with its goals and objectives.

In the February of 2010, RSA land managers machine planted shortleaf and loblolly seedlings on approximately 48 ha of inactive RSA agricultural leases. We selected sites based on soil suitability to reduce future susceptibility to littleleaf disease, and site prepped with a prescribed burn in January 2010 (Guthrie 2012). Approximately 24 ha were divided into 9 silvopasture blocks: 5 in loblolly and 4 in...