Longleaf pine site suitability

April 2011 Leaflet orth Carolina Forest Service LL # 3 LONGLEAF PINE SITE SUITABILITY Longleaf pine grows on many different sites and soils within North Carolina’s coastal and piedmont regions. Seven distinct longleaf pine plant communities occur in the state: xeric sandhills scrubs, pine/scrub oak sandhill, mesic pine flatwoods, wet pine flatwoods, coastal fringe sandhills, pine savannahs and piedmont longleaf forests. These plant communities range in soil type and wetness class and have been maintained throughout history with frequent, low-intensity fire. Longleaf Evolved with Fire Fire plays an important role in shaping longleaf pine forests. Historically and ecologically, it is likely the single most significant influence on longleaf’s ability to grow on any particular site. Without fire, over time longleaf will give way to more competitive hardwoods or pines. Longleaf pine has developed unique characteristics that provide a competitive advantage over other less fire resistant species. Longleaf pine is resistant to low intensity fires due to the long needles that protect the terminal bud during the “grass stage”. After the grass stage, which usually last 2-to-5 years, the longleaf pine grows in height for another 3-to-5 years. During this early growth phase, the tree is more susceptible to damage and mortality from fire. As the tree grows tall and its bark thickens, longleaf pine once again becomes very tolerant of wood fire. Fire remains just as important as a management tool today as it was in the past to control woody competition, expose mineral soil for seed germination and maintain fire dependant understory plants. Longleaf Grows on Many Soils and Sites Longleaf pine is native to a wide variety of sites ranging from wet, poorly drained flatwoods to dry, rocky mountain ridges. Elevation ranges from barely above sea level in the lower Coastal Plain to 1800 feet above sea level in the mountains of Alabama. In North Carolina, most longleaf pine forests are found below 300 feet in elevation. Here the soils are largely derived from marine sediments and range from deep, coarse, excessively drained sands to poorly drained clays. The broad soil orders associated with longleaf pines include Entisols, (deep sandy soil found on dry Sandhills), Ultisols (a red- yellow soil, the most common in NC) and Spodosols (wet sandy coastal plain soils with a shallow water table at or near the surface in the winter). Clay layers found beneath the surface collect and hold rainwater that help longleaf survive on dry, excessively drained sandy soils. Longleaf pine is found most often in soils that are sandy on the surface, low in organic matter, light colored and are medium to strongly acid. Drainage is often good to excessive. In the Sandhills, the surface sands are yellow-gray, low in organic matter and fertility, strongly acid and underlain by loose yellow sands to a depth of 3-to-80 feet. Drainage is good to excessive. Along the coast, longleaf grows in the wet flatlands. Soils along the coast that have gray, mottled subsoil, indicating poor drainage and soil aeration, are unsuitable for longleaf. Longleaf soils can be seasonally wet but not saturated for a long time. Longleaf does not tolerate frequent flooding. Soil Properties and Suitability There are key soil properties that influence the establishment and growth of longleaf pine. These properties are summarized for each soil type in various tables in county Soil Surveys published by the USDA Natural Resources Conservation Service. They include infiltration, shrink-swell potential, bulk density, site index and ordination symbol. A soil series is a group of soils with similar profiles but differ in the texture of the surface layer Common Longleaf Pine Soils with Site Quality Index* Altavista - 85 Baymeade - 65 Blanton - 70 Bonneau - 75 Chipley - 80 Conetoe - 65 Craven - 67 Dunbar - 70 Exum - 77 Foreston - 75 Fripp - 60 Goldsboro - 77 Kenansville - 65 Kureb - 55 Lakeland - 70 Lenoir - 70 Leon - 70 Lynchburg - 74 Marlboro - 62 Norfolk - 68 Onslow - 67 Osier - 68 Pactolus - 70 Rimini - 55 Wag ram - 67 * Site Index is a measure of site/soil quality that represents the predicted tree height at age 50 This publication was made possible through funding from the American Recovery and Reinvestment Act. Page 1 of 2 LL-#3