September 6, 2008
Longleaf cone crop good in South Carolina this year
Longleaf pine trees will produce a good crop of cones this fall in much of South Carolina and across the species’ range, according to Rhett Johnson, forester, wildlife biologist, and co-founder of the Longleaf Alliance.
Bob Franklin, Clemson Extension forestry and wildlife specialist, said: "Longleaf pine does not produce as many cones nor seeds as regularly as other Southern pine trees, and so it is important for folks who seek to restore and manage longleaf through natural regeneration to be aware of predicted bountiful cone crops and take advantage of them."
Keep in mind that in a given forest not all longleaf pine trees will produce cones in any given year, and that not all forests produce lots of cones, even in years that are generally good for longleaf cone crops. Also, in years with poor cone crops some individual trees may produce cones. Longleaf pine forests generally produce good cone crops about once every five to 10 years.
Longleaf pine cones, like other Southern hard pines, require two years to mature, but unlike most other Southern pines, the seeds sprout in the fall. Sprouting in fall is likely an adaptation to help the tree begin developing a good root system before next spring’s competition starts, and also to avoid predators that might eat the seeds during the winter. Longleaf has what is called a hypogeal strategy, meaning that it puts much of its early growth into underground parts of the seedling, whereas pines like loblolly allocate more of their early growth aboveground (an epigeal strategy).
Longleaf requires more sun than other Southern pine trees, and also must have bare mineral soil to germinate well, and so it is vital to reduce competition from other plants, and to remove excessive amounts of needles and other organic materials from the forest floor before the cones open (while still on the tree) and the seeds fall to the ground. An ideal way to do this is with prescribed fire. Fire is not only an effective and relatively inexpensive way to conduct site preparation (site-prep) but it is the age-old and natural way.
Carefully conducted prescribed fires help reduce competition for sunlight and nutrients by killing or injuring fast-growing plant species like red maple and sweetgum, and fire also consumes pine needles and other leaves which would otherwise keep longleaf seeds from reaching mineral soil. If a site has been burned properly in the last year it most likely will not need to be burned again before seedfall, but if not, and especially if competition from other plants and lack of bare soil are evident, then a fire between now and the time when cones begin opening in late October is needed if natural longleaf regeneration is desired. While fire is often prescribed in September or early October to site-prep just before longleaf seedfall, a fire earlier in the year may be better in some instances because a bit of regrowth and litterfall may help hide the seeds from the many species of animals that eat them.
At least 750-1,000 cones per acre (30-75 cones per tree depending on tree density) are needed to successfully regenerate a site, and the site must be open enough to allow sufficient sunlight to reach the ground. In good cone crop years, longleaf generally produces an abundance of seeds, enough for regeneration as well as for animals to eat. On average, longleaf produces about 40-50 seed per cone. Most viable longleaf seeds fall within about 65 feet of the parent tree, but strong winds during seedfall can take the heavy, but winged seed a good bit farther. The seed germinate 2-6 weeks after falling from the cone.
Longleaf seeds are high in nutrients and are an important food source for bobwhite quail, doves, wintering sparrows, Carolina chickadees, nuthatches and other birds. Research shows that movement patterns of doves in some areas may be governed by the availability of longleaf seed. The seeds are also favored by rodents such as mice, rats, and squirrels— especially fox squirrels. While most animals eat longleaf seed only after they have hit the ground, the fox squirrel tears apart the large cones before they open. This habit is evident in the bracts that litter the ground beneath cone-bearing longleaf trees and also atop stumps on which the big squirrels sit and feed when cones fall or are cut from the tree before opening. The large size of the fox squirrel subspecies in the Southeastern U.S. may be a specific adaptation to tearing apart these large, tough cones. Fox squirrels in the Midwest and other parts of the species’ range, where longleaf does not grow, are much smaller. Southeastern fox squirrels may also have evolved their black and silver coloration to blend in with the burned and unburned trunks of trees in the longleaf pinelands, and thus help avoid predation.
Once naturally regenerated longleaf pine is established, it should not be burned until it has had at least one full growing season. But once it has grown into a robust seedling that resembles a clump of grass (longleaf’s characteristic "grass-stage") with a basal diameter of about one-third inch, it is very resilient to fire, and burning will help control competition from other woody species as well as encourage desirable herbaceous plants that are pretty, as well as good for wildlife cover and food.
A much less-well known fact about longleaf reproduction is that the just-sprouted seedlings are good to eat! Wayne Grooms, Lexington County conservationist and long-time volunteer on S.C. Department of Natural Resources and The Nature Conservancy projects, says that when the seedlings are very young they lack the characteristic pine resin taste that needles of older pines have, and are a good addition to salads. Grooms allows that in the past, during hard times in the "Piney Woods," folks took advantage of every local source of nutrients they could find. He remembers eating them in salads as a child and has continued to do so all his life. If you wish to try this tasty, natural food this fall, look for one-two inch high sprouts that resemble umbrellas with the fabric torn off, leaving only the handle (embryonic stem) and the five to 10 extended "arms" (these first whorls of leaves are called cotyledons, and feed the plant until it begins photosynthesizing) under mature pine trees that have recently-opened cones. But when you find them, don’t depend on coming back to get them in a few days, because doves and other animals also relish these succulent treats, and so by then they may be gone!
For more information on longleaf pine, contact Johnny Stowe with the S.C. Department of Natural Resources at (803) 419-9374 or e-mail StoweJ@dnr.sc.gov.
DNR protects and manages South Carolina's natural resources by making wise and balanced decisions for the benefit of the state's natural resources and its people.