Clifford E. Lewis

Species diversity and diversity profiles: concept, measurement, and application to timber and range management.

The concepts and use of several diversity assessments are presented and applied to a practical situation. Burning, mechanical methods of site preparation, and cattle grazing are common disturbances in forests of the South. Their influence on plant diversity indices are examined in a longleaf-slash pine forest of north Florida. Species richness, Shannons index, and Simpsons index showed increases in diversity shortly following burning and site preparation and a trend toward pre-treatment conditions after 6 years. Deferred-rotation grazing systems had no influence. Comparative diversity profiles showed similar trends but were more informative by providing both qualitative and quantitative information. These techniques are useful for assessing community responses to management practices, that is, they are effective methods for understanding the impacts of forest management and range management practices on plant community structure and succession.

Integration of pines, pastures, and cattle in south Georgia, USA

Native forages of southern United States are frequently low in nutrients and poorly digestible, while improved pastures are the opposite. Since this area produces rapid growth of pines, which is a major use of the land, the integration of pines, pastures, and cattle seem to offer an efficient and economical form of management. Therefore, in a 20-year study Coastal bermuda (Cynodon dactylon), dallis (Paspalum dilatatum), and Pensacola bahia (P. notatum) grasses were grown in pastures with no trees, and with slash pine (Pinus elliottii) spaced 3.7 x 3.7 and 6.1 x 6.1 m. The trees were grown free of competition for 3 years, grasses were established during the 4th year, and grazing by yearling cattle began the 5th year. The pastures were then fertilized, grazed, and burned for 15 years. Increasing tree canopies reduced forage production of all grasses. Bahiagrass was the most shade tolerant, while Coastal bermuda was the least. Liveweight gains during the 15 years of grazing totaled 3933, 2302, and 1518 kg/ha from pastures with no pines and slash pine spaced 6.1 x 6.1 and 3.7 x 3.7, respectively. Survival of slash pine was low due to heavy attacks by southern pine coneworm and southern fusiform rust. However, the trees grew rapidly and averaged 19.0 and 16.9 m in height, 30.0 and 33.3 cm in diameter, and 181.4 and 90.7 m3/ha of pulpwood after 20 years from the 3.7 x 3.7 and 6.1 x 6.1 spacings, respectively. Slash pine at these spacings planted in undisturbed, native vegetation were 16.0 and 15.7 m tall, 19.6 and 23.4 cm in diameter, and produced 145.5 and 63.6 m3/ha of pulpwood. Combining the production of pines and beef on improved pasture offers an opportunity for multiple-product yields. Since this approach to agroforestry is not trouble-free, good management is required. Landowners, especially those with small holdings, should consider these alternatives to single-product management when planning their cropping system.

Integration of pines and pastures for hay and grazing

When combining pine and cattle production on improved pastures, grazing may have to be delayed for several years until trees are large enough to resist injury. During this period forage would be lost unless harvested for hay. This study in south Georgia, USA, examined hay production during the first 3 years, cattle production during the next 3 years, and effects of this management system on survival and growth of slash pine(Pinus elliottii) planted in widely-spaced rows within the pastures.Pines were planted at 225 trees/ha in configurations of 3.0 x 14.6 or 4.9 x 9.1 m in pastures recently sprigged or seeded with Coastal bermudagrass (Cynodon dactylon) or Pensacola bahiagrass(Paspalum notatum). Pastures were fertilized annually and cut for hay four or five times each year.Wide-row spacings permitted haying operations, but tree rows and turning areas removed 5 to 8 percent of the area from production. However, hay yields and liveweight gains by yearling cattle were near normal for this locale.Slash pine planted in these fertilized pastures survived well, grew rapidly, and only a few trees were killed during haying operations. After 6 years, 83 percent of the trees survived and averaged 6.5 m in height and 13.2 cm in diameter. Cattle killed a few trees by rubbing during the 4th year.Wide-row spacing of pines permits harvesting forage for hay while waiting for the trees to become large enough to permit grazing. This approach to agroforestry produces annual returns to the landowner while awaiting maturity of the pines.

Herbage yield response to the maturation of a slash pine plantation.

Herbage yields in 8 newly planted slash pint (Pinus ellyonif Engehn.) plantation were measured annually for 26 years. Total herbage yield initially increased in response to removal of the previous forest canopy. Thereafter, yield decreased steadily as the canopy of the developing pine plantation closed until it leveled off rt about age 20. The maxima function described trends in yield for most spedes 8nd groups of tpecies. Accumte herbrge yield estim8tes over time don nun8gers of forested rangeland to plan crttle stocking r8tas or ur8nge for 8lternative sourcea of forage.

Simulated cattle injury to planted slash pine: defoliation.

Animals sometimes injure trees by eating the leaves. Little is known about the amount of removal required to harm survival and growth, particularly of southern pines. To simulate a single defoliation by livestock or wildlife, needles of slash pine were hand clipped once at 6, 18, and 30 months after planting. Survival and height growth were measured for six growing seasons after removing 0, 25, 50, 75, and 100% of the foliage. Survival was excellent except when 100% of the needles were removed 6 months after planting. Reductions in rate of height growth occurred only with the most severe levels of defoliation and were still apparent for 3 years after treatment. Even so, the greatest accumulated loss in height was less than 1 m over the 6-year period. Cattle and other animals sometime eat the foliage of trees, even resinous pine needles. However, Cassady et al. (1955) and Pearson (1976) observed that cattle rarely graze pine The author is principal range scientist, Southeastern Forest Experiment Station, Forest Service, U.S. Department of Agriculture, Marianna, Florida 32446. This was a cooperative study by the Georgia Coastal Plain Experiment Station, University of Georgia, College of Agriculture, Tifton, Ga., and the Forest Service, USDA. Acknowledgement is given to Dr. Karl F. Wenger, whose idea prompted the study, and to Ralph H. Hughes, who initiated the study. Manuscript received March 12, 1979. foliage when other green forage is available. The quantity of needles eaten varies with rate of cattle stocking, abundance and variety of other forage, season of grazing, seedling condition at time of planting, and seedling size. Various attempts to assess needle removal under actual grazing conditions have been too imprecise to evaluate or to predict subsequent tree performance. However, an understanding of defoliation impacts is necessary in devising plants for integrated management of forested ranges. This study evaluates the impact of simulated defoliation by cattle on survival and height growth of slash pine (Pinus eZZiottii Engelm.). Five degrees of seedling defoliation were simulated by hand clipping at three plantation ages.

Some herbage responses to fire on pine-wiregrass range.

Protecting two sites on pine-wiregrass range from fsire caused a rapid reduction in herbage yields. Reintroducing fire on these sites resulted in significantly increased yields, but removal of old growth by hand clipping instead of burning caused a decrease in yield on the site with Olustee sand and an increase in yield on the site with Plummer sand. Although gallberry cover did not recover as rapidly after burning on the Olustee site as on the Plummer site, covariance analysis indicated that these differences in recovery did not fully account for the disparity in yield between burned and clipped plots on the two sites.

Simulated cattle injury to planted slash pine : girdling.

Animals are known to girdle, or partially girdle, trees and shrubs by eating the bark or by knocking off the bark with their hooves. Since girdling has been observed in slash pine plantations being grazed by cattle, this form of injury was simulated on three ages of slash pine. Survival and growth were observed for 6 years after removal of a 5.1-cm-wide band of bark from around 50, 75, and 100% of the stem near groundline. Mortality was negligible except after complete girdling; even then, some seedlings lived. Height growth was reduced by the 75% girdle, primarily on seedlings treated within 6 months after planting. Two side tests on 100% girdles helped explain how trees can survive this severe injury. The cloven hooves of cattle, deer, and sheep can scrape off a portion of the bark from young trees. Also, mammals sometimes eat the bark from around the stems of trees and shrubs which results in high mortality. Although animals inflict various forms of damage to pines (Williston 1974), Wahlenberg et al. (1939) reported that damage to bark by cattle was rare. Wakeley (1935), Cassady et al. (1955), and Williston (1974) found that trampling injuries primarily occurred on young trees. Yet, Cassady et al. (1955) reported that injury by cattle caused no serious or permanent damage and concluded that slash pine (Pine elliottii Engelm.) and loblolly pine (Pinus taeda L.) have a remarkable capacity to recover. Information is lacking on how such injuries affect pine survival and growth. The study reported here was designed to measure the effects of simulated animal girdling on survival and growth of planted slash pine.

Planting slash pine in a dense pasture sod

Recommendations for planting pines usually include providing a competition-free site to assure establishment and good early growth. When combining pines and pasture in agroforestry systems, the possibility of planting pines directly into a pasture sod without site treatment would be economically desirable. In south Georgia, USA, slash pine (Pinus elliottii) was planted into a pasture sod and on well-disked sites; both with and without annual fertilization. Partial weed control was maintained in subsequent years on the cultivated treatments and the pasture sod was mowed periodically.Slash pine establishment and growth rate through 5 years generally was not different among treatments. Survival was 96% intially and 86% after 5 years. The pines grew rapidly with no measurable advantage from cultivation or fertilization.This alternative to providing a competition-free environment needs to be tested under differing climates, soils, tree species, and pasture species. It could be a suitable technique in various situations and of special interest to small, nonindustrial landowners.

Establishing Circular Plot Boundaries With a Wedge Prism and an Adjustable Target Pole

A target pole used with a walgc prism to establish a one-shccircular plot has been modified so tbat one target pole and prism an be llsed to establish the perimeter of circular plots of different sizes by a simple adjustment. Authors are forestry research technician and principal range scientist, Southeastern Forest Exp. Sta., Forest Serv., U.S. Dep. Agr., Marianna, Fla. 32446. Manuscript received June 16, 1980. JOURNAL OF RANGE MANAGEMENT 35(5). September 1992 If you use. circular plots of various sizes for sampling vegetation, you will be interested in a method that worked well for us. Establishing the perimeters of circular plots in shrubby or forested vegetation can be very time consuming because of the need to return to the plot center repeatedly to measure out to the perimeter, and sampling techniques sometimes require plots of increasingly larger size to be located around a central point in order to sample the various vegetation components such as herbage, shrubs, and trees.