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Native forages of the 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 × 3.7 and 6.1 × 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 1518kg/ha from pastures with no pines and slash pine spaced 6.1 × 6.1 and 3.7 × 3.7, respectively. Survival of slash pine was low due to heavy attacks by southern pine coneworm and southern fusfform 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 × 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 multipleproduct 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.

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The concepta 8nd m of sevcnl diversity 8ssessments 8re presented 8nd 8ppiied to 8 pnctierl situ8tion. Burning, mech8niul methods of site prepurtion, rad c8ttie pizing ire common dis-turb8nces in forest8 of the South. Their influence on pi8nt diversity indices ue exrmined in 8 iongle8f-si8sb pine forat of north Flor-id8. Species richness, Shnnon's index, md Simpson's index showed incrwes in diversity shortly following burning md site prepu8tion 8nd 8 trend towed pre-tre8tment conditions 8fter 6 ye8rs. Deferred-rot8tion gr8zing systems hrd no infkence. Cornpwtive diversity profiles showed simik trends but were more infonnrtive by providing both qaulit8tive md qu8ntit8tive informrtion. These technique8 8re us&11 for newsing community reaponeee to m8n8gement prrctic* th8t is, they 8re effective methods for underst8nding the imp8cts of forest nunrrgement 8nd nnge management pnctices on pleat community structure and succewion. Key Work species richness, Sh8nnon's diversity index, Simp son's diversity index, compurtive diversity profiies, phnt succession, pine-wiregrmss vegetrtion Literature on the mcasurcment of specks diversity is vohnninous. Many indices have been proposed, and there has been much debate concerning their use and meaning. Analogous measurements appear in ecology, genetics, linguistics, information theory, and economics. Fortunately, significant theoretical advances have recently appeared in the ecological literature (e.g. Grassle et al. 1979). Patil and Taillie (1982) proposed a compelling definition of species diversity and showed unified, intuitive motivations for the most popular indices along with their relatedness to measures of rarity. These authors and others (e.g. Solomon 1979, Taillie 1979) introduced concepts of intrinsic diversity orderings. When intrinsic orderings exist between 2 communities, any diversity index will agree with the indicated ordering, so these orderings are index free. Some forest and range management practices (especially clearcut harvesting with intensive site-preparation and range improvement through chopping or discing) conjure vivid images of ecosystem destruction. Hence, many conservation and environmental groups have suggested a need for assessment of the effects of such practices on species diversity. Therefore, we need better tools for assessing and presenting the impacts of management practices on community structure. Indeed, the National Forest Management Act of the United States [Federal Register 44(181), 219.13(6)] requires that managed practices maintain the diversity of forest ecosystems as demonstrated by quantitative comparisons of the diversities of natural and managed forests. The Act is based not only on aesthetic preferences, but on sound biological principles as well-for example, a diverse community represents a larger gene pool, and is less susceptible to devastation by catastrophic events such as pest epidemics. In this paper we analyze recent data from integrated pinegrazing management research to determine trends in species occurrence, cover, and...

Tifhi‐1 bahiagrass, Coastal bermudagrass, and prostrate dallisgrass were planted in 1962, under a stand of 5‐year‐old slash pines, spaced 3 m apart and averaging 5.2 m high. We applied N at 56, 112, 224, 336, and 448 kg/ha, and enough P and K to give a 2:1:1 ratio of N:P2O5:K2O. Grass yields were taken every 6 weeks. In 1963, all grasses responded to N; maximum yields of bahia‐, bermuda‐, and dallisgrass were produced at 224, 336, and 112 kg/ha of N, respectively. N response was the same in 1964, except that bermudagrass produced maximum yields at only 222 kg/ha. No N response was seen in 1965; bahia‐ outyielded bermuda‐ and dallisgrass. In 1966, there were no differences among grasses, and no N response. In 1963, grass yields under the trees were as high as yields in the open, but in 1964, when the trees intercepted 84% of the light, they were somewhat lower. In 1965 and 1966, grass yields under trees were much lower than yields in the open. Yield decreased linearly as tree basal area increased. Crude protein content and dry matter digestibility increased with increased N rates; differences among grasses were small. Grass yields were higher than native range yields previously reported, however, the range yields were taken under different conditions of shading and fertilization. Quality of native range herbage and the grasses in this study was about the same, but quality of the improved grasses was depressed by infrequent cutting.