• Season of cutting affects biomass production by coppicing browse species of the Brazilian caatinga

      Hardesty, L. H.; Box, T. W.; Malechek, J. C. (Society for Range Management, 1988-11-01)
      This paper reports the effect of season of cutting on coppice biomass production by 5 tree species common in the semiarid caatinga woodlands of northeast Brazil. Trees were cut early and late in the wet and dry seasons and coppice biomass production was monitored for 2 growing seasons after cutting. No mortality occurred as a result of cutting in any season. The effect of season of cutting on subsequent coppice production was most pronounced in the first year but differences persisted into the second year. Production by trees cut late in the wet season lagged behind that of trees cut at any other time. This was true for all species except marmeliero (Croton hemiargyreus Muell. Arg.) during both years. Pau branco (Auxemma oncocalyx Taub.) production was maximized by cutting late in the dry season. Jurema preta (Mimosa acutistipula Benth.) and catingueira (Caesalpinia pyramidalis Tul.) production was maximized by cutting early in the dry season. The season of cutting does not affect marmeliero stem production. Except for the late wet season, no treatment significantly affected sabiá Mimosa caesalpinifolia production. Stem biomass production is affected more by season of cut than is leaf biomass production. The different patterns of response among these species could be the basis of a selective cutting scheme to achieve objectives such as browse and wood production.
    • Species diversity and diversity profiles: concept, measurement, and application to timber and range management

      Lewis, C. E.; Swindel, B. F.; Tanner, G. W. (Society for Range Management, 1988-11-01)
      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, Shannon's index, and Simpson's 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.
    • Stability of African pastoral ecosystems: Alternate paradigms and implications for development

      Ellis, J. E.; Swift, D. M. (Society for Range Management, 1988-11-01)
      African pastoral ecosystems have been studied with the assumptions that these ecosystems are potentially stable (equilibrial) systems which become destabilized by overstocking and overgrazing. Development policy in these regions has focused on internal alterations of system structure, with the goals of restoring equilibrium and increasing productivity. Nine years of ecosystem-level research in northern Kenya presents a view of pastoral ecosystems that are non-equilibrial but persistent, with system dynamics affected more by abiotic than biotic controls. Development practices that fail to recognize these dynamics may result in increased deprivation and failure. Pastoral ecosystems may be better supported by development policies that build on and facilitate the traditional pastoral strategies rather than constrain them.
    • Stability of grazed patches on rough fescue grasslands

      Willms, W. D.; Dormaar, J. F.; Schaalje, G. B. (Society for Range Management, 1988-11-01)
      Continuous stocking usually leads to the formation of grazed patches. However, the effect of patches on the grassland community is related to their stability. Therefore, we studied the spatial stability of grazed patches on Rough Fescue Grasslands by mapping forage removal classes on 10 sites over a 4-year period, testing stability using the Kappa index (K), and characterizing the soils and vegetation of overgrazed and undergrazed patches. Spatial stability of grazed patches between consecutive years was good (K is greater than or equal to 0.26) on sites experiencing low grazing pressure. However, on sites having high grazing pressure, spatial stability was less consistent between consecutive years (0>K is lesser than or equal to 0.45) and low over a 4-year period (K is lesser than or equal to 0.10). Overgrazed patches were dominated by grazing-resistant seral species, but undergrazed patches were dominated by climax species. Rough fescue (Festuca scabrella) and Parry oat grass (Danthonia parryi) plants were 50% shorter, and forage production was about 35% less, on overgrazed than on undergrazed patches. Soil organic matter, carbohydrates, and depth of Ah horizon were significantly greater on undergrazed patches but urease activity, NO3-N, NH4, and available phosphorus were greater on overgrazed patches. Overgrazed and undergrazed patches were stable in the long term, although patch boundaries fluctuated.
    • Stocking rate effects on intensive-early stocked Flint Hills bluestem range

      Owensby, C. E.; Cochran, R.; Smith, E. F. (Society for Range Management, 1988-11-01)
    • Technical Notes: Separating leaves from browse for use in nutritional studies with herbivores

      Gallagher, J. F.; Barnes, T. G.; Varner, L. W. (Society for Range Management, 1988-11-01)
      A technique has been developed that facilitates removal of green leafy material from stems of shrub species using a thresher. Use of this technique makes possible the rapid removal of leaves from woody species that would otherwise require excessive hand labor.