• Decision-analysis approach to brush management planning: ramifications for integrated range resources management

      Scifres, C. J. (Society for Range Management, 1987-11-01)
      Simulation, optimization, and other modeling paradigms for systems ecology and economics have not been broadly applied to development of models for range resource management in real-world settings. The lag in emergence of applicable management models may be attributed to the lack of a conceptual context for their application. Recent appreciation of the decision-analysis approach to natural resource management and the general availability of high-speed computing capabilities have provided viable bases for using increasingly sophisticated analytical tools to solve management problems. Decision models may be used to generate proforma contrasts of selected management alternatives for multi-enterprise firms and implementation protocols for the selected management program(s). Such models, operating from a computer-managed information base, become decision-support systems (DSS) for approaching specific management problems; Integrated Brush Management Systems (IBMS) is one example. These DSS are proposed at the first step toward creating comprehensive decision-making models for total resource management (i.e. Integrated Range Resource Management or Integrated Range Resource Analysis). The next generation of models will link qualitative information and rules-of-thumb (heuristics) with hard (experimentally derived) data. These knowledge-based or expert systems, one facet of the growing field of artificial intelligence, hold great promise as vehicles for achieving Integrated Range Resource management. Bringing Integrated Range Resource Management Systems to fruition can be expedited by interdisciplinary research and educational programs for potential user groups.
    • Ecology and management of kermes oak (Quercus coccifera L.) shrublands in Greece: A review

      Tsiouvaras, C. N. (Society for Range Management, 1987-11-01)
      Kermes oak (Quercus coccifera L.) shrublands occupy more than 0.4 million ha in Greece and are the typical browse rangelands for 4.5 million goats. Five "range types" of kermes oak were identified based on morphological differences. Clipping of kermes oak improves growth rate of twig length, increases the production of new twigs, and alters the nutritive value of browse. Kermes oak can withstand very heavy (100%) clipping of twigs for 2 consecutive years, yielding the highest growth rate and twig number. Browse production varies among different forms of kermes oak shrublands. The low form (0.5-0.8 m height) yielded the highest production (3,467 kg ha-1). Goat liveweight gain of tall form (2 m height) of kermes oak shrubland was 25 kg ha-1 yr-1; improved shrublands, by topping, produced double liveweight gain when their form was altered. Liveweight gain was almost quadrupled when kermes oak shrublands were converted to grasslands.
    • Optimal economic timing of range improvement alternatives: southern High Plains

      Ethridge, D. E.; Pettit, R. D.; Sudderth, R. G.; Stoecker, A. L. (Society for Range Management, 1987-11-01)
      Profit maximizing combinations of livestock enterprises, plant control practices, and grazing management systems for ranches in the southern High Plains were examined. A typical ranch and a multi-period linear programming model were used to determine the combinations and timing of improvement practices and enterprises to maximize discounted net income with different investement capital constraints, cattle prices, and discount rates. All solutions included chemical control of sand shinnery oak (Quercus havardii) and a rotation grazing system. Timing of improvements and net income were affected by size of investment capital constraint.