Thesis (M.S.)--Virginia Polytechnic Institute, 1962. / Vita. Abstract. Includes bibliographical references (leaves 121-124). Also available via the Internet.

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Browse biomass production of Salix spp. and Betula glandulosa on a wetland in central British Columbia is estimated. Based on an extensive review of much of the literature pertaining to shrub biomass and shrub density estimation, a technique combining regression estimates of average stem biomass with a density estimate obtained using the corrected point distance method was applied. It was found that the best regression relationships were obtained using natural logarithmic transformations of the dimension and biomass variables. It was possible to obtain acceptable biomass equations for the four Salix species encountered without differentiating between the species. More accurate predictions of biomass were achieved using site specific equations and equations based on pooled site data than with general equations. It was concluded that the value of the approach taken is limited if site specific equations are required because of the considerable time required for sample collection and preparation. / Forestry, Faculty of / Graduate

This study is one phase of a ten-year project designed to evaluate forest-wildlife relationships. The project was initiated in 1958 on the Jefferson National Forest, Broad Run Wildlife Management Area, Craig County, Virginia. The objective of the study was to determine if correlations existed between quantities of available deer browse in the understory of a particular forest cover type and several site quality measurements. The purpose of the study was to determine if weights of browse per acre could be estimated reliably by utilizing easily obtained site quality measurements instead of clipping and weighing browse. Eight site quality measurements (variables) were tested. These were: site index, depth of the A₁ soil horizon, position on slope, basal area per acre, aspect (exposure), percent of slope, elevation, and the number of clipped stems per sampling unit. Fieldwork was conducted in two major forest cover types; the oak, hickory, poplar, white pine type (cove hardwoods type), and the mixed oak-pine type. Sampling units were located randomly, in pairs, within each of these two forest cover types. Each sampling unit consisted of a circular 1/4 acre plot and a square 1/100 acre plot located at the center of the circular plot. A system of double sampling was used to obtain browse weight data and site quality data for comparisons. Data on eight variables recorded at each 1/4 acre sampling unit were compared with the quantity of browse clipped from the 1/100 acre sampling unit located at the center of that particular 1/4 acre plot. A multiple regression analysis was used to determine the degree of correlation between quantities of browse (available browse) clipped from sampling units and all measurements of the eight independent variables (site quality measurements) recorded on sampling units. The final analysis of the oak, hickory, poplar, white pine cover type data indicated that the variables significantly related to browsing weights per acre were the number of stems clipped per sampling unit and the depth of the A₁ soil horizon. These two significant variables explained 48,63 percent of the total variation in browse weights occurring between sampling units. Using only the two significant site quality measurements (independent variables), the final estimating equation was: Y (pounds of browse per acre) = -0.14 + 0.06 (number of stems clipped per sampling unit) + 0.61 (depth of the A₁ horizon, inches). The final estimating equation should not be used for reliable estimates of browse production in the oak, hickory, poplar, white pine forest cover type. A total of 51.37 percent of the variation in browse weights occurring between sampling units is unaccounted for in this equation. The final analysis of the mixed oak-pine cover type data indicated that the only variable significantly related to browsing weights per acre was the number of stems clipped per sampling unit. However, this significant variable explained only 17.97 percent of the total variation in browse weights occurring between sampling units. Using only the one significant site quality measurement (independent variable), the final estimating equation was: Y (pounds of browse per acre) = 2.24 + 0.07 (number of stems clipped per sampling unit). The final estimating equation should not be used for reliable estimates of available browse production in the mixed oak-pine forest cover type. A total of 82.03 percent of the variation in browse weights occurring between sampling units was unexplained in this equation. More research is necessary to determine other easily measured environmental factors (variables) which might bear a significant relationship to quantities of available deer browse produced in the two forest cover types sampled. When several more of these significant variables are discovered, the addition of these variables to the estimating equations for the two cover types might account for a large enough percent of the explained variation to enable the game biologist to use the equations for reliable estimates of browse production. / Master of Science

The purposes of this investigation which was conducted from September 1954 through October 1955, were (1) to determine the differences in available nutrients in selected deer browse species growing on different soils, (2) to investigate the variations in available soil nutrients as they may relate to chemical composition of selected deer browse species, and (3) to determine the variations in available nutrients in the selected browse species during different seasons of the year. The current year’s growth of twigs from flowering dogwood (Cornus florida), black locust (Robina pseudoacacia), and red maple (Acer rubrum) were collected at two-month intervals on study areas whose soils had arisen from either Brallier, Clinton, Huntersville chert, or Martinsburg shale geological formations. A proximate analysis was run on each browse collection. In addition to the above three species, rhododendron (Rhododendron maximum) and buffalo nut (Pyrularia pubera) were collected from the Brallier study area and analyzed. One-third of the samples of dogwood, locust, and maple that were collected after leaf fall in October 1955, were analyzed for calcium, phosphorus, cobalt, and manganese. Soil samples were collected on each area and analyzed by a flame spectrophotometer, LeMotte Soil Testing Outfit, and a rapid method. The soil which arose from the Brallier study area was lowest in value for phosphorous and second highest in values for total exchangeable cations and organic matter. The Clinton study area values were second highest in pH, phosphorous, and base saturation, and was highest in organic matter and manganese content. The chert values were the next lowest for phosphorus and lowest for pH, calcium, total exchangeable cations, and base saturation. The shale study area soil gave the highest values for pH, calcium, phosphorous, base saturation, and total exchangeable cations although it was lowest in organic matter. Of the three browse species collected from all the study areas, dogwood was generally high in moisture content, ether extract, ash, and nitrogen-free extract while being average in protein and low in crude fiber. Locust was high in protein and crude fiber and low in moisture, ether extract, and nitrogen-free extract. Maple was generally high in ether extract, crude fiber, and nitrogen-free extract and low in protein and ash. Rhododendron and buffalo nut were collected from the Brallier study area only. In comparison with the other three species on that area, rhododendron was very high in moisture and nitrogen-free extract; average to low in protein, ether extract, and crude fiber; average to high in ash. Buffalo nut was very high in moisture, protein, and ash; average in ether extract and crude fiber; and low in nitrogen-free extract. Seasonal trends in nutrient values for three browse species collected in all areas were observed. Protein content rose generally during the dormant months. Moisture content decreased from June through December and was followed by a rise that lasted until June. There was a rise in ether extract from September through June whereas the level of ash content was erratic during this period. Crude fiber was fairly stable in red maple and black locust although erratic in dogwood. There was a decrease in the nitrogen-free extract during the winter. Trends and consistencies in the nutritive values of the three species collected on all study areas, based on the study area on which they occur, are generally in the order of being high or low for one or two individual species rather than for all the species, or else they are considerably erratic. The different species have different nutritive values when growing on the same soil. During April and August, the different soils have their greatest effect on the nutritive values of plants; moisture content is greatly affected by the soil, and protein content is only slightly less affected. Except for the months of February and August, at least three of the six nutritive qualities of the plants were affected by the interaction between the plant and the soil. Analyses for minor elements reveal that black locust had the highest phosphorous and cobalt content; dogwood had the highest calcium content; red maple had the highest manganese content. On three of the four study areas, the manganese content of red maple exceeded the toxic level for bovines. On the chert area, dogwood and red maple were deficient, by bovine standards, in cobalt. / Ph. D.

no abstract provided by author / Master of Science

Thesis (MTech. degree in Nature Conservation.)--Tshwane University of Technology, 2010. / To a varying degree and for a variety of reasons black rhino require large areas of land but increasingly they are moved to smaller properties. Specific spatial and temporal problems are foreseen when keeping black rhino on small properties. The temporal problems under investigation on the Mokopane Biodiversity Conservation Centre where two black rhino are kept on 700 ha are: browse availability, browse utilisation as well as browse quality.

Browse selection, intake, utilisation, palatability, quality and production are tightly linked and need to be considered together in trying to improve our understanding of browsing dynamics and the interactions between browsers and vegetation. Such an understanding is necessary in order to re-evaluate determinations of browser carrying capacities and evaluating actual and potential impacts of browsing animals on vegetation composition and diversity. Browser carrying capacity is determined by both the quantity and the nutritive value of forage. The measurement of browse quantity and nutritive value and the matching of browse supply to browser demand are central to sustainable utilisation and the monitoring of vegetation health. South African savannas are poorly studied with respect to tree canopy growth and browse production making it difficult to quantify the available browse biomass on which browsing capacity estimations are based, and consequently difficult to estimate levels of browsing that are sustainable. This study addressed these issues by investigating browse dynamics, broadly aiming to (1) explore factors affecting browse production, biomass and nutritive value; (2) develop models to assess and monitor these parameters across seasons and properties; (3) use the resultant models in improving our understanding of how to determine browser carrying capacities. More specifically, our study sought to examine the effects of plant physiognomy, forage nutritive value, canopy stratum, defoliation, temperature, rainfall and soil nutrient status on the browse production of evergreen (Carissa bispinosa, Euclea divinorum, Gymnosporia senegalensis), semi-deciduous (Spirostachys africana, Ziziphus mucronata) and deciduous (Acacia nilotica, Dichrostachys cinerea) savanna tree species from June 2003 – June 2005 in three sites along the northern Zululand coastline of KwaZulu-Natal. Available browse biomass, during the dry season, of four key savanna tree species (A. nilotica, E. divinorum, G. senegalensis, and S. africana) was estimated through the development of allometric regression equations. Non-linear regression was used to investigate the relation between the leaf dry mass (LDM) and canopy volume (CVol) of each of the four tree species. Exponential regression (y = a + brlnx) of the natural logarithm of CVol data provided the most accurate and precise description of the tree CVol – LDM relation. A study was undertaken to determine which factors may influence browse production in a southern African savanna. Regression tree models for the browse production identified that the dominant factors influencing browse production were CVol (m3), season, species and height to the lowest leaves of the tree canopy (HL) (m). The length of the growing season had a marked effect on the production potential of savanna tree species, suggesting that improved conditions for growth, i.e. greater rainfall, soil moisture content and improved soil nutrient availability result in a longer period of rapid sustained growth. Species was identified as an important contributing factor to differences in browse production rates, suggesting the need for the development of species or species group models. Mean annual browse production of evergreen trees was greater than that of deciduous and semi-deciduous trees. Mean quarterly (three monthly) browse production was highest, for all trees, during the wet season, with the greatest difference between wet and dry season production being observed in deciduous forms. Evergreen forms showed continuous growth over the whole study, with enhanced growth over the wet season. Deciduous forms, on the other hand, concentrated growth in spurts, when environmental conditions became favourable, with most production occurring during a short growing season. Browse nutritive value was found to be greatest during the wet season, when growth and photosynthesis are at their greatest. Further, browse nutritive value was greatest in deciduous species. Evergreen trees were found to have greater acid detergent fibre (ADF) concentrations than both the deciduous and semi-deciduous trees. By contrast, crude protein (CP) concentrations were greater in semi-deciduous and deciduous species than in evergreen species. The daily CP requirements for maintenance for an adult impala (45 kg) were met by all species over all three study areas and all seasons. Daily CP requirements for growth and lactation, however, were only ever met by deciduous and semi-deciduous species, though this result was not consistent over study areas and seasons. Predictive models for the production of browse on deciduous, semi-deciduous and evergreen trees in northern Zululand were developed using multivariate adaptive regression spline functions. The best predictors of growing season browse production in all three tree guilds (defined here as a group of trees having a characteristic mode of living) were primarily measurable tree dimensions, while the prevailing environmental conditions had little impact. Differences in the production, nutritive value and available browse biomass between the different tree forms and seasons have a profound effect on the determination of browser carrying capacities and need to be incorporated into any game or conservation management plan. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.