The relationship between size and density of Acacia Mellifera in the Highland Savanna of Namibia and its influence on the grass species composition and soil nutrients
Loading...
Date
2011
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Abstract provided by author
The Size-density relationship may be a valuable tool to reveal the extent of competition and mechanisms for distribution patterns, structure and functioning of woody species in savanna vegetation types. A study on the relationship between size and density of Acacia mellifera in the highland savanna of Namibia was carried out to try to facilitate an understanding of the development of stand density in relation to size (height) of A. mellifera. Data was collected at Neudamm farm in three camps that are inhabited by pure stands of A. mellifera. A total of ten clumps in each camp were selected, and the following recordings were made: Height (size) of the selected reference tree within the clump, crown diameter and crown form, and the distance to its two nearest neighbors. Another approach to data collection was the use of the nearest neighbor method, where every A. mellifera at every fifth point along a transect line was selected, its height, distance to nearest neighbor as well as the height of the neighbor were recorded. The results were analyzed with a linear model test to investigate the size-density relationship
The result from the test indicated that there is no significant relationship (P0.05) between the two. Significant relationship (P0.05) could only be found between crown diameter and height as well as between crown form and height. The influence of A. mellifera clumps on grass species composition and soil nutrients was also investigated, and there was a significant (P0.05) difference between grass species composition under and outside canopies
The study concluded that tree density does not affect tree size in A. mellifera species in the highland savanna of Namibia; hence no evidence of competition or self-thinning in A. mellifera stands yet. Therefore, competition may not the sole determinant of distribution and structure of wood species in savannas
The Size-density relationship may be a valuable tool to reveal the extent of competition and mechanisms for distribution patterns, structure and functioning of woody species in savanna vegetation types. A study on the relationship between size and density of Acacia mellifera in the highland savanna of Namibia was carried out to try to facilitate an understanding of the development of stand density in relation to size (height) of A. mellifera. Data was collected at Neudamm farm in three camps that are inhabited by pure stands of A. mellifera. A total of ten clumps in each camp were selected, and the following recordings were made: Height (size) of the selected reference tree within the clump, crown diameter and crown form, and the distance to its two nearest neighbors. Another approach to data collection was the use of the nearest neighbor method, where every A. mellifera at every fifth point along a transect line was selected, its height, distance to nearest neighbor as well as the height of the neighbor were recorded. The results were analyzed with a linear model test to investigate the size-density relationship
The result from the test indicated that there is no significant relationship (P0.05) between the two. Significant relationship (P0.05) could only be found between crown diameter and height as well as between crown form and height. The influence of A. mellifera clumps on grass species composition and soil nutrients was also investigated, and there was a significant (P0.05) difference between grass species composition under and outside canopies
The study concluded that tree density does not affect tree size in A. mellifera species in the highland savanna of Namibia; hence no evidence of competition or self-thinning in A. mellifera stands yet. Therefore, competition may not the sole determinant of distribution and structure of wood species in savannas
Description
A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science
Keywords
Bush encroachment Namibia, Grazing Management