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Are forests restricted by nutrient poor soils? : an analysis of soil nutrient stocks and associated vegetation in the fynbos biome, South Africa
The realized woody biomass of the Fynbos Biome in the Western Cape, South Africa falls below the climatic potential to support woody biomass. The lack of substantial tracts of woody forests has long puzzled ecologists, although patchy nutrient distribution and fire disturbance are thought to play a...
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| Format: | Thesis |
| Language: | English |
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Department of Biological Sciences
2017
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| _version_ | 1867613253226463232 |
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| access_status_str | Open Access |
| author | Donaldson, Jason |
| author2 | Cramer, Michael D |
| author_browse | Cramer, Michael D Donaldson, Jason |
| author_facet | Cramer, Michael D Donaldson, Jason |
| author_sort | Donaldson, Jason |
| collection | Thesis |
| description | The realized woody biomass of the Fynbos Biome in the Western Cape, South Africa falls below the climatic potential to support woody biomass. The lack of substantial tracts of woody forests has long puzzled ecologists, although patchy nutrient distribution and fire disturbance are thought to play a role. The issue has been confounded in the recent past by the invasion of non-indigenous woody plants into formerly low stature fynbos dominated areas. Despite low wood nutrient concentrations, a substantial proportion of nutrients are locked up in the wood of forests due to the large volume of wood. Nevertheless, nutrient stock analysis indicated that plant available nutrients in the poorest global soils (including fynbos soils) are sufficient to support forests (indigenous and alien). I hypothesized that soil nutrient stocks of the Fynbos Biome are sufficient in quantity to support closed canopy indigenous forests with a woody biomass greater than 225 000 kg ha⁻¹ and that alien Pinus spp. and Eucalyptus spp. have lower nutrient stocks than indigenous fynbos species. The study was conducted in the Orange Kloof Forest Reserve and Jonkershoek Nature Reserve within the Western Cape (South Africa). Soil, wood and leaf samples of representative species were collected from indigenous forest, fynbos, E. globulus and P. halepensis and assessed for nutrient contents. Estimates of potential woody biomass on four different soils indicated that indigenous forests would be limited by fynbos soil stocks to below the 225 000 kg ha⁻¹. Pine forest had lower wood nutrient concentrations (mg kg⁻¹, n=6) for N (2466), K (2433), Ca (383), and Fe (34) than indigenous forest species (n=11) N (3427), K (4254), Ca (1636) and Fe (140). The low nutrient stocks in pine wood may allow them to grow tall and be competitive in the shrubby fynbos biome where indigenous forests are limited by expensive wood costs. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/26584 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:12.104Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2017 |
| publishDateRange | 2017 |
| publishDateSort | 2017 |
| publisher | Department of Biological Sciences |
| publisherStr | Department of Biological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/26584 Are forests restricted by nutrient poor soils? : an analysis of soil nutrient stocks and associated vegetation in the fynbos biome, South Africa Donaldson, Jason Cramer, Michael D Botany The realized woody biomass of the Fynbos Biome in the Western Cape, South Africa falls below the climatic potential to support woody biomass. The lack of substantial tracts of woody forests has long puzzled ecologists, although patchy nutrient distribution and fire disturbance are thought to play a role. The issue has been confounded in the recent past by the invasion of non-indigenous woody plants into formerly low stature fynbos dominated areas. Despite low wood nutrient concentrations, a substantial proportion of nutrients are locked up in the wood of forests due to the large volume of wood. Nevertheless, nutrient stock analysis indicated that plant available nutrients in the poorest global soils (including fynbos soils) are sufficient to support forests (indigenous and alien). I hypothesized that soil nutrient stocks of the Fynbos Biome are sufficient in quantity to support closed canopy indigenous forests with a woody biomass greater than 225 000 kg ha⁻¹ and that alien Pinus spp. and Eucalyptus spp. have lower nutrient stocks than indigenous fynbos species. The study was conducted in the Orange Kloof Forest Reserve and Jonkershoek Nature Reserve within the Western Cape (South Africa). Soil, wood and leaf samples of representative species were collected from indigenous forest, fynbos, E. globulus and P. halepensis and assessed for nutrient contents. Estimates of potential woody biomass on four different soils indicated that indigenous forests would be limited by fynbos soil stocks to below the 225 000 kg ha⁻¹. Pine forest had lower wood nutrient concentrations (mg kg⁻¹, n=6) for N (2466), K (2433), Ca (383), and Fe (34) than indigenous forest species (n=11) N (3427), K (4254), Ca (1636) and Fe (140). The low nutrient stocks in pine wood may allow them to grow tall and be competitive in the shrubby fynbos biome where indigenous forests are limited by expensive wood costs. 2017-12-12T14:25:07Z 2017-12-12T14:25:07Z 2011 Bachelor Thesis Honours BSc (Hons) http://hdl.handle.net/11427/26584 eng application/pdf Department of Biological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Botany Donaldson, Jason Are forests restricted by nutrient poor soils? : an analysis of soil nutrient stocks and associated vegetation in the fynbos biome, South Africa |
| thesis_degree_str | Bachelor's / Honours |
| title | Are forests restricted by nutrient poor soils? : an analysis of soil nutrient stocks and associated vegetation in the fynbos biome, South Africa |
| title_full | Are forests restricted by nutrient poor soils? : an analysis of soil nutrient stocks and associated vegetation in the fynbos biome, South Africa |
| title_fullStr | Are forests restricted by nutrient poor soils? : an analysis of soil nutrient stocks and associated vegetation in the fynbos biome, South Africa |
| title_full_unstemmed | Are forests restricted by nutrient poor soils? : an analysis of soil nutrient stocks and associated vegetation in the fynbos biome, South Africa |
| title_short | Are forests restricted by nutrient poor soils? : an analysis of soil nutrient stocks and associated vegetation in the fynbos biome, South Africa |
| title_sort | are forests restricted by nutrient poor soils an analysis of soil nutrient stocks and associated vegetation in the fynbos biome south africa |
| topic | Botany |
| url | http://hdl.handle.net/11427/26584 |
| work_keys_str_mv | AT donaldsonjason areforestsrestrictedbynutrientpoorsoilsananalysisofsoilnutrientstocksandassociatedvegetationinthefynbosbiomesouthafrica |