Nipping the bud hypothesis : a comparison of savannah and forest tree responses to canopy scorch

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dc.contributor.advisorBond, William Jen_ZA
dc.contributor.authorBeckett, Heathen_ZA
dc.date.accessioned2017-08-08T06:48:54Z
dc.date.available2017-08-08T06:48:54Z
dc.date.issued2010en_ZA
dc.description.abstractTree mortality, following surfaces fires, is much greater in forests than in savannas, despite similarities in the bark thickness of tree trunks. This difference is thought to influence the distributions of forest and savanna biomes. There is no consensus and very little research on how fires actually kill trees. Though tree canopies are too high above the flames to be charred, leaves are often scorched over the full tree height; hence the focus on differences in tree canopy recovery. I explored two possible mechanisms for differences in crown resprouting following canopy scorch: (1) differences in bud banks and their insulation, (2) differences in the vulnerability to disruption of the hydraulic system by heat scorch. I simulated canopy scorch using nine congeneric savanna-forest pairs in three Reserves in KwaZulu Natal, South Africa. Contrary to predictions, there was no difference in the presence of a viable bud bank between congeneric species. The resprouting response varied between congeneric pairs with only the Combretum, Rhus and Acacia pairs showing savanna species with a significantly greater ability to resprout. The vulnerability to hydraulic disruption was measured using wood density as a proxy for conduit reinforcement. The results are inconclusive and possibly affected by the growth rates of certain shade-tolerant forest trees. The differences in crown resprouting following canopy scorch of forest and savanna trees is not the result of differences in bud banks and resprouting ability. The differences in insulation of vulnerable tissue by bark may be related to the protection of the hydraulic system rather than the buds and/or cambium.en_ZA
dc.identifier.apacitationBeckett, H. (2010). <i>Nipping the bud hypothesis : a comparison of savannah and forest tree responses to canopy scorch</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/24851en_ZA
dc.identifier.chicagocitationBeckett, Heath. <i>"Nipping the bud hypothesis : a comparison of savannah and forest tree responses to canopy scorch."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2010. http://hdl.handle.net/11427/24851en_ZA
dc.identifier.citationBeckett, H. 2010. Nipping the bud hypothesis : a comparison of savannah and forest tree responses to canopy scorch. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Beckett, Heath AB - Tree mortality, following surfaces fires, is much greater in forests than in savannas, despite similarities in the bark thickness of tree trunks. This difference is thought to influence the distributions of forest and savanna biomes. There is no consensus and very little research on how fires actually kill trees. Though tree canopies are too high above the flames to be charred, leaves are often scorched over the full tree height; hence the focus on differences in tree canopy recovery. I explored two possible mechanisms for differences in crown resprouting following canopy scorch: (1) differences in bud banks and their insulation, (2) differences in the vulnerability to disruption of the hydraulic system by heat scorch. I simulated canopy scorch using nine congeneric savanna-forest pairs in three Reserves in KwaZulu Natal, South Africa. Contrary to predictions, there was no difference in the presence of a viable bud bank between congeneric species. The resprouting response varied between congeneric pairs with only the Combretum, Rhus and Acacia pairs showing savanna species with a significantly greater ability to resprout. The vulnerability to hydraulic disruption was measured using wood density as a proxy for conduit reinforcement. The results are inconclusive and possibly affected by the growth rates of certain shade-tolerant forest trees. The differences in crown resprouting following canopy scorch of forest and savanna trees is not the result of differences in bud banks and resprouting ability. The differences in insulation of vulnerable tissue by bark may be related to the protection of the hydraulic system rather than the buds and/or cambium. DA - 2010 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2010 T1 - Nipping the bud hypothesis : a comparison of savannah and forest tree responses to canopy scorch TI - Nipping the bud hypothesis : a comparison of savannah and forest tree responses to canopy scorch UR - http://hdl.handle.net/11427/24851 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/24851
dc.identifier.vancouvercitationBeckett H. Nipping the bud hypothesis : a comparison of savannah and forest tree responses to canopy scorch. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2010 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/24851en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherBotanyen_ZA
dc.subject.otherPlant Ecologyen_ZA
dc.titleNipping the bud hypothesis : a comparison of savannah and forest tree responses to canopy scorchen_ZA
dc.typeBachelor Thesis
dc.type.qualificationlevelHonours
dc.type.qualificationnameBSc (Hons)en_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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