Retrospective determination of exposure temperature of standing trees during wildfires with Solid-state NMR

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dc.contributor.advisorMeincken, Martinaen_ZA
dc.contributor.authorKutzer, Karlen_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Forest and Wood Science.en_ZA
dc.date.accessioned2024-02-22T14:35:13Zen_ZA
dc.date.accessioned2024-04-26T11:38:41Zen_ZA
dc.date.available2024-02-22T14:35:13Zen_ZA
dc.date.available2024-04-26T11:38:41Zen_ZA
dc.date.issued2024-02en_ZA
dc.descriptionThesis (MSc)--Stellenbosch University, 2024.en_ZA
dc.description.abstractENGLISH ABSTRACT: Timber plantations across the world are suffering from the effects of increasingly frequent wildfires, which potentially degrade the wood of affected trees, depending on the exposure temperature. However, it is rather complicated to determine the exact temperature of the fire, or the temperature to which the wood behind the bark was exposed. This study aimed to determine the exposure temperature of the wood retrospectively through Solid-state NMR (ssNMR) analysis. Models were developed from softwood and hardwood samples exposed to defined temperatures in a laboratory furnace, which successfully linked the NMR signal to the exposure temperature. Various equations were tested to fit either the half-width or peak area of the NMR signals obtained for different exposure temperatures and the best models were identified. The results show a clear difference between Pine and Eucalyptus wood: for Pine the half-width of the NMR signal yielded the best correlation to exposure temperature, while for Eucalyptus the peak area was a better fit. The results confirmed findings of an earlier pilot study performed on Pine with an increased sample number over a larger temperature range and extended the model to a hardwood species, namely Eucalyptus. This non-destructive method offers a valuable evaluation method to determine, if the wood from burnt trees is still sound and can be further processed. If models are developed for the relevant species used by the South African Forest industry, significant economic gains can be made, by not unilaterally discarding burnt trees where the wood of many trees has not been degraded and can still be utilized.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Houtplantasies regoor die wêreld gaan gebuk onder die gevolge van toenemende gereelde veldbrande, wat moontlik die hout van geaffekteerde bome afbreek, afhangende van die blootstellingstemperatuur. Dit is egter taamlik ingewikkeld om die presiese temperatuur van die vuur te bepaal, of die temperatuur waaraan die hout agter die bas blootgestel is. Hierdie studie het ten doel gehad om die blootstellingstemperatuur van die hout retrospektief te bepaal deur middel van Vastetoestand KMR (ssKMR) analise. Modelle is ontwikkel uit sagtehout- en hardehoutmonsters wat aan gedefinieerde temperature in 'n laboratoriumoond blootgestel is, wat die KMR-sein suksesvol aan die blootstellingstemperatuur gekoppel het. Verskeie vergelykings is getoets om óf die halfwydte óf piekarea van die KMR-seine wat vir verskillende blootstellingstemperature verkry is te pas en die beste modelle is geïdentifiseer. Die resultate toon 'n duidelike verskil tussen denne- en bloekomhout: vir denne het die halfwydte van die KMR-sein die beste korrelasie met blootstellingstemperatuur gelewer, terwyl vir bloekom die piekarea 'n beter passing was. Die resultate het bevindinge bevestig van 'n vroeëre loodsstudie wat op Pine uitgevoer is met 'n verhoogde monstergetal oor 'n groter temperatuurreeks en het die model uitgebrei na 'n hardehoutspesie, naamlik Eucalyptus. Hierdie nie-vernietigende metode bied 'n waardevolle evalueringsmetode om te bepaal of die hout van gebrande bome nog gesond is en verder verwerk kan word. Indien modelle ontwikkel word vir die betrokke spesies wat deur die Suid-Afrikaanse Bosbedryf gebruik word, kan aansienlike ekonomiese winste gemaak word deur nie eensydig verbrande bome weg te gooi waar die hout van baie bome nie afgebreek is nie en steeds benut kan word.af_ZA
dc.description.versionMastersen_ZA
dc.format.extentv, 48 pages : illustrations.en_ZA
dc.identifier.urihttps://scholar.sun.ac.za/handle/10019.1/130274en_ZA
dc.language.isoen_ZAen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshPlantations -- Africa, Southernen_ZA
dc.subject.lcshWildfires -- Africa, Southernen_ZA
dc.subject.lcshFynbos ecology -- Africa, Southernen_ZA
dc.subject.lcshEucalyptus -- Ecology -- Africa, Southernen_ZA
dc.subject.lcshUCTDen_ZA
dc.titleRetrospective determination of exposure temperature of standing trees during wildfires with Solid-state NMRen_ZA
dc.typeThesisen_ZA
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