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The effects of repeated under canopy burning operations in commercial Pine plantations in Mpumalanga, South Africa on fuel loads and stand productivity
Thesis (MFor)--Stellenbosch University, 2021.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2021
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| _version_ | 1867613953104805888 |
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| access_status_str | Open Access |
| author | Pickup, Christopher Dale |
| author2 | Du Toit, Ben |
| author_browse | Du Toit, Ben Pickup, Christopher Dale |
| author_facet | Du Toit, Ben Pickup, Christopher Dale |
| author_sort | Pickup, Christopher Dale |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MFor)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/110524 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:44:19.493Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/110524 The effects of repeated under canopy burning operations in commercial Pine plantations in Mpumalanga, South Africa on fuel loads and stand productivity Pickup, Christopher Dale Du Toit, Ben Stellenbosch University. Faculty of AgriSciences. Dept. of Forest and Wood Science. Fuel load reduction UCTD Prescribed burning Fuel load reduction Forest fires Wildfires -- Prevention Forest canopies Fires -- Risk mitigation Thesis (MFor)--Stellenbosch University, 2021. ENGLISH ABSTRACT: Wild fires are a risk to commercial forestry companies in South Africa resulting in commercial areas being damaged or destroyed. Viable methods to mitigate this risk in an effective, economical and sustainable manner need to be practised to ensure the sustainability of the forestry industry in South Africa. Prescribed under canopy burning is a viable option to reduce fire risk and fire damage and is implemented in South Africa. This thesis documents the effects of repeated prescribed under canopy burning operations on fuel load reduction, stand productivity as well as the effect on tree damage. Three trial sites were selected in Mpumalanga, South Africa; namely Blyde plantation, Berlin plantation and Nelshoogte plantation. Two trial sites consist of three control plots, three twice burnt plots and three plots burnt on three occasions. One trial site (Blyde) consists of three once burnt plots and three plots burnt on three occasions. The trials commenced in 2014 with the third burn treatments being implemented during 2019, and final measurements in 2020. Burning conditions and fire intensity: Under canopy burning treatments were of a low intensity. Average fire front flame heights were 0.20m and average fire line intensity ranged between 4 kw/m to 11 kw/m. The average surface rate of spread ranged between 0.1m/min and 0.2m/min and the surface fire heat per unit area ranged between 3080 kJ/m2 and 4089 kJ/m2. These low intensity burning treatments resulted in minimal tree damage on most plots. Forest floor mass: Forest floor mass was reduced on all three trial sites. Pinus patula trial sites experienced an average reduction of 16.3 t/ha per burning treatment and the Pinus elliottii trial site experienced an average reduction of 4.5 t/ha. The total forest floor fuel load reduction in areas that have never received a burning treatment compared to sites that received 3 burning treatments is an average difference of 48.8 t/ha in Pinus patula stands. The reduction in the forest floor fuel load for sites that received 1 burning treatment and 3 burning treatments in Pinus elliottii stands is 9 t/ha. The degree of fuel load reduction is statistically significant in Pinus patula and Pinus elliottii stands. Tree damage: No tree mortality occurred in the Pinus elliottii trial stand, however tree mortality was observed on both the Pinus patula trial sites. Tree mortality occurred in unburnt plots, as well as plots that received burning treatments. No correlation between tree mortality and burning treatments could be established. Root damage was observed on all three trial sites. A minor degree of root damage occurred and only one observed tree was found to have root damage in the coarse root class. No crown damage was observed to have occurred directly after burning. Litter fall was observed for 7 months and an increase in litter fall occurred after the burning treatment on the Nelshoogte trial site due to a higher fire intensity on the day of the burn. Average monthly litter fall rates ranged from 1 t/ha to 0.2 t/ha in Pinus elliottii with the highest amount of needle drop occurring in the winter months and the least occurring in the spring/summer months. Pinus patula sites experienced an average range of needle drop from 1.5 t/ha to 0.3 t/ha with the highest amount of needle drop occurring in the winter months and least occurring in the spring/summer months. Growth responses: Erratic differences in growth increment were observed, indicating that the impact of the specific site had a significant impact on growth responses. The low intensity burning treatments had an insignificant impact on growth responses on the Blyde site. There was a significant interaction between site and burning treatments among the Pinus patula trials. The Nelshoogte site experienced the highest fire intensity during the burning treatment, this site also experienced the highest degree of root damage as well as a decrease in Periodic Annual Increment (PAI) of 4 m3/ha/a. In contrast, the Berlin experiment showed a significant increase in PAI following repeated burning amounting to 3 m3/ha/a. AFRIKAANSE OPSOMMING: Onbeheerde brande is 'n risiko vir kommersiële bosbouondernemings in Suid-Afrika, wat daartoe lei dat kommersiële gebiede beskadig of vernietig word. Lewensvatbare metodes om hierdie risiko effektief, ekonomies en volhoubaar te verlaag, moet toegepas word om die volhoubaarheid van die bosboubedryf in Suid-Afrika te verseker. Voorgeskrewe brande onder die kroondak van plantasies is 'n lewensvatbare opsie om brandrisiko en brandskade te verminder en word in Suid-Afrika geïmplementeer. Hierdie tesis dokumenteer die effek van herhaalde voorgeskrewe brande onder die kroondak op die verlaging van die brandstoflading, opstandsproduktiwiteit asook die effek op boomskade. Drie proefpersele is in Mpumalanga, Suid-Afrika, gekies; naamlik Blyde, Berlin en Nelshoogte plantasies. Die behandelings verskil in die aantal beheerde brande wat onder die kroondak gedoen is. Twee eksperimente bestaan uit drie ongebrande kontrole persele, asook drie persele wat twee maal en drie persele wat drie maal gebrand is. Een eksperiment bestaan uit drie eenmalige gebrande persele en drie persele wat drie keer gebrand is. Die drie eksprimente is in 2014 begin, die derde beheerde brandbehandelings is gedurende 2019 geïmplementeer, en die finale metings is in 2020 gedoen. Brandtoestande en vuurintensiteit: Beheerde brande onder die kroondak was van lae intensiteit. Die gemiddelde vlamhoogte van die brandfront was 0,20 m en die gemiddelde brandlyn intensiteit het gewissel tussen 4 en 11 kW/m. Die gemiddelde verspreidingstempo het gewissel tussen 0.1 en 0.2 m/min en die oppervlak vuurhitte per eenheidsarea het gewissel tussen 3080 en 4089 kJ/m2. Hierdie lae intensiteit brandbehandelings het minimale boomskade tot gevolg gehad. Bosvloermassa: Die bosvloermassa is op al drie proefpersele verlaag deur die beheerde brand. Pinus patula-proefpersele het 'n gemiddelde verlaging van 16.3 t/ha per brandbehandeling ervaar en die Pinus elliottii-proefperseel het 'n gemiddelde vermindering van 4.5 t / ha ervaar. Die totale verlaging van die brandstofbelasting op die bosvloer in ongebrande persele vergeleke met plekke wat 3 brandbehandelings ontvang het, is 'n gemiddelde verskil van 48.8 t/ha in Pinus patula-opstande. Die finale verskil in brandstoflading tussen een en drie brandebhadelings op die bosvloer in Pinus elliottii persele, is 9 t/ha. Die mate van brandstof reduksie is statisties beduidend in beide Pinus patula en Pinus elliottii opstande. Boomskade: Geen boomsterftes het voorgekom in die Pinus elliottii proef nie. Daar is egter boomsterftes op beide die Pinus patula proefpersele waargeneem. Boomsterfte het egter voorgekom in ongebrande behandelings sowel as persele wat brandbehandelings ontvang het. Geen korrelasie tussen boomsterftes en brandbehandelings kon vasgestel word nie. Wortelskade is op al drie proefpersele waargeneem. 'n Geringe mate van wortelskade het oor die algemeen voorgekom en slegs een enkele boom in die waargenome steekproef het wortelskade in die dikste wortelklas gehad. Geen kroonbeskadiging is waargeneem direk na beheerde brande nie. Tempo van naaldeval is vir 7 maande na brand waargeneem. 'n Geringe toename in naaldeval het plaasgevind na die brandbehandeling op die Nelshoogte-proefperseel as gevolg van 'n hoër vuurintensiteit op die dag van die brand. Die gemiddelde maandelikse naaldeval het tussen 0.2 en 1.0 t/ha in Pinus elliottii, met die hoogste hoeveelheid in die wintermaande en die minste in die lente / somermaande. Pinus patula persele het 'n gemiddelde naaldeval van 0.3 tot 1.5 t/ha ondervind, met die hoogste hoeveelheid naaldeval in die wintermaande en die minste in die lente / somermaande. Groeireaksie: Wisselvallige reaksie in opstandsgroei is waargeneem, wat daarop dui dat die effek van die vuurintensiteit en die groeiplek 'n beduidende impak op die opstande se groeireaksie gehad het. Die brandbehandelings met lae intensiteit het 'n onbeduidende impak gehad op die periodieke jaarlikse aanwas (PJA) van die Pinus elliotti opstand op Blyde plantasie. Daar was 'n beduidende interaksie tussen behandelings en groeiplek onder die Pinus patula-eksperimente. Die Nelshoogte eksperiment het die hoogste brandintensiteit ervaar tydens die brandbehandeling; hierdie proef het ook die hoogste mate van wortelskade ervaar, asook 'n afname in PJA van 4 m3/ha/a. Daarteenoor het die Berlin plantasie eksperiment 'n beduidende toename in PJA getoon van 3 m3/ha/a na herhaalde beheerde brand. Masters 2021-05-31T09:49:04Z 2021-05-31T09:49:04Z 2021-03 Thesis http://hdl.handle.net/10019.1/110524 en_ZA Stellenbosch University 107 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Fuel load reduction UCTD Prescribed burning Fuel load reduction Forest fires Wildfires -- Prevention Forest canopies Fires -- Risk mitigation Pickup, Christopher Dale The effects of repeated under canopy burning operations in commercial Pine plantations in Mpumalanga, South Africa on fuel loads and stand productivity |
| title | The effects of repeated under canopy burning operations in commercial Pine plantations in Mpumalanga, South Africa on fuel loads and stand productivity |
| title_full | The effects of repeated under canopy burning operations in commercial Pine plantations in Mpumalanga, South Africa on fuel loads and stand productivity |
| title_fullStr | The effects of repeated under canopy burning operations in commercial Pine plantations in Mpumalanga, South Africa on fuel loads and stand productivity |
| title_full_unstemmed | The effects of repeated under canopy burning operations in commercial Pine plantations in Mpumalanga, South Africa on fuel loads and stand productivity |
| title_short | The effects of repeated under canopy burning operations in commercial Pine plantations in Mpumalanga, South Africa on fuel loads and stand productivity |
| title_sort | effects of repeated under canopy burning operations in commercial pine plantations in mpumalanga south africa on fuel loads and stand productivity |
| topic | Fuel load reduction UCTD Prescribed burning Fuel load reduction Forest fires Wildfires -- Prevention Forest canopies Fires -- Risk mitigation |
| url | http://hdl.handle.net/10019.1/110524 |
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