Thesis (M.S.) -- University of Montana, 2009. / Title from author supplied metadata. Description based on contents viewed on October 14, 2009. Author supplied keywords: Fire, precipitation, season ending event, Remote Automated Weather Stations, North American Regional Reanalysis, Northern Rockies, climate change. Includes bibliographical references.

Thesis (M.S.) -- Mississippi State University. Department of Geosciences. / Title from title screen. Includes bibliographical references.

Thesis (M.S.)--Humboldt State University, 2009. / Includes bibliographical references (leaves 48-53). Also available via Humboldt Digital Scholar.

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 79-86). Also available on the World Wide Web.

Typescript. Includes vita and abstract. Includes bibliographical references (leaves 367-382). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.

At regional scales climate patterns (e.g., interannual wet-dry cycles) result in high spatial fire synchrony among Southwest forests. However, in the "Sky Island" forests of southeastern Arizona spatial and temporal patterns of fire history and tree age structure at landscape levels (i.e., within mountain ranges) are relatively unknown and therefore the focus of this study. In the Santa Catalina Mountains we reconstructed the fire history on a 2,900-hectare study area with two distinct landscapes, Butterfly Peak (BP) and Rose Canyon (RC) using 2-hectare "points" (i.e., collection areas). The RC landscape was dominated by shallow south-facing aspects and BP was dominated by steep north-facing aspects. Within each landscape, point mean fire intervals (PMFIs) were not significantly different between aspect classes. However, pooled PMFIs were significantly shorter in RC compared to BP. These results show that the fire history at any given point (i.e., 2 hectares or less) was primarily controlled by the broad-scale topography of the encompassing landscape, rather than by the fine-scale topography at that point.Using similar methods we also reconstructed the fire history on Rincon Peak, which is a small isolated mountain range with very step topography. The fire history of the 310-hectare forest area was a mixture of frequent low severity surface fires (from AD 1648 to 1763) and infrequent mixed-severity fires (from AD 1763 to 1867). This mixed-fire regime was probably due to a combination of climatic variability, the small area and rugged topography of this mountain range, and complex fuel arrangements. The distinct fire histories from these two study areas provided natural age structure experiments that indicated tree age cohorts (i.e., higher than expected tree establishment pulses) occurred during periods of reduced fire frequencies. In some instances these periods were likely caused by climatic variability (e.g., a wet and/or cool early 1800s) creating synchronous age cohorts across the region. At other times, extended fire intervals were a function of local topography (e.g., 1763-1819 in the northern half of Rincon Peak). Overall, these studies demonstrated that landscape and climatic variations combine to produce complex spatial and temporal variations in fire history and tree age structures.

Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Surface fires are known to affect trees of different species differently, depending on the capacity of the bark to shield the cambium from heat. Tree bark characteristics differ among species and thus potentially influence the protective ability against cambium damage. The objectives of this study were to compare the protective role of bark against fire for selected indigenous and exotic species in the Western Cape, South Africa, and to investigate post-fire growth impacts following surface fire damage on Pinus radiata. In the first part of the study, trees were felled and billets of 25 cm height harvested from different heights along the trunk. Bark thickness, compass direction, stem diameter at breast height, bark moisture content and relative height of the sample in the stem were tested for their effect on heat insulation capacity of bark. Heating experiments were conducted at 400°C on the fresh billets with intact bark. Time to heat the cambium to lethal 60°C was determined. The second part of the study investigated the role of bark surface topology, bark density and bark chemical composition for its fire resistance. The same size billets were harvested from the lower trunk section of selected species. Surface topology was characterised by means of x-ray based computer tomography, density by moisture saturation method and bark chemical composition by thermo-gravimetrical analyses (TGA). The third part of the study investigated the impact of high intensity surface fires on growth of an 18 year old Pinus radiata plantation which was exposed to a ground fire 5 years prior to the analysis. Tree ring measurements were done on cores obtained by non-destructing coring method and various growth indices, based on yearly basal area increment (iBA) used to quantify growth response to the fire damage. Statistical analysis based on correlation, multi-model inference and multiple regression revealed no significant influence of compass direction and diameter at breast height. Heat resistance was mainly determined by bark thickness and to a lesser degree by moisture content. In several species relative height at the stem modulated the bark thickness effect. Higher up the stem bark of the same bark thickness offered less protection against heat. The results also suggest that in particular bark topology plays a role, while the correlations with bark density and chemical composition could not be secured statistically. A main finding was that fissures in the bark play a significant role. A regression model showed a significant influence of fissure width, fissure frequency and the minimum bark thickness to the cambium, which is a function of fissure depth. The results show that structural bark parameters are a necessary addition to explain heat resistance of bark. Statistical analysis employing one-way Anova and incorporating Tamhane’s T2 Post Hoc test revealed significant growth reductions following high intensity surface fire damage on Pinus radiata in the fire year with the impact being passed on to the following year. The recovery phase extended a two year period. During this time the trees showed increased diameter growth probably due to increased water availability. / AFRIKAANSE OPSOMMING: Dit is bekend dat oppervlakvure in bos-ekostelsels verskillende boomspesies verskillend affekteer, afhangende van die vermoë van bas om die kambium van hitte te beskerm. Baseienskappe verskil tussen spesies en het dus 'n potensiële invloed op die beskermende vermoë teen kambiumskade. Die doelwit van hierdie studie was om die beskermende rol van bas teen vuur te vergelyk tussen inheemse en uitheemse spesies in Wes-Kaapland, Suid Afrika asook om die na-vuur impak op groei te ondersoek met brandskade aan Pinus radiata. In die eerste deel van die studie is bome geoes en stompe van 25 cm lengte van verskillende hoogtes verwyder. Basdikte, kompasrigting, stompdiameter by borshoogte, basvoggehalte en die relatiewe hoogte van die stomp in die stam is getoets vir hul invloed op hitte-isolasiekapasiteit van bas. Verhittingseksperimente is gedoen teen 400 °C op die vars stompe wat steeds bas opgehad het. Die tyd om die bas tot by 'n skadelike 60 °C te verhit is bepaal. Die tweede deel van die studie het die rol van basoppervlaktopologie, basdigtheid, en die bas chemiese samestelling ondersoek in vuurweerstand. Dieselfde grootte stompe is geoes van die laer dele van die stam van uitgesoekte spesies. Oppervlaktopologie is bepaal deur middel van X-straal rekenaartomografie, digtheid deur die versadigingsvoggehaltemetode, en chemiese samestelling deur termo-gravimetriese analise (TGA). Die derde deel van die studie het die impak van hoë intensiteit oppervlakvure op groei van 18-jaar oue Pinus radiata ondersoek. Jaarringmetings is gedoen op inkrementboorsels wat nie-destruktief bekom is en verskeie groei-indekse, gebaseer op jaarlikse basale oppervlak aanwas, is gebruik om die groeireaksie op brandskade te kwantifiseer. Statistiese analise gebaseer op korrelasie, multi-model inferensie, en veelvuldige regressie het gewys dat kompasrigting en deursnee op borshoogte nie 'n beduidende invloed gehad het nie. Hitteweerstand was hoofsaaklik bepaal deur basdikte, en in 'n mindere mate basvoggehalte. By verskeie spesies het die relatiewe hoogte die basdikte-effek gemoduleer. Hoër in die stam het dieselfde dikte bas minder beskerming gebied as bas van laer in die stam. Die resultate impliseer dat basoppervlaktopologie ook 'n rol speel in hitteweerstand terwyl basdigtheid en chemiese samestelling nie 'n statisties beduidende rol gespeel het nie. 'n Belangrike bevinding was dat gleuwe of openinge in die bas 'n beduidende rol speel. 'n Regressiemodel wys dat 'n beduidende invloed deur gleufwydte, gleuffrekwensie en die minimum basdikte na die kambium. Die resultate wys dat strukturele basparameters 'n belangrike bykomende rol speel om hitteweerstand van bas te verduidelik. Die statistiese analise waar eenrigting ANOVA met Tamhane se T2 Post Hoc toets gebruik is toon dat ‘n beduidende groeivermindering teweeg gebring is in die Pinus radiata as gevolg van skade veroorsaak deur hoë intensiteit oppervlakvure waarvan die impak eers in die jaar na die vuur sigbaar was. Die herstelfase het oor twee jaar gestrek. Gedurende hierdie tyd het die bome 'n toename in deursneegroei getoon, waarskynklik as gevolg van verhoogde waterbeskikbaarheid.

This study was conducted in the Afram Headwaters, Tain Tributaries Block II and Worobong South Forest Reserves. Satellite record of fire incidence for the country over 11 years (1997 to 2007) was modelled via binary logistic regression analysis, and correlations between fire incidence and the correlates of fire used to explain the observed trends. Fire incidence was found to be correlated with multiple variables which probably covary. Rainfall, vegetation type and geology showed the strongest correlations with fire incidence. Recurrent fire has impacted negatively on forest structure, ground cover biomass and species composition in two forest reserves, but more marked in the wetter Worobong South Forest Reserve than the drier Tain II Forest Reserve. Basal area has reduced from 40 m²ha^-1 in least-degraded to <1 m²ha^-1 in heavily-degraded stand in Worobong South Forest Reserve, along with tree density, whereas canopy openness has increased from 6% in least-degraded to 83% in heavily-degraded forest. In Tain II Forest Reserve, however, the heavily-degraded forest has lost close to 50% of its maximum value in terms of basal area, tree density and canopy cover, all in approximately 20 years. Early-burning, with maximum seedling height growth rates of 130 cm yr^-1 and 40 cm yr^-1 for Worobong South and Tain II Forest Reserves respectively, might help control the fires, and restore forest canopy in about 10 to 20 years if regularly maintained, but must be accompanied by green firebreaks. Complete protection from fire (during convalescence), on the other hand, would take between five and 15 years to restore forest canopy, but at huge resource cost. Implications for sustainable forest management are discussed.

"This thesis evaluates the effectiveness of BEHAVE: Fire Behavior Prediction and Fuel Modeling System in predicting fire behavior in the Northeastern pine-oak forest. This fuel complex is composed primarily of a litter and huckleberry shrub understory with a pitch pine and oak overstory. Measurements of fuel bed physical characteristics, weather and fire behavior are taken from a series of prescribed burn studies in Cape Cod National Seashore in Massachusetts. Site-specific fuel models are constructed which provide the necessary inputs for fire predictions. Observed spread rates and flame lengths are over-predicted by BEHAVE for burns conducted during the winter (dormant season) and under-predicted for burns conducted during the summer (growing season). Attempts to improve winter predictions are successful when the litter moisture is adjusted in order to account for the live wintergreen which increases the overall moisture content of the surface fuels. A sensitivity study is performed where each input parameter is varied over a reasonable interval in order to view its impact on predictions. The model’s high sensitivity to fuel bed depth and 1-hr surface-area-to-volume ratio appear to be the cause for fire prediction deviations during the winter, while the high live fuel moisture contents appear to overwhelm and suppress fire behavior predictions during the summer. It is concluded to overwhelm and suppress fire behavior predictions during the summer. It is concluded that BEHAVE’s representation of fuel complexes as a homogeneous fuel bed with constant properties does not take into account the unique features of the litter and shrub components. An alternative, simple model of fire spread is developed which treats each component as a separate fuel bed. The model is based on a measurement of the heat release rate which can be determined directly through the principle of oxygen consumption calorimetry. Future work using small- and large- scale testing apparatus will help determine the ignition process of the live shrubs and the effect of parameters such as moisture content on the burning characteristics of the fuels. "

Thesis (M.S.) in Forestry--University of Maine, 2004. / Includes vita. Includes bibliographical references (leaves 104-115).