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Post-fire micro-habitat and plant regeneration in heathlandMallik, A. U. January 1982 (has links)
No description available.
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Hydrological Analysis Of Post-Fire Responses Within The Little Creek Watershed Of Swanton Pacific RanchWiens, Alexander Jeffrey 01 June 2024 (has links) (PDF)
Climate change and a growing wildland-urban interface are associated with an increase in the number and severity of wildfires. While severe wildfires do cause a costly and dangerous impact on the environment and the public, their after-effects comprise important subjects of study. In post-fire hydrologic studies, the reduced infiltration and plant cover that results from wildfires can commonly be associated with increased peakflows and erosion. Phenomena such as the flooding and debris flows in Montecito after the Thomas Fire in late 2017 can have important implications on infrastructure and human lives. Quantifying post-fire peak flows and flooding volumes has therefore become a special study of interest. However, the few studies that exist on post-fire hydrology across the United States have inconclusive and flawed results. Post-fire hydrological studies on coastal-redwood forests are also lacking in both number and quality.
These research gaps were addressed through a three-year, post-fire hydrological study on the Litte Creek watershed of Swanton Pacific Ranch in Davenport, CA. The study took place from the 2021 to 2024 hydrological years (HY). Hydrographs and rating curves were developed to yield results for post-fire conditions. A frequency analysis utilizing Log Pearson Type III and Weibull calculations yielded post-fire results according to 0.5-, 1-, 2-, and 5-year return intervals. A statistical model based on precipitation, antecedent precipitation index, and streamflow data modelled pre-fire values. Subsequently, the pre- and post-fire peak flows and storm volumes were compared. The post-fire results from the analysis were also compared to those estimated from the USGS Linear Regression method and the RF-5 method from Wilder et al, 2020.
It was found that a slight increase in post-fire peak flows and storm volumes occurred upon comparison to pre-fire values, primarily for the South Fork of the watershed. This observation was found to be present for flows and volumes below a 0.5-year return interval, with higher uncertainty beyond that threshold. The USGS and Wilder methods were found to v inaccurately predict the post-fire peak flows. However, calculation of USGS-Regression parameters for two areas (Main Stem and South Fork) yielded percent increases in post-fire peak flows (between 19-31%) and percent-runoff increases (between 36-59%) for peak flows between return intervals of 0.5 to 5 years. Results were found to be mostly statistically significant for all three sites (α < 0.05), except for the North-Fork site in several cases and some model intercepts across all three sites. Incision and erosion of streambeds and the recovery of vegetation since the 2020 fire may have played an underlying role in the study. Despite some errors in stage data, the small increases in post-fire parameters, and variations in burn-area conditions, the study represented a motivated attempt to use linear regression on post-fire hydrologic data and to improve upon the site’s previous study through a more comprehensive dataset. This attempt serves as one of many in studying post-fire hydrology, which serves to inform better decisions for wildfire, flood-management, and land-management agencies.
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A Comparison of Fire Severity Effects on Post Fire Vegetation Recovery Nine Years Following the Rodeo-Chediski Fire: A Long Term Monitoring StudyJanuary 2012 (has links)
abstract: Two nearly homogenous 60 acre watersheds near Heber, Arizona, within the Apache-Sitgreaves National Forest, were burned at moderate and high severities during the 2002 Rodeo-Chediski wildfire. Each watershed had 30 permanent plots located on it from earlier studies. In 2011, nearly 10 years following the fire, the plots were re-measured to determine how fire severity affects the long term vegetative recovery of this ecosystem; specifically herbaceous production and tree regeneration and density. Canopy cover, litter depth, herbaceous weight, herbaceous cover and shrub cover are vital indicators of herbaceous production, and were found to be significantly different between the sites. Canopy cover and litter depth were found to be significantly higher on the moderate site while herbaceous weight, herbaceous cover and shrub cover were found to be significantly higher on the high site. Tree densities of the three present tree species, ponderosa pine, alligator juniper, and gambel oak, were measured and divided into five size classes to distinguish the diversity of the communities. The mean densities for each species and size class were analyzed to determine if there were any statistically significant differences between the sites. Ponderosa pine saplings (regeneration) were found to have no significant differences between the sites. Juniper and oak saplings were found to be significantly higher on the high site. The remaining four ponderosa pine size classes were found to be significantly higher on the moderate site while the remaining four size classes for juniper and oak were found to have no statistical differences between the sites. Further analysis of the tree proportions revealed that the ponderosa pine species was significantly higher on the moderate site while juniper and oak were significantly higher on the high site. Species specific proportion analysis showed that the ponderosa pine size classes were significantly different across the sites while the juniper and oak size classes showed no significant differences between the sites. Within the ponderosa pine size classes, saplings were found to be significantly higher on the high site while the remaining four classes were significantly higher on the moderate site. / Dissertation/Thesis / M.S. Applied Biological Sciences 2012
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Erosion Processes and ControlGarcia-Chevesich, Pablo Andres January 2009 (has links)
This dissertation represents a unique contribution to the Spanish literature of soil erosion. The author of this document has written and published "Procesos y control de la erosion", a textbook about the engineering of soil erosion processes and the design of the most up-to-date methods and products used for erosion control. The text has been presented in Appendix A.Besides the above, the author of this dissertation is an active committee member at the International Erosion Control Association (IECA), specifically the International Development and the SOIL Fund programs. IECA members are drawn from individuals and erosion control business of different sizes. However, there was a lack of knowledge within IECA members about the formation of post-fire water repellent layers. For instance, Appendix B is represented by an article written by the author of this document, published in Environmental Connection (Volume 2, Issue 3), on July of 2008. The article gives a general description of what post-fire water repellency is, how is it formed, what factors affect it, its consequences on soil erosion, and how to control soil erosion on an efficient way when such a layer has been formed as a consequence of fire.Finally, Appendix C is a research paper in process of submission to the International Journal of Wildland Fire, about the formation of post-fire water repellent layers on Chilean Monterrey pine plantations. Since water repellent layers following wildfires have never been documented on Chilean soils, the need for such a publication is urgent, because Chilean land managers have been ignorant of such phenomenon.
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Post-Fire Assessment of Concrete Tunnel StructuresMenz, Nicholas C 01 July 2021 (has links)
Although concrete tunnel structures can lose strength and long-term durability due to fire, the literature on the remaining capacity of structures after fire events is very scattered, and no published post-fire inspection protocols specifically for concrete tunnel structures are available. This work aims to summarize and synthesize the current state of knowledge of the deleterious effects of fire on the residual condition of concrete tunnel structures and how the extent and degree of fire damage can be assessed. The scope of this work includes an extensive literature review, heat testing of some common tunnel elements, and residual strength testing of a tunnel wall panel. The literature review includes a review of published standards, technical reports, academic papers, and a survey of post-fire inspection practices at other state DOTs and transit organizations. Topics covered in the review include the residual mechanical properties of concrete, steel, and the concrete/steel bond after fire, the residual strength and stiffness of structural members after fire, existing inspection tools and methods for assessing concrete structures after fire, and repair methods for fire-damaged concrete structures. The outcomes of the heat testing are presented, including the setup of a radiant heating system (which does not use a flame), procurement of sample specimens for testing, thermal and physical testing of specimens, and evaluation of results. Lastly, based on the literature review and experimental testing, recommendations for future work are presented.
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Post-Fire Succession and Disturbance Interactions on an Intermountain Subalpine Spruce-Fir ForestDicus, Christopher A. 01 May 1995 (has links)
Four general post-fire successional pathways leading to a climax Engelmann spruce (Picea engelmannii Parry)/subalpine fir (Abies lasiocarpa [Hook] Nutt.) forest were identified operating on the T.W. Daniel Experimental Forest in northern Utah. These included initial colonization by seral quaking aspen (Populus tremuloides Michx.), seral lodgepole pine (Pinus contorta Dougl. ex Loud.), colonization by lodgepole pine followed by a low intensity surface fire, and immediate colonization by late successional Engelmann spruce and subalpine fir.
Post-fire establishment of the late successional species occurred earliest in the Engelmann spruce/subalpine fir pathway followed by the lodgepole pine and lodgepole pine ground fire pathways, and the quaking aspen pathway . The late successional species 11 grew fastest in the Engelmann spruce/subalpine fir pathway followed by the quaking aspen, lodgepole pine, and lodgepole pine ground-fire pathways.
Conceptual models were presented showing how perturbations by fire, insect epidemics, and disease could interact to influence succession and shape the subalpine landscape. The subalpine forest changes through time to facilitate different types of disturbance that have varying effects on succession. In the continued suppression of fire, species and age class diversity will be reduced and disturbances may occur that are larger and more intense than those that have occurred historically.
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Post-fire Behaviour of Innovative Shear Connection for Steel-Concrete Composite StructuresMashiri, F.R., Mirza, O., Canuto, C., Lam, Dennis 08 December 2016 (has links)
Yes / Steel-concrete composite structures are commonly used in buildings and bridges because it takes advantage of tensile strength of steel and compressive strength of concrete. The two components are often secured by shear connectors such as headed studs to prevent slippage and to maintain composite action. In spite of its popularity, very little research was conducted on steel-concrete composites particularly on headed stud shear connectors in regards to its post-fire behaviour. This research investigates the post-fire behaviour of innovative shear connectors for composite steel and concrete. Three type of connectors were investigated. They are headed stud shear connectors, Blind Bolt 1 and Blind Bolt 2 blind bolts. Push-out test experimental studies were conducted to look at the behaviour and failure modes for each connector. Eighteen push tests were conducted according to Eurocode 4. The push test specimens were tested under ambient temperatures and post fire condition of 200˚C, 400˚C and 600˚C. The results in ambient temperature are used to derive the residual strength of shear connectors after exposing to fire. Findings from this research will provide fundamental background in designing steel-concrete composites where there is danger of fire exposure.
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Postfire regeneration of mountain fynbos by resprouting : a comparison of species with different life history typesMarais, Karen E. 12 1900 (has links)
Thesis (MScConEcol)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The fire-prone mediterranean-type climate regions of the world are immensely biodiverse.
Changes in fire frequency due to anthropogenic ignitions and climate change are one of the
factors threatening the plant diversity of these regions. Many postfire regeneration studies
have focused on seedling recruitment, whereas much can still be learned about regeneration
through resprouting. This project focused on resprouters after a fire and assessed if there
are differences between the obligate (OS) and facultative (FS) resprouting life history types.
OS species have to resprout after fire, as their seeds are not fire resistant and seedling
recruitment takes place in fire-free periods, whereas FS species have the ability to resprout
and recruit seedlings after a fire.
My analyses found a significant difference in postfire resprout success between OS
species and FS species, supporting the division of woody resprouting shrubs into these two
life history types. OS species had minimal fire-related mortality and this was related to their
ability to resprout early and vigorously after fire. OS species had no postfire mortality, which
points to traits that enable them to endure the hot and dry summer months. The FS species
varied in their response to fire and had greater fire induced mortality than the OS species.
Postfire mortality (post-sprouting) was also greater compared to OS species, especially
towards the end of the long dry summer suggesting a link to water stress.
A postfire seedling survey of target FS, OS and non-sprouters (NS), revealed that
NS species had seedling/adult ratios that were orders of magnitude higher ranging between
40-200 seedlings per adult against less than 1-10 seedlings per adults for FS, with OS
species recruiting no seedlings directly postfire, as is consistent with their life history type.
Although the NS species do not sprout and the FS species had some mortality, the
population was at or above replacement two-year postfire on account of seedling
recruitment. OS species maintained their pre-fire population by successfully resprouting and
by experiencing almost no postfire mortality. These results provide strong justification for
grouping woody resprouters into OS and FS species in future studies seeking to understand
the underlying differences in postfire recovery.
Postfire flowering phenology was also observed during the two year study period.
Geophytes, mostly belonging to the Iridaceae and Orchidaceae were overrepresented within
the first year postfire, many displaying fire-stimulated flowering. This suggests that some
geophytes limit their reproductive cycle to the immediate postfire environment, when
nutrients and light are abundant. Smaller resprouting shrubs generally flowered earlier than larger resprouting shrubs. Many non-sprouting shrubs did not reach maturity within the study
period and those that did mostly belonged to the Fabaceae and Asteraceae families. This study added 71 species to the existing Paarl Mountain species list, including eight new red
listed species, highlighting the importance of early postfire field surveys. / AFRIKAANSE OPSOMMING: Veldbrande is ‘n natuurlike verskynsel in die meditereense klimaatstreke van die wereld.
Hierdie areas is ook bekend vir hulle ryk biodiversiteit. Veranderinge in die vuur frekwensie
as gevolg van klimaatsverandering en veldbrande wat deur mense veroorsaak word, bedreig
die plantdiversiteit van hierdie streke. Vorige veldbrandstudies het meestal gefokus op
saailinge en daar bestaan ‘n groot leemte om regenerasie deur herspruiting beter te
verstaan. Hierdie navorsingsprojek fokus op herspruiting van fynbos plante as ‘n
oorlewingstrategie na ‘n veldbrand. Spesifiek word daar gekyk na verskille tussen verpligte
(VH) en nie-verpligte (fakultatiewe) herspruiters (FH). VH spesies moet herspruit na vuur om
hulle populasie stabiel te hou, aangesien hulle saad nie vuurbestand is nie. FH spesies het
die vermoë om te herspruit sowel as saailinge te werf na ‘n brand.
Die studie bevindinge dui op betekenisvolle verskille tussen hierdie twee
lewensgeskiedenistipes en regverdig die groepering van houtagtige herspruiter spesies as
VH of FH. VH het minimale mortaliteit getoon na die veldbrand. Bykans alle plante het
vinnig en kragtig herspruit. VH besit ook eienskappe wat hulle in staat stel om die warm,
droeë somers te oorleef. Die oorlewing van FH was wisselvallig, met mortaliteit as gevolg
van direkte vuurskade en verdere mortaliteit gedurende die lang somermaande, moonlik as
gevolg van water stress.
‘n Saailingstudie van VH, FH en ook nie-spruiters (NS) het getoon dat die
saailing/volwasse verhoudings van NS ordes hoër is as die van FH. VH het geen saailinge
direk na die vuur geproduseer nie. Twee jaar na die vuur was FH en NS saailing getalle
steeds heelwat meer as die aantal volwasse plante wat dood is in die veldbrand. VH het hul
populasie stabiliteit gehandhaaf deurdat alle volwasse plante suksesvol herspruit het.
Hierdie bevindinge regverdig die verdeling van herspruitende fynbos spesies as VH of FH.
Verdere studies is belangrik om die onderliggende ekofisiologiese verskille tussen die twee
lewensgeskiedenistipes beter te verstaan.
Die blompatrone van verskillende spesies is ook aangeteken tydens die tweejaar
studieperiode. Bolplante, veral in die iris- (Iridaceae) en orgidee (Orchidaceae) families het
oorheers gedurende die eerste jaar na die brand, aanduidend van ‘n vuur-gestimuleerde
blompatroon. Sommige bolplante mag hul voorplantingssiklus beperk tot die periode direk na
veldbrand, terwyl daar genoeg lig is en die grond verryk is met voedingsstowwe. Kleiner
herspruitende struike het in die algemeen vroeër geblom as groter struike. Nieherspruitende
struike het meestal nie seksuele volwassenheid bereik binne twee jaar na die
veldbrand nie, buiten sommige in die ertjie- (Fabaceae) en asterfamilies (Asteraceae). Die studie het 71 nuwe spesies tot die bestaande Paarlberg spesielys gevoeg, waarvan agt
rooidataspesies was, wat die waarde van plantopnames direk na ‘n veldbrand beklemtoon.
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Historique et caractéristiques écologiques des îlots résiduels après feu en forêt boréale mixte / Assessing the potential of post-fire residual patches as sanctuaries for biodiversity conservation in the boreal forestOuarmim, Samira 17 December 2013 (has links)
Le feu est la principale perturbation en forêt boréale mixte. La sévérité des feux n'est pas spatialement homogène et épargne souvent partiellement ou entièrement des parties de la forêt appelées îlots résiduels. Ces îlots forestiers résiduels après feux sont étudiés depuis de nombreuses années, et ces études se sont surtout intéressées aux facteurs déterminant leur occurrence à l'échelle du paysage. Cependant, les travaux réalisés en Fennoscandinavie et aux États-Unis ont révélé la présence de peuplements forestiers (appelés refuges) ayant la capacité de se maintenir dans le territoire pendant plusieurs millénaires. L'objectif principal de cette thèse était de caractériser la dynamique temporelle et la structuration d'îlots forestiers localisés au sein de la forêt boréale mixte de l'est du Canada. Treize îlots forestiers qui ont échappé au dernier feu ont été échantillonnés. Des carottes de sols ont été extraites dans chacun des sites pour réaliser des analyses paléoécologiques (charbons et macrorestes). Les caractéristiques stationnelles de chaque site ont été échantillonnées pour déterminer si les refuges se distinguent des autres îlots résiduels. La charge en combustible des îlots a également été mesurée. Les données ont également servi à alimenter des modèles numériques de comportement du feu (Fire Behavior Prediction System, BehavePlus, FlamMap3) qui ont été utilisés afin de déterminer les caractéristiques stationnelles qui permettent aux refuges d'échapper au feu de façon récurrente. Les résultats ont mis en évidence l'existence de deux types d'îlots résiduels en forêt boréale mixte : les refuges et les autres îlots résiduels. Les refuges sont moins susceptibles au feu comparativement aux îlots résiduels qui ont échappé uniquement au dernier feu, probablement de façon fortuite. Les refuges ont en revanche la capacité de persister dans le paysage forestier durant plusieurs millénaires, ne brûlant uniquement durant des feux particulièrement sévères. Les analyses macrofossiles des refuges soulignent des changements majeurs au sein de la végétation locale, avec comme événement remarquable le passage de formations dominées par Larix laricina/Picea sp. vers des formations dominées par Abies balsamea/Thuja occidentalis. Ce changement de végétation s'est produit à différentes périodes selon les sites, soulignant un processus endogène dans cette transformation de la végétation. Le développement de Larix laricina s'est accompagné dans certains assemblages macrofossiles de taxons typiques de milieux humides (tels que les characées). L'importante couche de matière organique qui caractérise les refuges semble entraver le développement d'espèces de début de succession telles que Betula papyrifera et Populus tremuloïdes. Les îlots refuges doivent leur persistance dans le paysage forestier à un certain nombre de facteurs biotiques et abiotiques qui limitent le passage du feu. Les résultats issus des simulations du comportement du feu, suggèrent un rôle mineur des coupe-feu (lacs, tourbières, et monticules rocheux essentiellement), de la charge en combustible et de la topographie dans l'occurrence des refuges. L'humidité semble être le seul facteur déterminant leur développement au sein de la mosaïque paysagère. Les refuges se mettent en place au sein de faibles dépressions humides qui favorisent l'accumulation de la matière organique. La structure des refuges et des autres îlots résiduels révèle deux principales caractéristiques permettant de les distinguer sur le terrain : le diamètre moyen des arbres et l'épaisseur de la matière organique. Les arbres des refuges ont un plus petit diamètre que ceux des autres îlots résiduels. L'importante épaisseur de la matière organique des refuges affecte négativement la croissance des arbres. Ces caractéristiques pourront être utilisées comme outils d'aide à la décision dans les stratégies d'aménagement forestier. / Fire is the main natural disturbance shaping boreal forest landscapes. In North American boreal ecosystems, wildfires contribute to the creation of a complex mosaic of stands of varying age, composition, and structure, within which other disturbances and processes can interact. A burned area usually includes tree patches that partially or entirely escaped fire, called post-fire residual patches. The spatially occurrence of post-fire residual patches has been extensively described. However, the presence of fire refuges has been reported in Fennoscandia and in United-States, which can escape fire for several millennia. The aim of this study was to characterize temporal dynamics in post fire residual patches in mixedwood boreal forest of eastern Canada. The analyses concern the reconstruction of fire and forest dynamics history though Holocene and identify characteristics features of these patches. This research aimed to contribute significantly to the objectives of ecosystemic management to preserve biological diversity in the forest mosaics.Thirteen post-fire residual patches which escaped the last fire have been sampled. At each stand, cores and monoliths were extracted for paleoecological analyses. The reconstitution of fire history and forest dynamics were studies by using macroscopic charcoals and macroremains. The characteristics features of stands were also sampled, to differentiate fire refuges from other post-fire residual patches. The fuel load was also measured, and all these data were used as inputs for fire behavior modeling (Fire Behavior Prediction System, BehavePlus, FlamMap3), to identify stand characteristics prevent fire refuges to burn in comparison with other residual stands and forest matrix.The results showed the presence in the landscaped of two types of post-fire residual patches in mixedwood boreal forest: fire refuges and other post-fire residual patches. The fire refuges present less fire susceptibility than other post-fire residual patches, which escape only the last fire probably by chance. On the other hand, fire refuges can persist in the landscape for several millennia, burning in the most severe fires. The forest dynamics reconstruction in fire refuges, highlight major shift in the vegetation from Larix laricina/Picea sp. to late successional species Abies balsamea/Thuja occidentalis. Occuring at all stands, but at different periods of Holocene, these changes can be attributed to internal processes. The presence of Larix laricina was associated to the occurrence of aquatic taxa (e.g. Characear). The late successional species (Abies balsamea/Thuja occidentalis) can persist in the landscape for several centuries due to moisture conditions. The thickness of organic matter recorded in fire refuges seems to inhibit the recruitment of early successional species such as Betula papyrifera et Populus tremuloïdes.The fire refuges owe their persistence in the landscape to abiotoc and biotic factors that limit fire occurrence. Then results obtained from fire behavior simulations, suggest a minor role of fire breaks (lakes, rocks), fuel load and topography in persistence of fire refuges. Local moisture condition seems to be key factor in their occurrence in the landscape. The fire refuges occur likely in depressions, which favor organic matter accumulation. The structure of fire refuges and other residual patches revealed two main characteristics, which distinguish between the two types of residual patches: Mean diameter of trees and thickness of organic matter. The trees of fire refuges present smaller tree diameter than other post-fire residual patches. The thickness of organic matter accumulation in fire refuges affects negatively the growth of trees. These features can be used as tools for decision support in forest management strategies.
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Developing fixed-point photography methodologies for assessing post-fire mountain fynbos vegetation succession as a tool for biodiversity managementAlkalei, Osama January 2020 (has links)
Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol) / Areas of high biodiversity and complex species assemblages are often difficult to manage and to set up meaningful monitoring and evaluations programmes. Mountain Fynbos is such an ecosystem and in the Cape of Good Hope (part of the Table Mountain National Park) plant biodiversity over the last five decades has been in decline. The reasons are difficult to speculate since large herbivores, altered fire regimes and even climate change could be contributors to this decline which has been quantified using fixed quadrats and standard cover-abundance estimates based on a Braun-Blanquet methodology. To provide more detailed data that has more resolution in terms of identifying ecological processes, Fixed-Point Repeat Photography has been presented as a management “solution”. However, photography remains a difficult method to standardize subjects and has certain operational limitations.
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