| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 5.88 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
O presente trabalho pretende testar a hipĂłtese de que a resistĂȘncia dos azinhais
ao fogo depende da distribuição de combustĂveis ao longo do gradiente exterior â
interior dos azinhais (orlas). Com base na descrição quantitativa do complexo
combustĂvel, pretende ainda criar modelos de combustĂvel para o azinhal e analisar o
comportamento do fogo potencial, de acordo com os parĂąmetros do modelo de
propagação do fogo de Rothermel (1972) que integra o Software BehavePlus (Andrews
et al., 2004).
Este trabalho iniciou-se em Abril 2007 e foi realizado na regiĂŁo Este do Parque
Natural de Montesinho (Distrito e Concelho de Bragança), onde foi feita a identificação
e descrição de todas as manchas de azinhal envolvendo os incĂȘndios ocorridos nesta
ĂĄrea com base em cartografia de azinhais e de fogos florestais.
Ao longo das orlas de doze manchas seleccionadas quantificaram-se parĂąmetros
estruturais dos vĂĄrios estratos do complexo combustĂvel (herbĂĄceo, arbustivo e arbĂłreo),
e ainda parùmetros ambientais e de relevo, necessårios para a criação dos modelos de
combustĂvel para utilização com o modelo de propagação do fogo de Rothermel.
Desenvolvidos os modelos e para podermos comparar inflamabilidades entre
complexos de combustĂveis, simulamos o comportamento do fogo em BehavePlus para
os modelos de combustĂvel de acordo com a sua distribuição ao longo do gradiente
exterior â interior dos azinhais. Os modelos especĂficos desenvolvidos reflectem o
conjunto de condiçÔes, no que diz respeito ao combustĂvel, que Ă© possĂvel encontrar nos
bosques de azinhal, ao longo do gradiente exterior â interior dos bosques e ainda no
exterior do mesmo.
Como resultados, observou-se que o fogo simulado tem uma tendĂȘncia para
decrescer em termos de velocidade de propagação, intensidade da frente das chamas, e
comprimento da chama ao passar de ĂĄreas dominadas por matos para o azinhal. Esta
alteração do comportamento do fogo nas orlas parece indicar a possibilidade de o fogo
se extinguir naturalmente quando entra em contacto com os azinhais. Estas alteraçÔes
do comportamento do fogo parecem estar associadas a alteraçÔes da estrutura destas
orlas, nĂŁo obstante outros factores poderĂŁo igualmente contribuir para este fenĂłmeno.
The current work intends to test the hypothesis that the resistance of the holmoak patches to fire depends on the distribution of fuel in the exterior-interior gradient (edges). Based in a quantitative description of the compound fuel, also intend to create fuel models to the holm-oak and analyze the behavior of the potential fire, according to the parameters of spread model of Rothermelâs fire (1972) a part of the BehavePlus software (Andrews et al., 2004). This work began in April 2007 and was executed in the East region of the Natural Park of Montesinho (District and municipality of Bragança), where we carried out the identification and description of all the holm-oak patches involving fires occurred in the area based on holm-oak and forest fires mapps. We have quantified structural parameters of the several strata of the fuel complex (herbaceous, shrubby and arboreous), and also environmental and relief parameters needful to the creation of fuel models to use with spread model of Rothermelâs fire in twelve selected patches. In order to compare models, we simulated the fire behavior in BehavePlus according to its distribution in the exterior-interior gradient of the holm-oak patches. The particular models developed here reflect the aggregation of conditions, in terms of fuel, found in the holm-oak patches, in the exterior - interior gradient of woods and also in its exterior. As results, we noticed that the simulated fire has a tendency to decrease in terms of surface rate of spread, fireline intensity and flame length passing from shrub dominated areas to the interior of woods. This variation in fire behavior on the edges seems to indicate the possibility that fire can be extinguish naturally when contact the woods. These changes of fire behavior seem to be associated to the modifications of vegetation structure in these edges, despite other factors that contribute to this phenomenon.
The current work intends to test the hypothesis that the resistance of the holmoak patches to fire depends on the distribution of fuel in the exterior-interior gradient (edges). Based in a quantitative description of the compound fuel, also intend to create fuel models to the holm-oak and analyze the behavior of the potential fire, according to the parameters of spread model of Rothermelâs fire (1972) a part of the BehavePlus software (Andrews et al., 2004). This work began in April 2007 and was executed in the East region of the Natural Park of Montesinho (District and municipality of Bragança), where we carried out the identification and description of all the holm-oak patches involving fires occurred in the area based on holm-oak and forest fires mapps. We have quantified structural parameters of the several strata of the fuel complex (herbaceous, shrubby and arboreous), and also environmental and relief parameters needful to the creation of fuel models to use with spread model of Rothermelâs fire in twelve selected patches. In order to compare models, we simulated the fire behavior in BehavePlus according to its distribution in the exterior-interior gradient of the holm-oak patches. The particular models developed here reflect the aggregation of conditions, in terms of fuel, found in the holm-oak patches, in the exterior - interior gradient of woods and also in its exterior. As results, we noticed that the simulated fire has a tendency to decrease in terms of surface rate of spread, fireline intensity and flame length passing from shrub dominated areas to the interior of woods. This variation in fire behavior on the edges seems to indicate the possibility that fire can be extinguish naturally when contact the woods. These changes of fire behavior seem to be associated to the modifications of vegetation structure in these edges, despite other factors that contribute to this phenomenon.
Description
Keywords
Azinhais Comportamento do fogo Modelos de combustĂvel Modelos de comportamento do fogo Sistema BehavePlus GestĂŁo de combustĂveis