Publication: FACTORES NATURALES QUE INFUYEN EN LA INFLAMABILIDAD DE ESPECIES FORESTALES EXÓTICAS Y NATIVAS: CASO DE ESTUDIO, RESERVA NACIONAL LAGO PEÑUELAS, VALPARAÍSO
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Date
2019-10
Authors
HERNÁNDEZ VALENCIA, CARLA DANIELA
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Abstract
La región de Valparaíso ha sido constantemente amenazada por incendios forestales, afectando a
especies forestales nativas y exóticas. Su ecosistema de tipo mediterráneo bajo una clara
estacionalidad (muy seco en verano) y el factor humano proporcionan las condiciones necesarias para
el inicio y la propagación del fuego. Existen también factores naturales que influyen en la
inflamabilidad de las especies forestales, siendo los terpenos los mas estudiados. Cuando las hojas de
las especies forestales están sometidas a altas temperaturas, antes de la fase de llama, inducen
fácilmente a la evaporación de terpenos (altamente inflamables) contenidos al interior de las hojas
contribuyendo al encendido y propagación del fuego en un incendio forestal.
El objetivo principal es la determinación de terpenos, contenido de humedad e inflamabilidad de las
hojas de especies nativas (Quillaja saponaria y Cryptocarya alba) y exóticas (Pinus radiata,
Eucalyptus globulus y Acacia dealbata) recolectadas durante la época de verano 2019 en la Reserva
Nacional Lago Peñuelas, Valparaíso. Los objetivos específicos son 1)determinación del grado de
inflamabilidad de las hojas de especies exóticas/nativas seleccionadas usando el instrumento
epirradiador, considerando la ignitabilidad y sostenibilidad, 2)caracterización química de las hojas de
especies exóticas/nativas seleccionadas, 3)determinación de terpenos contenidos en las hojas de
especies exóticas/nativas, usando extracción soxhlet y análisis por Cromatografía Gaseosa acoplada
a Espectrometría de Masas y 4)estudiar el efecto de los terpenos y contenido de humedad sobre la
inflamabilidad utilizando análisis de varianza ANOVA.
Los resultados muestran presencia de sesquiterpenos para la mayoría de las especies analizadas. Los
principales compuestos identificados fueron para: P. radiata: (E)-β-cariofileno y germacreno D, E.
globulus: aloaromadendreno y aromadendreno, C. alba: α-bergamoteno y germacreno D y para Q.
saponaria: aromadendreno y aloaromadendreno. Por otro lado, los tiempos de ignición fueron: E.
globulus: 3,98 s (grado de inflamabilidad 5, extremadamente inflamable), C. alba: 6,85 s (grado de
inflamabilidad 5, extremadamente inflamable), A. dealbata: 9,64 s (grado de inflamabilidad 5,
extremadamente inflamable), P. radiata: 19,64 s (grado de inflamabilidad 3, inflamable) y Q.
saponaria: 20,99 s (grado de inflamabilidad 3, inflamable).
La presencia de estos compuestos volátiles se relaciona positivamente con la inflamabilidad, debido
a que todas las especies resultaron ser inflamables, según la tabla propuesta por Valette (1990). El
principal impacto de este trabajo es contribuir con información respecto a factores naturales y su
relación con la inflamabilidad del follaje de especies nativas, dado que no existen estudios actuales
que describan su relación, considerando que Chile es un país vulnerable a incendios forestales. Esta
información proporciona potenciales indicadores de riesgos que plantea una especie forestal en
épocas de incendios forestales, contribuyendo a orientar las reforestaciones para que en un futuro las
formaciones de bosques mediterráneos sean menos susceptibles a estos y, por lo tanto, reducir el daño
causado por los incendios forestales.
Valparaíso region has been constantly threatened by wildland fires, affecting native and exotic forest species. Its mediterranean-type ecosystem under a clear seasonality (very dry in summer) and the human factor provide the necessary conditions for the onset and spread of fire. There are also natural factors that influence the flammability of forest species, terpenes being the most studied. When the leaves of the forest species are subjected to high temperatures, before the flame phase, they easily induce the evaporation of highly flammable terpenes contained inside the leaves contributing to the ignition and propagation of the forest fire. The main objective of this investigation is the determination of terpenes, moisture content and flammability of the leaves of native species (Quillaja saponaria and Cryptocarya alba) and exotic (Pinus radiata, Eucalyptus globulus and Acacia dealbata), collected during the summer of 2019 in the Reserva Nacional Lago Peñuelas, Valparaíso. The specific objectives are: 1) determination of the flammability degree of the leaves in the selected exotic and native species using an epirradiator, considering ignitability and sustainability, 2) chemical characterization of the leaves in the selected exotic and native species, 3) determination of the terpene content of the leaves in the exotic and native species, using soxhlet extraction and analysis by Gas Chromatography coupled to Mass Spectrometry, 4) study the effect of terpenes and moisture content on flammability using ANOVA analysis of variance. The results show the presence of sesquiterpenes in the most of the species analyzed. The main compounds identified were: P. radiata: (E) -β-caryophylene and germacrene D, E. globulus: aloaromadendrene and aromadendrene, C. alba: α-bergamotene and germacrene D and Q. saponaria: aromadendrene and aloaromadendrene. On the other hand, the ignition times were: E. globulus: 3.98 s (flammability grade 5, extremely flammable), C. alba: 6.85 s (flammability grade 5, extremely flammable), A. dealbata: 9.64 s (flammability grade 5, extremely flammable), P. radiata: 19.64 s (flammability grade 3, flammable) and Q. saponaria: 20.99 s (flammability grade 3, flammable). The presence of these volatile compounds relates positively with the flammability, because all the species turned out to be flammable in different degrees, according to the table proposed by Valette (1990). This investigation contributes to information regarding natural factors and their relationship with the flammability of the foliage of native species, since there are no current studies describing their relationship, considering that Chile is a country vulnerable to wildland fires. This information provides potential indicators for the risk posed by a forest species in times of wildland fires, contributing to orienting reforestation so that in the future mediterranean forest formations are less susceptible to them and, therefore, reducing the damage caused by wildland fire.
Valparaíso region has been constantly threatened by wildland fires, affecting native and exotic forest species. Its mediterranean-type ecosystem under a clear seasonality (very dry in summer) and the human factor provide the necessary conditions for the onset and spread of fire. There are also natural factors that influence the flammability of forest species, terpenes being the most studied. When the leaves of the forest species are subjected to high temperatures, before the flame phase, they easily induce the evaporation of highly flammable terpenes contained inside the leaves contributing to the ignition and propagation of the forest fire. The main objective of this investigation is the determination of terpenes, moisture content and flammability of the leaves of native species (Quillaja saponaria and Cryptocarya alba) and exotic (Pinus radiata, Eucalyptus globulus and Acacia dealbata), collected during the summer of 2019 in the Reserva Nacional Lago Peñuelas, Valparaíso. The specific objectives are: 1) determination of the flammability degree of the leaves in the selected exotic and native species using an epirradiator, considering ignitability and sustainability, 2) chemical characterization of the leaves in the selected exotic and native species, 3) determination of the terpene content of the leaves in the exotic and native species, using soxhlet extraction and analysis by Gas Chromatography coupled to Mass Spectrometry, 4) study the effect of terpenes and moisture content on flammability using ANOVA analysis of variance. The results show the presence of sesquiterpenes in the most of the species analyzed. The main compounds identified were: P. radiata: (E) -β-caryophylene and germacrene D, E. globulus: aloaromadendrene and aromadendrene, C. alba: α-bergamotene and germacrene D and Q. saponaria: aromadendrene and aloaromadendrene. On the other hand, the ignition times were: E. globulus: 3.98 s (flammability grade 5, extremely flammable), C. alba: 6.85 s (flammability grade 5, extremely flammable), A. dealbata: 9.64 s (flammability grade 5, extremely flammable), P. radiata: 19.64 s (flammability grade 3, flammable) and Q. saponaria: 20.99 s (flammability grade 3, flammable). The presence of these volatile compounds relates positively with the flammability, because all the species turned out to be flammable in different degrees, according to the table proposed by Valette (1990). This investigation contributes to information regarding natural factors and their relationship with the flammability of the foliage of native species, since there are no current studies describing their relationship, considering that Chile is a country vulnerable to wildland fires. This information provides potential indicators for the risk posed by a forest species in times of wildland fires, contributing to orienting reforestation so that in the future mediterranean forest formations are less susceptible to them and, therefore, reducing the damage caused by wildland fire.
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Keywords
TERPENOS , INFLAMABILIDAD