Fire regimes and forest structure in the Sierra Madre Occidental, Durango, Mexico
Frequent, low-intensity fire is a key disturbance agent in the long-needled pine forests of western North America, but little is known about the fire ecology of the Mexican forests which have been least affected by fire exclusion. We compared fire disturbance history and forest structure at four unh...
| Main Authors: | , |
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| Formato: | Online |
| Idioma: | spa |
| Publicado: |
Instituto de Ecología, A.C.
1997
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| Acceso en liña: | https://abm.ojs.inecol.mx/index.php/abm/article/view/791 |
| _version_ | 1799771207332003840 |
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| author | Fule, Peter Z. Covington, W. Wallace |
| author_facet | Fule, Peter Z. Covington, W. Wallace |
| author_sort | Fule, Peter Z. |
| collection | ABM |
| description | Frequent, low-intensity fire is a key disturbance agent in the long-needled pine forests of western North America, but little is known about the fire ecology of the Mexican forests which have been least affected by fire exclusion. We compared fire disturbance history and forest structure at four unharvested or lightly-harvested study sites differing in recent fire history. Frequent, low-intensity fires, recurring between 4 to 5 years for all fires and 6 to 9 years for widespread fires, characterized all the sites until the initiation of fire exclusion in the mid-twentieth century at three of the four sites. Although most fires in the study area are ascribed to human ignitions, evidence of both lightning and human-caused burning was observed on the study sites. A possible connection between fire occurrence and climate was indicated by a correspondence between regional fire years and positive extremes of the Southern Oscillation index, which is associated with cold/dry weather conditions. Forest ecosystem structures differed in ways consistent with the thinning and fuel consuming effects of fire. Two sites with extended fire exclusion were characterized by relatively dense stands of smaller and younger trees, high dead woody biomass loading, and deeper forest floors. In contrast, a site which had burned following a 29-year fire exclusion period, and the final site where frequent fires had continued up to the present, were both relatively open forests dominated by larger trees. The recently burned sites had lower dead woody biomass loading, especially of rotten woody fuels, and more shallow duff layers. The high regeneration density but low overstory density at the recently burned sites is also consistent with the thinning effect of low-intensity fire. Long-term management and conservation strategies for these forests should recognize the historic role of fire disturbance as well as the potential for changes in fire intensity and ecological effects following extended fire exclusion. |
| format | Online |
| id | oai:oai.abm.ojs.inecol.mx:article-791 |
| institution | Acta Botanica Mexicana |
| language | spa |
| publishDate | 1997 |
| publisher | Instituto de Ecología, A.C. |
| record_format | ojs |
| spelling | oai:oai.abm.ojs.inecol.mx:article-7912022-12-24T05:46:06Z Fire regimes and forest structure in the Sierra Madre Occidental, Durango, Mexico Fire regimes and forest structure in the Sierra Madre Occidental, Durango, Mexico Fule, Peter Z. Covington, W. Wallace Frequent, low-intensity fire is a key disturbance agent in the long-needled pine forests of western North America, but little is known about the fire ecology of the Mexican forests which have been least affected by fire exclusion. We compared fire disturbance history and forest structure at four unharvested or lightly-harvested study sites differing in recent fire history. Frequent, low-intensity fires, recurring between 4 to 5 years for all fires and 6 to 9 years for widespread fires, characterized all the sites until the initiation of fire exclusion in the mid-twentieth century at three of the four sites. Although most fires in the study area are ascribed to human ignitions, evidence of both lightning and human-caused burning was observed on the study sites. A possible connection between fire occurrence and climate was indicated by a correspondence between regional fire years and positive extremes of the Southern Oscillation index, which is associated with cold/dry weather conditions. Forest ecosystem structures differed in ways consistent with the thinning and fuel consuming effects of fire. Two sites with extended fire exclusion were characterized by relatively dense stands of smaller and younger trees, high dead woody biomass loading, and deeper forest floors. In contrast, a site which had burned following a 29-year fire exclusion period, and the final site where frequent fires had continued up to the present, were both relatively open forests dominated by larger trees. The recently burned sites had lower dead woody biomass loading, especially of rotten woody fuels, and more shallow duff layers. The high regeneration density but low overstory density at the recently burned sites is also consistent with the thinning effect of low-intensity fire. Long-term management and conservation strategies for these forests should recognize the historic role of fire disturbance as well as the potential for changes in fire intensity and ecological effects following extended fire exclusion. El fuego frecuente de baja intensidad es un agente clave de disturbio en los bosques de pinos de hojas largas del occidente de Norteamérica; sin embargo, se conoce poco de la ecología del fuego en los bosques mexicanos que han sido menos afectados por la exclusión del fuego. Comparamos la secuencia de disturbio causado por fuego y la estructura forestal de cuatro sitios, poco o no explotados, que varían en su reciente historial de fuegos. Los frecuentes incendios de baja intensidad, que se presentaron periódicamente cada 4 a 5 años, si se toman en cuenta todos los incendios, y cada 6 a 9 años para el caso de los incendios extensos, caracterizaron todos los sitios hasta el inicio de la exclusión de fuego a mediados del siglo XX en tres de las cuatro parcelas de estudio. Aunque se considera que la mayoría de los incendios en el área son de origen humano, en los sitios de referencia se observaron evidencias de igniciones causadas tanto por las descargas eléctricas, como por el hombre. Una posible conexión entre la incidencia de los incendios y el clima quedó señalada por la correlación encontrada entre los años con incendios regionales y los extremos positivos del índice de oscilación meridional, asociados con condiciones de clima frío y seco. Las estructuras del ecosistema forestal diferían de acuerdo con los efectos del aclareo de árboles y del consumo de material combustible. Dos sitios con una larga exclusión de incendios se caracterizaron por masas relativamente densas de árboles más pequeños y jóvenes, altas cantidades de material combustible, y capas de humus más profundas. En contraste, tanto en la parcela que se quemó después de un período de exclusión de fuego de 29 años, como también en el último sitio donde los incendios frecuentes han continuado hasta el presente, se registraron bosques relativamente abiertos dominados por árboles más grandes y maduros. Las áreas de muestreo recientemente quemadas tenían menos material combustible, especialmente de madera podrida, y capas de humus menos profundas. La gran cantidad de renuevos en combinación con la baja densidad del estrato superior de los sitios recientemente quemados es también consistente con el efecto de aclareo de los incendios de poca intensidad. Las estrategias para la conservación y el manejo a largo plazo de estos bosques deben reconocer el papel histórico del disturbio causado por el fuego, así como el potencial de cambios en la intensidad de los incendios y los efectos ecológicos de una larga exclusión de fuego. Instituto de Ecología, A.C. 1997-10-01 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion artículo evaluado por pares application/pdf https://abm.ojs.inecol.mx/index.php/abm/article/view/791 10.21829/abm41.1997.791 Acta Botanica Mexicana; No. 41 (1997); 43-79 Acta Botanica Mexicana; Núm. 41 (1997); 43-79 2448-7589 0187-7151 spa https://abm.ojs.inecol.mx/index.php/abm/article/view/791/957 Derechos de autor 2016 Acta Botanica Mexicana https://creativecommons.org/licenses/by-nc/4.0 |
| spellingShingle | Fule, Peter Z. Covington, W. Wallace Fire regimes and forest structure in the Sierra Madre Occidental, Durango, Mexico |
| title | Fire regimes and forest structure in the Sierra Madre Occidental, Durango, Mexico |
| title_full | Fire regimes and forest structure in the Sierra Madre Occidental, Durango, Mexico |
| title_fullStr | Fire regimes and forest structure in the Sierra Madre Occidental, Durango, Mexico |
| title_full_unstemmed | Fire regimes and forest structure in the Sierra Madre Occidental, Durango, Mexico |
| title_short | Fire regimes and forest structure in the Sierra Madre Occidental, Durango, Mexico |
| title_sort | fire regimes and forest structure in the sierra madre occidental, durango, mexico |
| url | https://abm.ojs.inecol.mx/index.php/abm/article/view/791 |
| work_keys_str_mv | AT fulepeterz fireregimesandforeststructureinthesierramadreoccidentaldurangomexico AT covingtonwwallace fireregimesandforeststructureinthesierramadreoccidentaldurangomexico |
