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Integrating ecological principles in fire management: Impact of fire fighting chemicals on soil-plant systems from temperate humid zone
Forest Ecology and Management 234S (2006) S265
Abstract
Integrating ecological principles in fire management: Impact of fire fighting chemicals on soil-plant systems from temperate humid zone A. Couto-Va´zquez, J. Mahı´a, M. Dı´az-Ravin˜a, T. Carballas, S.J. Gonza´lez-Prieto Instituto de Investigaciones Agrobiolo´gicas de Galicia (CSIC), Campus Universitario Sur, Apartado 122, E-15780 Santiago de Compostela, Spain
Keywords: Prescribed fires; Fire fighting agents; Soil properties; Plant growth
Nowadays fire fighting chemicals are being used as water additives to combat wildfires and control prescribed burns for habitat management of forest ecosystems located in Mediterranean countries. However, information on their environmental impact such as the effects of these compounds on both soil (physical, chemical and biological properties) and vegetation is not available. In the present study, the shortand medium-term influence of three different fire fighting agents on burnt soil properties and vegetation cover restoration was examined under field conditions. The study was performed in a heathland on a Humic Cambisol, located in the temperate humid region (Galicia, NW Spain), and subjected to a prescribed burnt. The recovery of the burnt area was studied following the growing of pine trees planted in the plots. The following situations were considered: (i) unburnt soil (US); (ii) burnt soil added with water (BS); (iii) burnt soil added with a foaming agent (BS + Fo); (iv) burnt soil with the fire retardant Firesorb (BS + Fi); and (v) burnt soil added with ammonium polyphosphate (BS + Ap). Soil samples were collected at different times during 1 year (0, 1, 30, 90 and 365 days) and chemical and biochemical properties (pH, total C, total N, inorganic N, available P, d 15N, soluble carbohydrates,
DOI: 10.1016/j.foreco.2006.08.294 E-mail address: [email protected] (T. Carballas).
microbial biomass C and urease and (-glucosidase activities) as well as the growth of the pines planted were measured. The results showed that initially the soil was affected by the prescribed fire and that it tended to recover with time; however, 1 year after the prescribed fire a significant fire effect on most analyzed properties (total C, total N, d 15N, soluble carbohydrates, microbial biomass C and enzyme activities) was observed. The data also indicated that, compared to the burnt treatment, the ammonium polyphosphate was the fire fighting agent most affecting soil properties and pine growth. Initially, ammonium polyphosphate increased notably inorganic N, mainly NH4+-N, available P and soil pH but, except for available P, this effect disappeared at the end of the experiment. A negative effect of ammonium polyphosphate on soil enzyme activities was still observed 1 year after the prescribed fire. The pine growth in plots with ammonium polyphosphate also showed a different trend than that in the other plots. Initially the growth was lower than that presented by the unburnt soil and similar to that observed in the other burned soils; but, after 3 months the growth increased notably reaching after 1 year values even higher than those observed in the unburnt soil.
Abstract
Integrating ecological principles in fire management: Impact of fire fighting chemicals on soil-plant systems from temperate humid zone A. Couto-Va´zquez, J. Mahı´a, M. Dı´az-Ravin˜a, T. Carballas, S.J. Gonza´lez-Prieto Instituto de Investigaciones Agrobiolo´gicas de Galicia (CSIC), Campus Universitario Sur, Apartado 122, E-15780 Santiago de Compostela, Spain
Keywords: Prescribed fires; Fire fighting agents; Soil properties; Plant growth
Nowadays fire fighting chemicals are being used as water additives to combat wildfires and control prescribed burns for habitat management of forest ecosystems located in Mediterranean countries. However, information on their environmental impact such as the effects of these compounds on both soil (physical, chemical and biological properties) and vegetation is not available. In the present study, the shortand medium-term influence of three different fire fighting agents on burnt soil properties and vegetation cover restoration was examined under field conditions. The study was performed in a heathland on a Humic Cambisol, located in the temperate humid region (Galicia, NW Spain), and subjected to a prescribed burnt. The recovery of the burnt area was studied following the growing of pine trees planted in the plots. The following situations were considered: (i) unburnt soil (US); (ii) burnt soil added with water (BS); (iii) burnt soil added with a foaming agent (BS + Fo); (iv) burnt soil with the fire retardant Firesorb (BS + Fi); and (v) burnt soil added with ammonium polyphosphate (BS + Ap). Soil samples were collected at different times during 1 year (0, 1, 30, 90 and 365 days) and chemical and biochemical properties (pH, total C, total N, inorganic N, available P, d 15N, soluble carbohydrates,
DOI: 10.1016/j.foreco.2006.08.294 E-mail address: [email protected] (T. Carballas).
microbial biomass C and urease and (-glucosidase activities) as well as the growth of the pines planted were measured. The results showed that initially the soil was affected by the prescribed fire and that it tended to recover with time; however, 1 year after the prescribed fire a significant fire effect on most analyzed properties (total C, total N, d 15N, soluble carbohydrates, microbial biomass C and enzyme activities) was observed. The data also indicated that, compared to the burnt treatment, the ammonium polyphosphate was the fire fighting agent most affecting soil properties and pine growth. Initially, ammonium polyphosphate increased notably inorganic N, mainly NH4+-N, available P and soil pH but, except for available P, this effect disappeared at the end of the experiment. A negative effect of ammonium polyphosphate on soil enzyme activities was still observed 1 year after the prescribed fire. The pine growth in plots with ammonium polyphosphate also showed a different trend than that in the other plots. Initially the growth was lower than that presented by the unburnt soil and similar to that observed in the other burned soils; but, after 3 months the growth increased notably reaching after 1 year values even higher than those observed in the unburnt soil.