Biomass and Nutrient Dynamics Associated with Slash Fires in Neotropical Dry Forests

• Published in: Ecology (Durham) Vol. 74; no. 1; pp. 140 - 151
• Main Authors: Kauffman, J. Boone, Sanford, Robert L., Cummings, Dian L., Salcedo, I. H., E. V. S. B. Sampaio
• Format: Journal Article
• Language: English
• Published: Washington, DC The Ecological Society of America 01.01.1993; Ecological Society of America; Brooklyn Botanic Garden, etc
• Subjects: 09 BIOMASS FUELS; 095000 - Biomass Fuels- Environmental Aspects- (1990-); 540210 - Environment, Terrestrial- Basic Studies- (1990-); 553000 - Agriculture & Food Technology; 60 APPLIED LIFE SCIENCES; Aboveground biomass; Agricultural soils; Agronomy. Soil science and plant productions; AIR POLLUTION; Animal, plant and microbial ecology; Applied ecology; ARID LANDS; Ashes; Biological and medical sciences; BIOMASS; BRAZIL; CARBON CYCLE; Combustion; CULTIVATION; DEFORESTATION; DEVELOPING COUNTRIES; Dry forests; Ecotoxicology, biological effects of pollution; ELEMENTS; ENERGY SOURCES; ENVIRONMENTAL EFFECTS; ENVIRONMENTAL SCIENCES; EROSION; Fire ecology; FIRES; Forest fires; Forest soils; Fundamental and applied biological sciences. Psychology; LATIN AMERICA; LOSSES; MINERAL CYCLING; NITROGEN CYCLE; NONMETALS; NUTRIENTS; PHOSPHORUS; POLLUTION; RENEWABLE ENERGY SOURCES; RESOURCE DEPLETION; Soil ecology; Soil nutrients; SOILS; SOUTH AMERICA; Terrestrial environment, soil, air; TROPICAL REGIONS; South America; Brazil; America; Deforestation; Climate; Statistical analysis; Thermal factor; Litter; Tropical zone; Rain forest; Phosphorus; Biomass; Biogeochemical cycle; Nitrogen; Canopy fire; Depth; Carbon cycle; Species diversity; Edaphic factor; Pollution; Humidity; Nutrient; Air pollution
• ISSN: 0012-9658; 1939-9170
• DOI: 10.2307/1939509

Unprecedenteded rates of deforestation and biomass burning in tropical dry forests are dramatically influencing biogeochemical cycles, resulting in resource depletion, declines in biodiversity, and atmospheric pollution. We quantified the effects of deforestation and varying levels of slash-fire severity on nutrient losses and redistribution in a second-growth tropical dry forest (@'Caatinga@') near Serra Talhada, Pernambuco, Brazil. Total aboveground biomass prior to burning was @?74 Mg/ha. Nitrogen and phosphorous concentrations were highest in litter, leaves attached to slash, and fine wood debris (<0.64 cm diameter). While these components comprised only 30% of the prefire aboveground biomass, they accounted for @?60% of the aboveground pools of N and P. Three experimental fires were conducted during the 1989 burning season. In these treatments consumption was 78, 88, and 95% of the total aboveground biomass. As much as 96% of the prefire aboveground N and C pools and 56% of the prefire aboveground P pool was lost during combustion processes. Nitrogen losses exceeded 500 kg/ha and P losses exceeded 20 kg/ha in the fires of the greatest severity. With increasing fire severity, the concentrations of N and P in ash decreased while the concentration of Ca increased. This indicates greater amounts of these nutrients were volatilized (i.e., greater ecosystem losses occurred) with increasing fire severity. Following fire, up to 47% of the residual aboveground N and 84% of the residual aboveground P were in the form of ash, which was quickly lost from the site via wind erosion. Fires appeared to have a minor immediate effect on total N, C, or P in the soils. However, soils in forests with no history of cultivation had significantly higher concentrations of C and P than second-growth forests. Based upon the measured losses of nutrients from these single slash-burning events, it would likely require a century or more of fallow for reaccumulation to occur. However, current fallow periods in this region are 15 yr or less.