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Controlled burning is commonly used by farmers on forestry lands to clear the land prior to establishing agricultural crops. The objective of this experimental work was to evaluate the behavior of fire in controlled burning on forestry lands in the Sancán commune, province of Manabí, Ecuador. 10 plots of 1.18 x 5 m were delimited in fuel rows and three plots of 20 x 50 m in dispersed fuels. During the burning, the variables air temperature, relative humidity and wind speed were measured at 0.50 meters above the ground and more than 3.00 m away from the end of the plot where the fire started. The fuel material was characterized considering weight, thickness and moisture content before burning. The fire behavior parameters evaluated were propagation speed, linear fire intensity, flame heights, lethal drying height and heat released per unit area. Fire behavior showed higher mean values for all parameters in the plots located in the fuel rows, except for the case of propagation speed. Besides, in these plots, the standard deviation values obtained for each variable indicate greater dispersion of the data with respect to the mean, which implies less homogeneous fire behavior in a general sense. The results obtained can be used to support the responsible use of fire in forestry lands. [ABSTRACT FROM AUTHOR]

Controlled burns have been used to manage pastures, forests and agricultural fields for centuries. Defended by some and criticized by others, until today, there is still no consensus in the scientific community about the effects caused by fire on soil. This study had the objective to analyze the effect of controlled burns on soil pH, H+Al, Al3+, Na+, K+, P, O.M., Ca2+, Mg2+, and N. For this propose, two different pasture plots were burned and had the fire intensity quantified. The burned soil, and from an adjacent control plot, were collected at three different moments: immediately, one and six months after the burns. The burns presented low intensity ranging from 23,7 to 30,91 kJ m-1 s-1. Immediately after the burns the values of pH, Na+, Ca2+, K+ and P increased in the burned plots and were significantly different from the control plot. However, six months after the burns, only the amounts of K+, P and Ca2+ remained significantly larger than the controlled. Despite the values of the N and H+Al in burned and control areas were similar immediately and one month after the burns, after six months the amount of N was significantly larger in one of the burned plot, while the H+Al was significantly bigger in the control plot. The amounts of Mg2+, O.M. and Al3+did not change during the study period. The found results suggest that low-intensity controlled burns can reduce soil acidity and be effective in increasing some essential nutrients for plant development in short term. [ABSTRACT FROM AUTHOR]

Scientific research that purports to evaluate Indigenous fire regimes in the absence of ethnographically contextualized ecological data runs the risk of exacerbating the fire blame game and providing evidence to support distorted narratives advanced by anti-Indigenous advocates. Spatial analysis of fire scars in Indigenous territories can be an effective tool for characterizing cultural fire regimes in terms of distribution and frequency, especially when qualified by linkages to different local ecosystems. A recently published article drew on fire scar mapping from satellite imagery to assess anthropogenic fire distribution and frequency in the Pimentel Barbosa Indigenous Land, Central Brazil. The authors use their findings to characterize A'uwē (Xavante) use of fire as unmanaged and a model of unsustainable use of cerrado resources. In this article, we discuss Aguiar & Martins's recent paper in light of our long-term research on A'uwē hunting with fire in the Pimentel Barbosa Indigenous Land, arguing that A'uwē hunters do burn according to established cultural protocols, manage their use of fire for conservationist purposes, and do not cause environmental degradation by burning. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the characteristics of surface fuel during the dry season in areas with different periods without occurrence of burn, in the grasslands phytophysiognomy of the Cerrado in the Jalapão region of Brazil. Fuel sampling was conducted in areas with different periods without burning over four months during the dry season (May, June, August, and September). A total of 128 samples, named as data samples, were established, from which eight subsamples designated as parcels of fuel sampling were collected. In each parcel of fuel sample, we evaluated variables related to non-destructive methods such as the height of grass vegetation (Htg), litter height (Htl), number of species (Nsp), and number of individuals (Nin), as well as variables related to the destructive method for obtaining the fuel load. The fuel was separated according to its physiological state and diameter (time-lag). The Htg variable was highest and was stabilized by the second year post-burning. Nsp showed a reduced number of areas after four years without burning and in the last month of the dry season. The behavior of the dead grass fuel (Dg) load in the samplings collected in the first two months of the dry season was the only variable that increased in the different years without burning. These results are important for management initiatives of Cerrado grassland fuels in the Jalapão region. [ABSTRACT FROM AUTHOR]