Flammability of native species of two Brazilian ecosystems

Abstract

A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitalis, UC Pombalina e UC Impactum, pressupõem a aceitação plena e sem reservas dos Termos e Condições de Uso destas Bibliotecas Digitais, disponíveis em https://digitalis.uc.pt/pt-pt/termos. Conforme exposto nos referidos Termos e Condições de Uso, o descarregamento de títulos de acesso restrito requer uma licença válida de autorização devendo o utilizador aceder ao(s) documento(s) a partir de um endereço de IP da instituição detentora da supramencionada licença.Ao utilizador é apenas permitido o descarregamento para uso pessoal, pelo que o emprego do(s) título(s) descarregado(s) para outro fim, designadamente comercial, carece de autorização do respetivo autor ou editor da obra.Na medida em que todas as obras da UC Digitalis se encontram protegidas pelo Código do Direito de Autor e Direitos Conexos e demais legislação aplicável, toda a cópia, parcial ou total, deste documento, nos casos em que é legalmente admitida, deverá conter ou fazer-se acompanhar por este aviso. AbstractThe Cerrado (Brazilian savanna) presents species with adaptations to fire and, therefore, is considered a fire dependent ecosystem. On the other hand, the Mixed Ombrophilous Forest (FOM), characterized by the presence of higher levels of moisture, is considered a fire sensitive ecosystem. Flammability is defined as the ability of the fuel to ignite after being subjected to an increase of caloric energy, until the material reaches the ignition stage, after the reduction in the moisture content. The objective of this research was to test and classify species from the Cerrado and the Araucaria Forest (FOM) according to their flammability. The following species from the Cerrado were tested: Vatairea macrocarpa, Myrcia splendens, Davilla elliptica, Ouratea hexasperma, Copaifera langsdorffi, Diospyros hispida. The tested species from the FOM were: Ocotea puberula, Araucaria angustifolia, Allophylus edulis, Cupania vernalis and Luehea divaricata. Using an epirradiator, 50 replications of burning for each species were carried out. Each tested sample consisted of 1.0 ± 0.1 g of green fuel material less than 0.7 cm of diameter, containing leaves and branches. The measures parameters were: Time of ignition (Ti), combustion duration (Dc), ignition frequency (Fi) and flame height (Hc). The species were classified according to their flammability rating value (Vi). To validate the classification and determine which parameters were the main flammability inductors, a Principal Component Analysis (PCA) was carried out. Araucaria angustifolia presented poor flammability, due to the higher ignition time. Allophylus edulis presented the higher flammability among the FOM species, and the ignition frequency was the decisive parameter to this classification. The species from the Cerrado showed similar values of combustion duration, except Davilla elliptica and Myrcia splendens, which presented intermediate values of ignition time. Vatairea macrocarpa and Copaifera langsdor...

Fire severity in slash-and-burn agriculture in southern Brazil: an overview

“…Several studies of fire dynamics at the ground surface found no correlation between surface temperatures and litter load in dry eucalyptus forests (Eucalyptus marginata) in Australia (Wotton et al, 2012). In the present study, Mixed Ombrophilous Atlantic Forests produce a high amount of litter, with an average of 6.097 t ha -1 yr -1 (Antoneli and Thomaz, 2012), with a lower number of species that produce resins and other fuel elements, conferring a low level of flammability and combustion (Santos et al, 2018). This indicates that larger litter layers in this system can be used as fire protection elements from the top of the soil.…”