The flammability of ornamental species with potential for use in highways and wildland urban interface (WUI) in southern Brazil

Abstract

The areas of wildland urban interface (WUI) are sites that have mixed characteristics, from the influence of rural and urban areas. With the increase in urban population in national and global level, the areas are losing this characteristic transition with diversity of functions. One of the most common problems due to this rural/urban proximity are forest fires that cause damage to many homes in urban areas. The highway is a transportation infrastructure located in the area of the wildland urban interface that can serve as a barrier or mitigation of forest fires that threaten urban areas, through its landscaping. For the highway integrate with the local landscape is necessary that this landscaping provide conservation or ecological, cultural and aesthetic function. The objective of this study was to evaluate the flammability of native ornamental species with potential for use in the prevention of forest fires in the vicinity of highways. The selected species are native from southern Brazil due the presence of interesting aesthetic features. They are: Aspilia montevidensis (Spreng.) Kuntze - the family Asteraceae species with ornamental potential both by the beauty of the flowers of bright yellow color, like the long flowering period that occurs almost all year round and can be used in landscaping as ground cover, is indicated for public areas by not requiring maintenance and also for treatment of degraded areas; Peltodon rugosus Tolm. - herbaceous species of the family Lamiaceae, native to southern Brazil, on “Estepe Gramíneo-lenhosa” presents both its ornamental inflorescence globose form and by its leaves with visible vein, can be used in degraded areas due to its hardiness; and Verbena rigida Spreng - the Verbenaceae family, is a little branched herbaceous perennial, rhizomatous, erect, popularly known as “grass-wire”, native of the fields of the plateau in southern Brazil, can reach 20-30 cm in height with decorative flowering, stiff and rough leaves, inflorescences with small flowers blue-purple color formed in spring-summer. For each species were performed 50 burnings in epiradiator of 1 g of material freshly harvested. During the experiments burning in the epiradiator, the following variables were collected: Frequency of ignition (FI), time to ignition (TI), duration of combustion (DC), flame height (AC) and combustion index (IC). Statistical analysis was done by SNK test at 95 % probability. The results of the species flammability show that Aspilia montevidensis and Peltodon rugosus differ statistically of the Verbena rigida for FI and TI, indicating to be less flammable, although all species show low flammability. Given the results, it is concluded that the analyzed species exhibit excellent characteristics for landscape composition on highways both due its aesthetic appearance and functional, and can also serve as a barrier against forest fires in areas of wildland urban interface in southern Brazil.