Pine Plantations and Invasion Alter Fuel Structure and Potential Fire Behavior in a Patagonian Forest-Steppe Ecotone

PARITSIS, JUAN; LANDESMANN, JENNIFER; KITZBERGER, THOMAS; TIRIBELLI, FLORENCIA; SASAL, YAMILA; QUINTERO, CAROLINA; DIMARCO, ROMINA; BARRIOS-GARCÍA, MARÍA; IGLESIAS, AIMÉ; DIEZ, JUAN; SARASOLA, MAURO; NUÑEZ, MARTÍN

Forests

MDPI Open Access Publishing

Año: 2018 vol. 9

Planted and invading non-native plant species can alter fire regimes through changesin fuel loads and in the structure and continuity of fuels, potentially modifying the flammabilityof native plant communities. Such changes are not easily predicted and deserve system-specificstudies. In several regions of the southern hemisphere, exotic pines have been extensively planted innative treeless areas for forestry purposes and have subsequently invaded the native environments.However, studies evaluating alterations in flammability caused by pines in Patagonia are scarce. In theforest-steppe ecotone of northwestern Patagonia, we evaluated fine fuels structure and simulated firebehavior in the native shrubby steppe, pine plantations, pine invasions, and mechanically removedinvasions to establish the relative ecological vulnerability of these forestry and invasion scenarios tofire. We found that pine plantations and their subsequent invasion in the Patagonian shrubby steppeproduced sharp changes in fine fuel amount and its vertical and horizontal continuity. These changesin fuel properties have the potential to affect fire behavior, increasing fire intensity by almost 30 times.Pruning of basal branches in plantations may substantially reduce fire hazard by lowering theprobability of fire crowning, and mechanical removal of invasion seems effective in restoring originalfuel structure in the native community. The current expansion of pine plantations and subsequentinvasions acting synergistically with climate warming and increased human ignitions warrant ahighly vulnerable landscape in the near future for northwestern Patagonia if no management actionsare undertaken.