Resumo

URRETAVIZCAYA, María F et al. Soil and vegetation conditions in three burned Nothofagus pumilio forests in Argentina and experiences for their active restoration. Ecol. austral [online]. 2018, vol.28, n.2, pp.383-399. ISSN 1667-782X.

Fire is an important disturbance affecting Nothofagus pumilio (lenga) forests in Chubut and Santa Cruz provinces of Patagonia, Argentina. Depending on the forest structure and the level of fire severity, the resulting stands could substantially differ from the original. In this study, we evaluated post-fire effects on soil and vegetation conditions that might affect reestablishment of lenga plants in three latitudinal areas of its natural distribution in Patagonia: La Colisión (LC) 42°56' S, Monte Zeballos (MZ) 46°49' S and Río Turbio (RT) 51°29' S. The fire events occurred one (LC), seventy (MZ), and twenty-seven (RT) years before treatments establishment, respectively. In each site, we characterized species richness and cover at burned areas, and analyzed 12 physicochemical properties of the first 10 cm of soil depth at burned and adjacent unburned (control) areas. In burned areas, we performed active restoration experiments by planting lenga seedlings using different protection devices. Soil cover was higher in RT. While plant relative cover according to habit and origin differed between sites, species richness and diversity were similar. Differences in soil physicochemical properties between burned and unburned areas could be associated to the time passed since fire occurrence. At the end of the first growing season, and regardless of the protection device used, survival was high at all sites (>70%). This percentage slightly decreased in the subsequent years. In MZ and RT, European hares browsing limited seedling growth. In burned and grazed lenga forests, herbivores restrict the natural regeneration. Restoration by planting lenga seedlings could be a viable alternative by providing protection to hare browsing.

Palavras-chave : Temperate forests; Patagonia; Lenga; Fire; Richness and diversity; Soil properties; Plantation.

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