PS 3-40 - Survival and growth of the ancient conifer Araucaria araucana after forest fires: Insights for forest restoration in the southern Andes of Chile.

Abstract: The China Muerta National Reserve, in the southern Andes of Chile, is a protected area that was affected by a severe wildfire in 2015. Fire burned ca. 3,765 ha of forest dominated by the ancient conifer Araucaria araucana (araucaria, monkey puzzle tree). Araucaria is quite relevant both ecologically and culturally for indigenous Pehuenche people. Three years after the fire, restoration initiatives were established in sites affected with high and moderate fire severity by planting seedlings of A. araucana in burned areas, considering the presence and absence of biological legacies (BL) as a predictive variable. These BL are remnant or partial canopy cover of vegetation that survived fire, tree logs or similar structures that provide protection for seedlings. lWe also considered areas subjected cattle browsing and totally excluded from livestock, which also served as predictive variable. A total of 180 individuals were established, distributed in areas of high and moderate fire severity. Seedling monitoring was carried out every six months (from 2018 to 2022), and included counting the number of shoots and measuring the height of each seedling as response variables. Our results show that both seedlings height and number of shoots were greater in areas more severely affected by fire, and within this condition, the presence of BL was only significant for height of seedlings, especially 18 months after planting. Overall survival was >80% across the burn gradient. In areas of moderate severity, A. araucana presented a slower growth in height and without a significant effect of BL, nor in seedling height nor in shoot number. There is a significant effect of cattle on both seedling height and shoots number. These two variables (that are good proxies of plant growth) are greater in conditions excluded from livestock, and are more important within areas of high fire severity. These results are encouraging and indicate the good post-fire response of ecologically-valued Araucaria araucana when planted, being an effective strategy for improving and accelerate the recovery and restoration of burned forests.