Experimental post fire restoration of Nothofagus pumilio and N. antarctica forests in Tierra del Fuego, Argentina

MATTHEW JOSEPH RUGGIRELLO; GIMENA NOEMÍ BUSTAMANTE; PETE FULÉ; ROSINA SOLER

Congreso; INTERNATIONAL LIAISON COMMITTEE FOR THE 8th; 2023

AGIF

Wildfires in the native Nothofagus forests of Tierra del Fuego, southern Argentina, impede post-fire regeneration of N. pumilio and N. antarctica. Regeneration densities are lowest in the interior of burned areas where microsites are dominated by grasses and forbs rather than leaflitter. To develop strategies to improve regeneration in the interior of burned areas, we established a restoration experiment in forests that burned at different points in time over the last century. In early-Autumn (April), 2022, we collected approximately 19,000 N. pumilio and 36,000 N. antarctica seeds from different provenance sources. We tested the viability of these seeds via flotation tests and selected full individuals that sank for sowing. In late-Autunm (May), 2022, at burned plots located 30m and 270m from the unburned forest edge, and in unburned controls (n=96), we selected 5 microsites per plot (grass/forb, leaflitter, bare-soil, bush, and woody-debris-dominated). Within a 20cm2 subplot at each microsite we removed naturally deposited seeds and sowed 30 previously selected seeds. Leaflitter from unburned forests was used to create leaflitter-dominated microsites when they were not naturally present. Seed germination and average seedling height will be recorded in December, 2022, and survival and height growth will be measured in March, 2023. We expect that seeds sown in leaflitter will have higher germination rates, and improved survival and height growth compared to those sown in other microsites. This outcome would give local land managers an additional resource through which to improve post-fire restoration efforts and mitigate the negative impacts of wildfire on N. pumilio and N. antarctica.