PARENT SESSION
Poster Session 37: Forest Ecology.
Thursday, August 5 Presentations from 5:00 PM to 6:30 PM, Exhibit Hall A 1.
Combined effects of competition and burn treatments on Pinus ponderosa germination and survival (Black Hills, South Dakota).
Bonnet, Véronique1, Schoettle, Anna1, Joyce, Linda1, 1 Rocky Mountain Research Station, Fort Collins, CO
ABSTRACT- Regeneration success of trees is dependent on environmental conditions and biotic interactions. After a disturbance, patterns of regeneration success will determine the future tree distribution and forest structure. Ponderosa pine benefits from conditions created by wildfires but can be very sensitive to inter-specific competition pressure. The objective of our study was to determine the effects of burn severity combined with competition pressure in situ after a wildfire. In 2000, the Jasper Fire burned 34,000 ha of ponderosa pine forests in the Black hills of South Dakota. Three years after the fire we tested, in the field, the combined effects of competition and burn treatments on ponderosa pine germination, growth and survival using seeds sown inside protected plots. Three burn severities (unburned, moderate severity burn, high severity burn) were compared, and within each burn severity, three competition treatments were applied: no competition, root-only competition and root plus shoot competition. The results showed that ponderosa pine germination, growth and survival is sensitive to both burn severity and competition treatments. Germinated occurred earlier in high severity burn treatments but growth was slowed compared to the unburned or moderate severity burn treatments. Both root-only competition and root plus shoot competition reduced growth compared to the no competition treatment. The survival was better in moderate burn severity and in the no-competition treatments. There was no interaction between competition and burn severity treatments on ponderosa pine regeneration success.
Key words: Fire ecology, Burn treatment, Pinus ponderosa regeneration , Competition treatment