Wildfires negatively impact conifer regeneration and growth

Ectomycorrhizal fungi (ECM) and soil nutrients are important for conifer growth and regeneration. ECM engage in a symbiotic relationship with conifers, with the fungus conferring nutrients such as nitrogen and phosphorous to their host tree in exchange for carbohydrates they receive from the tree. This project examined the effects of wildfires on ECM and soil nutrient content and observed how these changes may affect conifer regeneration post-fire. In 2012, the Arapaho fire spread through the Rogers Research Site located in the Northern Laramie Mountains of Wyoming. The fire altered ECM and soil nutrient levels and killed a large number of conifers. In order to examine the fire's effects and different restoration techniques, a block design was implemented at the field site, and soil was collected from both high-severity (burned) and low-severity burned (control) plots five years post wildfire. Pine seeds were planted in both types of soil in microcosms and were incubated for a period of fourteen months in growth chambers. In February, the seedlings were harvested and analyzed based on their length and biomass. It was observed that trees grown in soil from the control sites grew more on average and exhibited a higher seedling biomass than trees grown in soil from the burned sites, indicating that changes implemented by wildfires do negatively impact conifer regeneration. In order to combat the negative effects of wildfires, both ECM and nutrients may need to be introduced to these areas post-fire. This can be accomplished either by inoculating burned areas with soil from non-burned sites, or by transplanting seedlings grown in the lab in non-burned soil to burned areas.