9:00 am - 10:00 am
Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES PhD Final Exam Seminar by Killian Fleurial. This seminar is open to the general public to attend.
PhD with Dr. Janusz Zwiazek
Thesis Topic: Physiological Tolerance Mechanisms of Boreal Forest Tree Species to Climatic and Anthropogenic Stress Factors
Through ex-situ and in-situ experiments, literature analysis, and historical climate data, my thesis investigates tree responses to stressors relevant to post-disturbance boreal forest reforestation and oil sands reclamation. I found that, when growing in phytotoxic media, salt-tolerant tree species were disproportionately affected by root hypoxic conditions. A pH-dependent effect of naphthenic acids on plant roots was revealed, suggesting that a lower pH may not favor plant growth when naphthenic acids are present. Furthermore, as low non-negative root temperatures elicit effects similar to salinity or drought on trees, maintaining stomata open and allowing lower xylem water potentials may be a strategy to maintain growth. In this context, I found that white spruce populations from the climatically dry north and west areas of its species range were anatomically maladapted to drought. However, this likely enables these trees to take advantage of foliar wetting even when precipitation does not meaningfully increase soil moisture.