Document Type

Thesis

Degree Name

Master of Science (MSc)

Department

Biology

Program Name/Specialization

Integrative Biology

Faculty/School

Faculty of Science

First Advisor

Dr. Jennifer Baltzer

Advisor Role

Supervisor

Abstract

Regular stand-replacing wildfire as a disturbance agent has been shaping the boreal forest for millennia. Historically, forests are well-adapted to wildfire and can recover their fundamental structure and function. However, throughout the circumpolar boreal forest, climate change has been driving increasingly extreme wildfire activity. As a result, the recovery capacity of boreal forests could be overwhelmed, triggering post-fire transitions to alternate states. In conifer forests, transitions to broadleaf dominance, mixed-woods, or a failure to regenerate as forests altogether have been observed following recent fires. However, there is little understanding on whether these alternate outcomes are a new phenomenon. My thesis aims to answer the following questions: 1) Are alternate post-fire recovery trajectories becoming more frequent with time?; and 2) Are there any consistent contexts and drivers that can predict alternate outcomes on a landscape scale? We use a combination of aerial flyover photographs and satellite imagery to identify pre- and post-fire forest composition at sites throughout central Yukon that burned between 1960 and 2010. We then determine post-fire recovery trajectory and whether forest compositional change has occurred. Our results indicate that in conifer forests, post-fire compositional changes have become significantly more common in recent decades. Post-fire trajectories were compared against remotely sensed climate and landscape attributes with a random forest analysis which found that aside from decade, slope and elevation influence post-fire recovery. Specifically, steeper slopes and higher elevations are linked with forest compositional change. Our results indicate that recent observations of post-fire changes in forest composition represent a changing response of boreal forests to increasingly extreme wildfire activity, and that some parts of the landscape, such as higher elevations and steeper slopes, are more vulnerable.

Convocation Year

2026

Convocation Season

Spring

Download

Available for download on Thursday, April 29, 2027

Share

COinS