Author: Daniel Heltberg, BSc Environmental Science, University of Aberdeen

Project Title: Is this boreal life? Reconstructing the intensity of boreal wildfires over centennial and millennial timescales

Supervisors: Dmitri Mauquoy, Daniel Coathup, & Thomas Theurer

My name is Daniel. I am a 3rd year environmental science student. This past summer, I worked with Dmitri Mauquoy, Daniel Coathup, and Thomas Theurer. Our investigation required us to develop novel techniques to image and quantify locally combusted boreal forest charcoal found in peat.

Dmitri Mauquoy and Dan Coathup are researchers interested in uncovering how climate differed thousands of years ago compared to today. The amount of rainfall, the average temperature, and the topography of the landscape have changed dramatically over the course of time. Previous ecosystems and these changes are preserved in the natural environment. It only takes a keen scientist to unveil them.

Peat environments record the biota that grew in them due to their cold, acidic, and anaerobic conditions. For our project, we analysed 2 adjacent peat profiles from a forest hollow in Finland. Because the profiles overlapped slightly, and because neither extended over a meter, we matched them to represent a larger period of time in this environment. The age of a peat can be estimated in various ways. Carbon-dating approximates the bottom of our profile to 10,000 years old.

Figure 1: Carbon dating chronology of the Korte Hollow peat profiles.

Besides the age of our profile, there are 3 main surveys of the paleoclimate that we performed.

  1. Accumulation rate of organic matter. Loss-on-ignition (LOI) is a method for calculating organic matter in a substance that bakes the carbon out, leaving only the inorganic mineral material behind. By comparing the weight of the material before and after baking, we can determine what % of it is organic. With this measurement at every segment of our profile, we can determine how organic matter accumulation concentration varies. Corresponding this with our C-dating measurements, we can quantify organic matter accumulation in this locality over 10,000 years.
  2. Burning intensity. By studying how much charcoal is in each segment of our peat profile, and measuring the individual responses to bombardment by a laser, we can estimate the heat (intensity) of the fire that produced the charcoal. To easily identify and count the charcoal, we bleached every segment of peat with hydrogen peroxide. Afterwards, we photographed the segments and ran them through an imaging software known as FIJI.
  3. Floral composition and burning input. Another way we analysed the data from FIJI was in the shape of the burned particles. Aspect ratio (AR) compares a shape’s height and width. By knowing the approximate AR of the floral species found in forest peat hollows, we can roughly estimate what was burned at a certain period in time.
Figure 2: 1 cm3 of bleached peat at segment 61 on KH22B.

The science aside, I gained an appreciation for the interdisciplinary skills required to study our natural environment. The challenges I faced in collecting and processing the data required me to ask for help and learn from others. I thank Dmitri, Daniel, and Thomas for their kind words and encouragement throughout (plus the wee bit of banter here and there). I am also grateful to the University of Aberdeen, the UoA School of Biological Sciences, and NERC for enabling this research placement. This experience has strengthened my resolve to pursue a career in environmental science.