The Trees of Mount St. Helens

Katharine Napora with a slice of a Bald Cypress tree.

Katharine Napora has been working at the Center for Applied Isotopes for a little over 1.5 years now. As an Environmental Archeologist, her job is to research the relationships between humans and the environment in the ancient past and find connections to the relationships of today. Specifically, Napora has been doing research regarding the 1980 Mt. Saint Helens eruption.

Napora, along with Drs. Jeff Speakman, Doug Dvoracek and Kathy Loftis are taking a look at tree rings found around the eruption site. They sample the trees by taking a metal instrument, called a increment borer, that twists into the tree horizontally and pulls out a core showing all the rings the tree has made. This prevents the team from having to cut down a tree to retrieve a sample.

The cores from Douglas fir, Spruce and Western Hemlock trees found in the Mount Saint Helen area that Napora looks at.

Napora shows us that each ring within the core symbolizes a year of the tree’s life. The size, color and composition of these rings differ greatly depending on a variety of conditions, such as rainfall, Napora tells us.

The team then takes these cores and looks at the concentrations of different elements.

She tells us that what they are interested in seeing is whether they are able to find any abnormalities in the rings during the time of the eruption.

“For example, we might see a series of very small rings after 1980 that could indicate that the force of the eruption blew all of the needles off of the trees, and it took them several years to recover.”, Napora says.

Bald Cypress tree slice — Napora tells us from one needle to the next, 100 years have gone by.

Napora says that by looking at long series of tree rings, we can determine a baseline of normal conditions in the past. Deviations from these normal conditions, like spikes in certain elements, can indicate unusual environmental conditions.

Napora also told us, “Establishing baseline conditions by looking deep into the past can tell us what is within normative fluctuations of the environment,” says Napora.

section of a Bald Cypress tree

“Archaeology and palaeoecology have a major role to play in informing us about long-term trends in the climate and environment, and understanding these trends is, I think, vital to preparing for the effects of climate change in our own era”, Napora says.

Napora tells us that she, and the rest of the team working on this project, are hoping to be able to identify eruptions in the ancient past with this new information from the Mount St. Helens site.