Guest Blogger Keck SEAK25: We bookended our time in Alaska with hiking, tree coring, and fish consumption in Juneau.

Starting off strong with a hike to see Herbert Glacier.

We were lucky enough to stay at the University of Alaska Southeast’s housing right on Auke Lake. The daily dips and wades that happened here will be dearly missed!

To cap off the first portion of our time in Alaska before heading to Angoon, the group hiked up Mt. Roberts.

Once we returned from Angoon the group split up to enjoy a day off. Lynnsey, Lev, Landon and Izzy enjoyed 360 views at the top of Mt. Juneau. Dexter and Nick caught rockfish and halibut (not pictured, but thoroughly enjoyed) at Tee Harbor.

The team then got creative on a hike up to Salmon Creek Reservoir.

Finally, we spent a beautiful last day in Alaska taking Mountain Hemlock cores at Mt. McGinnis (the MT site) overlooking the Mendenhall glacier. The MT tree ring site is a classic published by the Wooster Tree Ring Lab and many others – the group will update the efforts of Gordon Jacoby, Nicole Davi and Greg Wiles who originally sampled the site in 1997. 
The work of Keck SEAK25 is funded

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Guest Bloggers – SEAK25: On the third and final day in Angoon, we split into two groups. One climbed Hood Bay Mountain to extract high-elevation mountain hemlock cores, the other kayaked to Turn Point, searching for and coring culturally modified trees (CMTs). 
The CMTs at Turn Point are Sitka Spruce that have distinct scars with hack marks, evidence of previous Tlingit generations harvesting sap and fire starter. These CMTs are of heightened interest because a new hydroelectric power plant is soon to be built, and its road will require the removal of many trees in Turn Point. High school students in Angoon have already worked to preserve the CMTs by creating photogrammetric renderings. This work will prevent the information from there valuable trees, which connect locals to their lineage, from being lost altogether. We hoped to contribute to the effort by extracting cores to investigate their growth and date the scars using tree rings.

A map showing Turn Point in relation to Angoon. Turn Point will be the site of a hydroelectric plant for power generation for Angoon, which is now powered by a diesel generator. 
We embarked on this mission in the morning, leaving from the seaplane dock on kayaks. We had

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Dendrochronological methods are a key part to our research team’s success. While analyzing and drawing conclusions from data is essential, it is equally as important to ensure the proper collection, preparation, and handling of samples and extraction of ring measurements. There are many key steps to this process in dendrochronology, that when done correctly, ensures the success of a research team.
Taking samples
Tree cores are extracted using an increment borer. By manually drilling the auger into a tree, the core is preserved inside the increment borer with minor injury to the tree. The core extractor, a half circular metal tray, then fits into the auger bit. After cranking the handle counter clockwise, the core then fully separates from the body of the tree. Pulling the core extractor out of the auger allows the extraction of a tree core.

Increment borer.
Selecting the right tree within a stand is crucial to obtaining a good sample. It is important to consider factors such as tree health and direction of lean before coring. Trees that lean excessively can be more difficult to core, as the wood is under more directed pressure. We aimed for trees that stand tall, with little to no lean. If there is

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Figure 1. Title page of Amanda’s thesis including one of the key figures.
Amanda Flory (class of 2025) completed a thesis that investigated the interplay between the pace of the ocean-atmosphere climate in the Northeast Pacific that is dominated by Pacific Decadal Variability along with the volcanically-forced coolings inferred from tree-ring records. Her title page (above) summarizes the results with several known volcanic intervals linked with decade-long coolings. These coolings are inferred from a tree ring-width series located in coastal Southeast Alaska (Dude Mountain, Ketchikan, Alaska). In addition to her thesis work Amanda presented her results at the meeting of the Geological Society of America in the Spring of 2025. The take-home here is that the variability as recorded in the tree-ring record appears to be a combination internal variability of the Northeast Pacific [1] and volcanic forcing [2] contributing to the decadal variability in the climate.

Figure 2. The author (left) cores a yellow cedar (Cupressus nootkatensis) – Nick (middle) and Proto provide support.

Figure 3. Comparisons of Sitka, AK temperature records for the months of December through October of the growth year correlated with the Dude Mountain ring-width record.
This climate/tree-ring comparison (Figure 2) examines the moving correlation over time (since

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