Imagine a world with larch trees in the uplands and dawn redwoods in the flats, and bald cypress trees in the wetlands. This existed in the Eocene (~40 million years ago) when the world was warmer, the treeline was at higher latitudes and altitudes, and carbon dioxide in the atmosphere was more than two times Earth’s preindustrial levels. In fact, in the high Arctic where no trees can survive today, deciduous conifers were as lush in terms of carbon sequestration and bioproductivity as today’s rain forests. Now, imagine a world that is sliding back into the greenhouse after millions of years of relative icehouse conditions.
How can we better understand the role of deciduous conifers in the biosphere and their utility in a warmer world. One “natural” experiment is to use dendroclimatology to infer the response of deciduous conifers to a warmer and wetter world. Secrest Arboretum in Wooster, Ohio has two species of larch trees (Siberian and European) as well as bald cypress and dawn redwood trees. These species are all exotic to Ohio and have been growing in the arboretum in some cases for over 100 years. How do they grow in their new homes? This is the subject
A New Tree Ring Study from the Kashmir Valley, western Himalaya
The global tree-ring community is racking up the papers investigating the utility of the relatively new proxy using blue intensity of annually-dated tree rings. This latest effort is a blue intensity investigation followup of a recent study on ring widths also led by Dr. Santosh Shah of Birbal Sahni Institute of Palaeosciences in Locknow, India. Blue intensity is a proxy that has added a new dimension to thermal histories across the globe including efforts at the The College of Wooster Tree Ring Lab. Shah et al. (2025) used cores extracted from three sites of the Western Himalayan Fir (Abies pindrow) from the Kashmir Valley.
Map from the study showing the location of the three tree-ring sites and the meteorological station (Srinager). The centrally-located Srinager climate station has records of precipitation and temperature spanning 1901-2024, one of the longest in the region.
A figure from the paper showing the beautiful images of earlywood (above) and latewood (below) blue light reflectance for individual rings from the Western Himalayan Fir (Abies pindrow).
The upshot of the work is that time series of blue intensity values from the latewood of A.Pindrow are strongly correlated with monthly average and maximum temperature series from nearby climate station (Srinager). Ring-width are
Juneau Recap (SEAK 25)
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
Angoon Day 3 – Pt. 1: Turn Point (SEAK 25)
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
Keck (SEAK25) Week 2: Dendrochronological Methods
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