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Russian Birch Climate Reconstruction- Part 2
Guest blogger- Clara Deck
This summer, I am working with Dan Misinay to continue a dendrochronology project focused on Kamchatka, Russia. We have been working with birch tree cores (Bertula ermanii) collected from the region by Dr. Wiles and I.S. student Sarah Frederick in the summer of 2014.
Our goal is to use the cores to gather information about the climate. By counting, measuring and comparing different cores, Dan and I developed separate tree ring width chronologies from different areas in Kamchatka.
My samples are labeled NR in the northern part of the Kamchatka peninsula, while Dan’s are labeled UG. SANO represents birch cores in a study by Sano et al, 2009. The UG and SANO data correlates very well together, but the NR data is in a much different latitudinal location, and does not correlate. With the Sea of Okhotsk to the east, the Pacific Ocean to the West, and numerous mountain ranges and volcanoes, there are many climate factors that may influence the growth of these trees along the peninsula. The following work deals solely with my samples (NR).
Shown here in green is the standardized data for the entire chronology (1823-2014). Trends in this graph may indicate climate signal and will be further analyzed this summer. The blue line represents the number of samples for each given year.
I compared my tree ring data with meteorological data from a nearby weather station in Kljuci, Russia (also spelled Klyuchi). This graph shows the correlation of the tree rings with the minimum temperatures for each month. Months from the previous year are labeled t-1, while the present is year t. High positive correlations are shown during March through August of the present year, indicating that minimum temperatures in these months primarily influence the tree ring widths. Though this graph only shows correlations with minimum temperatures, I found the same trend with maximum and mean temperatures.
The map above shows a zoomed in region of northeast Kamchatka with spruce (Picea) and larch (Larix gmelinii) samples from a study called Constraining recent Shiveluch volcano eruptions (Kamchatka, Russia) by means of dendrochronology (Solomina, et al 2008). Shiveluch volcano is adjacent to the site where the birch tree samples were collected, and all of the samples shown could be affected by its volcanic activity. It is one of the most active volcanoes in Kamchatka, and a significant eruption was recorded in 1964 (Solomina, et al 2008). The tree ring record should show evidence of this eruption in the year 1965. The study indicated that although a slight decrease was shown in their cores, it was of negligible scale and does not provide clear evidence of the eruption. I am interested to see if my samples show evidence of the eruption, because of its different position relative to the volcano.
Shown here is isolated data from 1950-1980 from the above shown chronology, and shows a drop off in ring width growth in 1965. This could be evidence of a volcanic eruption, but as you can see even in this small data set, variability like this is not uncommon. More work needs to be done to determine the significance of this decrease.
References:
Sano, M., Furuta, F., and Sweda, T., 2010, Summer temperature variations in southern Kamchatka as reconstructed from a 247-year tree-ring chronology of Betula ermanii: Journal of Forest Research, v. 15, p. 234–240, doi: 10.1007/s10310-010-0183-z.
Solomina, O., Pavlova, I., Curtis, A., Jacoby, G., Ponomareva, V., and Pevzner, M., 2008, Constraining recent Shiveluch volcano eruptions (Kamchatka, Russia) by means of dendrochronology: Natural Hazards Earth Systems Sciences, doi: 10.5194/nhess-8-1083-2008
Source: http://woostergeologists.scotblogs.wooster.edu/2015/06/12/russian-birch-climate-reconstruction-part-2/
