D. C. Drake and Robert J. Naiman.
2007 Reconstruction of Pacific Salmon Abundance from
Riparian Tree-Ring Growth. Ecological
Applications 17 (5): 1523-1542.
Salmon
were an integral part of society in the past.
Not only were they a good source of calories, but they were also
abundant at certain times in the year.
However, they have not always been a dominant food source. At certain times throughout the history of
the Northwest Coast, other marine foods have been eaten more than salmon. Drake and Naiman have an explanation for
this. Using historical data on salmon
abundance, the authors have shown that the tree rings of Northwest Coast sites
and the salmon population are strongly correlated. The obvious reason for this is that changes
in the environment affect both trees and salmon. This is to be expected. However, the interesting thing about this
article is that the two have shown this happens in cycles. Therefore, it is reasonable to suggest that
since the two are strongly correlated in modern periods, they will also be
correlated in pre-historical periods.
They suggest that it is possible to estimate the abundance of the salmon
population based on the tree rings also used for dendrochronology. Using this method, the authors showed that it
was because of a lack or abundance of salmon that transitions between salmon
dependence and independence occurred.
D. W. Clark.
1984 Some Practical Applications of Obsidian Hydration Dating
in the Subarctic. Arctic 37, (2): 91-109.
Obsidian
hydration dating uses the relatively consistent intake of water of obsidian
flakes to give an absolute date to a piece of obsidian. Obsidian hydration dating has been used for
several decades in all climates, but is more frequently used in cold climates,
especially the Upper Northwest Coast.
The reason it is more useful in cold climates is because temperature has
been known to speed up the hydration process by variable amounts. Still, even the results from cold climates
have not been particularly useful.
Because of these failures, many have abandoned the method altogether as
useless. However, in this article, Clark
attempts to show that in certain cases obsidian hydration dating is
useful. He gives some suggestions that were
not necessarily widely implemented, but were often utilized by the methods
where some dates were corroborated by radiocarbon analyses. Some of these include using a more powerful
microscope to examine the water content, keep the flakes in containers with a
humidity and temperature consistent with their original location, and taking
the average of several pieces sourced to be from the same rock. Since this article was written, even more
powerful methods including new microscopes have been brought in to improve
obsidian hydration dating. I do not know
how popular this method is in modern times.
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