Where’s the Oldest Tree in Washington State?

I seen to be going over the Blewett Pass often over this past year. And one question keeps popping into my head, "Where's the oldest tree in Washington State? Is it on Blewett Pass? Is it in Eastern WA, or on the coastline? I found answers!

The Oldest Tree in Washington State is...

The Thuja Plicata measuring at 18.80 m

Located in the Olympic National Park in Kalaloch (Jefferson County) Washington

"This tree is called "Kalaloch Redcedar". This tree was for a large part destroyed by a coastal storm on March 8th 2014. Half of the tree fall down, the other half is still standing." - Western Redcedar 'Kalaloch Redcedar' in Olympic National Park in Kalaloch, Washington, United States (monumentaltrees.com)

Yes, that is a picture of the fallen largest tree in Washington State.

The second largest/oldest tree in Washington State is called the "Sitka Spruce."

"This tree is called "Quinault Lake Spruce". It is the third largest Sitka spruce by volume (298 cubic metres or 10,540 ft3). The measurements are from Van Pelt, R. (2001): Forest Giants of the Pacific Coast. Sitka spruces often start life in the wild on nurse logs, like this one, which results in very large bases. This tree has the largest base of any of the species.

The girth of the tree, measured at a height of 1.37 m, is 16.90 m (2001, "Forest Giants of the Pacific Coast"). Its height is exactly 58.20 m (2001, Laser with Two-point measurement (e.g. Nikon Forestry 550/Pro) - sine method, "Forest Giants of the Pacific Coast")." -Sitka Spruce 'Quinault Lake Spruce'(monumentaltrees.com)

How do we know though?! There are so many trees, how does one know when they have found the "oldest/largest?" Just food for thought.