bald cypress? or were you looking for something evergreen?

otherwise you are looking at a drought tolerant (once established) tree that can take standing water. pretty perfect!

Sitka spruce?

I've seen it growing near a lakeshore in fairly boggy / peaty conditions.

Atlas cedars do NOT like too much water!

Western red cedar, dawn redwood or bald cypress.

Most of the other plants listed as growing well in the spot would rot off in a damp place also. So, it probably isn't, in fact a mire. The cypress is a dryland species, so it might have gotten too damp for it but would seem to be suitable for most other types - if dampness was, in fact the problem for the one tree.

Although blue Atlas cedar grows natively in the Atlas Mountains of Morocco it apparently can do well in rather damp places here - one of the finest I have encountered was on a site so moist in winter I could hardly get to it. It is listed on page 34 of Champion Trees of Washington State by Robert Van Pelt:

Circumference: 16'4"
Height: 88'
Crown Spread: 99'
Date Last Measured: 1995
Location: Redmond, Idylwood Park

Do you have room for a tree like this?

It's not just because I've been hiking in the redwoods almost every 6 weeks on average - but - got room for a coast redwood?

I just located one in Prairie Creek redwoods, called Artemis, that's been written about in a book. It has a brook flowing directly under it, and the tree is likely 1500 years old.

bboy ...

You may be right on that blue atlas cedar as long as it's not a bog. I recall the Cedrus genus as being somewhat tolerant of moisture.

M. D. Vaden of Oregon