Giant sequoias: There are less than 80,000 of these redwoods left in California,

[PufPuf23]

5. There is a 3rd redwood species, the living fossil, Dawn Redwood.

First, the tree you saw driving to Portland is a planting outside the natural range.

Not unusual, the redwoods are planted frequently outside their range.

Have personally visited redwood plantings in UK. In 1994 went to UK with then wife and usually when traveled was interested in the forests. One goal was to attend a book fair in Hay-on-Wye (the town of books according to wiki). Bought a used book on The Trees of Wales (1947). The next two nights we had reservations in Welshpool, Wales. The dated book said the tallest and largest trees in UK were near Welshpool just by coincidence. The tallest tree being Abies grandis (coastal white fir) and the largest a Giant Sequoia (this may not be true now or even then). The largest tree was a Giant Sequoia we did not see.

Went driving in general area and saw from distance what looked like grove with tall tree. Went as close as could be road, climbed a rock fence probably trespassing. Soon we were in a grove with the tallest tree mixed in a planting with Douglas-fir and coast redwood and a trail that we followed. The forest grew tamer and then we were in a younger grove of pure coast redwood, looked just like a young growth redwood forest in my home, Humboldt County. Proceeding on the trail, there started to be markers and explanatory info. We were on a formal nature trail and soon were at trailhead in a parking lot with a building the housed the Royal Forestry Society, the improvements developed after the 1947 book.

The next day we had to leave having reservations that night in Bath and the next day in Stratford on Avon. Just outside of Welshpool here was a funky old buy active sawmill and had to stop. We were approached by a fellow that was the forester for Welshpool Castle (that we had not visited). He explained the sawmill was for use for repairs and replacement at the Castle that had acreage and an active commercial timber program and invited us to tour but we had to continue (and never have been back).

Back to Dawn redwood (which is deciduous and beautiful)

Metasequoia (Dawn Redwood)

Metasequoia, or dawn redwood, is a genus of fast-growing coniferous trees, one of three species of conifers known as redwoods. The living species Metasequoia glyptostroboides is native to Lichuan county in Hubei province, China. Although the shortest of the redwoods, it grows to at least 165 feet (50 meters) in height. Local villagers refer to the original tree from which most others derive as Shuǐshān (水杉 , or "water fir", which is part of a local shrine. Since its rediscovery in 1944, the dawn redwood has become a popular ornamental, with examples found in various parks in a variety of countries.

Together with Sequoia sempervirens (coast redwood) and Sequoiadendron giganteum (giant sequoia) of California, Metasequoia is classified in the Cupressaceae subfamily Sequoioideae. M. glyptostroboides is the only living species in its genus, but three fossil species are known. Sequoioideae and several other genera have been transferred from the former family Taxodiaceae to Cupressaceae based on DNA analysis.

https://en.wikipedia.org/wiki/Metasequoia