On our recent trip to Oregon we walked along the docks in Astoria, right
near the original Bumble Bee Tuna cannery on the Columbia River.

All of the wood on the docks, the railings and even the railroad ties
look like the following. There was a mixture of old wood and new and it
all looked like this:

https://i.imgur.com/IOgfmsB.jpg

Do the "dashes" serve a purpose? Are they perhaps marks from where
preservative was injected?

If you are ever in Astoria, OR stop for a snack/meal at Coffee Girl, right
inside the old cannery on Pier 39. They still serve their customers at
the original counter that the Coffee Girl used to serve coffee to the
cannery workers. Great food and greater coffee.

https://www.google.com/search?q=coff...toria&tbm=isch

Outside the cafe, but still inside the cannery, they've created
a very rustic museum highlighting the history of the cannery, with
boats, cannery equipment, lots of pictures, etc. You can go into
the power room and see a few different generations of the generators
and other power distribution equipment. It's a pretty cool place.

https://www.google.com/search?q=cann...toria&tbm=isch