On Friday, June 14, 2019 at 10:28:58 PM UTC-4, DerbyDad03 wrote:
On Friday, June 14, 2019 at 10:21:41 PM UTC-4, Clare Snyder wrote:
On Fri, 14 Jun 2019 19:04:46 -0700 (PDT), DerbyDad03
wrote:

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?

Yes - it is pressure treated wood and the marks are from the"wheels"
that drive the wood through the treating process - and help the
treatment penetrate deeper into the wood

And yet we don't see the marks on *all* pressure treated wood. At least I
where I live, even on wooden docks. Maybe it's a west coast thing?

At least *not* where I live...