Barking!

With a Tiny Tuesday theme of ruff, I'd have been barking to pass up these specimens on my brief lunchtime walk. (But I can't otherwise justify the canine puns!)

The difference between the various types of bark was very striking; I'm afraid I'm not sure what they are other than I assume silver birch is the first extra. It was good to take notice of something different.
Thanks to Incredibish for taking the lead this month.