Last week I was walking in a brush filled tributary of Soldier Creek when I noticed a tree that I couldn't identify. It was somewhat familiar, but I could not place it. Was it invasive? Where did it come from? Why was there just a single specimen? I made a picture and took it home to look it up. Crataegus douglasii. Black hawthorn.
The specimen I'd noticed is native to Utah, but was outside the range map for the species. It made me curious, so I went back the next day and surveyed from the tributary's confluence with Soldier Creek to the first main branch of the canyon, a distance of about 1.5 miles. I found eleven, including the one from the day before: Ten of them were alive and one was dead. It makes up less than one percent of the riparian vegetation, but it certainly seems well established. Perhaps we should extend the range map?