The columnar hornbeam is narrow upright deciduous tree 30' by about 15' but not really "columnar" in shape. Shape is usually more upright oval being much wider at the base but still pretty narrow and good for parking lots and other areas with limited head space. Develops a short trunk with multiple leaders. Fall color is a pretty yellow.
Buds are long brown and appressed against the stems.
Male flowers overwinter in catkins, 1-1.5". Female develop large conspicuous bracts that are easily seen when the plant is in fruit.
This is what they look like in mass on the tree.
Fruit in a small nut inside the large brown bracts.
Misidentification: other hornbeams maybe.
Location:
Santa Cruz: 701 Pacific Ave, Just off Pacific across from CVS and Trader Joes is a small alley next to a parking lot. Follow the alley. Some of the nicest ones around.