I spotted this hornbeam tree or Carpinus japonica growing in the wild (Ikuta woods). It is considered to be a good urban tree to plant see this link. The hornbeam tree slowly reaches a height and spread of 20 to 30 feet. It will grow with an attractive open habit in total shade, but be dense in full sun. The leaves are serrated; the tree has muscle-like bark – smooth, gray and fluted. The fall colour is faintly orange to yellow and stands out in the landscape or woods in the fall. Brown leaves occasionally hang on the tree into the winter.