This has been identified below as Prunus avium (mazzard or sweet cherry). One of these cherries came into bloom last week (end of March) in the west end in Vancouver, BC, two came out a few days later, and one is on the way. Two are older relatively large trees. They're round in shape, green leaves, with pom poms composed of quite small single blossoms. Because the first one I saw is on a property the same distance but the opposite side of the entrance path as (what was) a Tibetan Paperbark, I wondered if it might also be the same, so I've included a photo of the bark. In the first photo, it's the tree on the right. I'd like to know what tree this is. Thanks.