There was an almond tree at the corner of the elementary school playground when I was a kid in Oregon. I was just talking about that tree on TEG a week or so ago. It would bloom but not set seeds. I knew it was an almond, I guess, because we had family in California. Plenty of almonds there.
If pecans are too large, maybe almonds ... but, I wish more people would go for hazelnuts here. The walnuts across the road from my home are useless but, I know, hazelnuts mature properly.
Perennials, trees have geographical needs. I have a garden with a Klamath plum on one side. I have been there nearly 15 years. The tree is quite large for that type. It flowers profusely every spring. I bet that I wouldn't have been able to fill a 5-gallon bucket half full if I would have collected ALL the plums off that tree from every year that I have been there. There are, maybe, 12 plums each summer!
Our European plums do well here. What gives? The tree is named for Klamath in southeastern Oregon. That's about 500 miles south, as the crow flies. It's a high elevation, gets plenty cold there and probably about like here. There is a local story in that part of the world that bear tracks are deeper when the plums are ripe. I think I figured it out ...
The blooming season is triggered by the hours of sunlight and darkness. The flowers show up too early and frosts damage them, year after year. That tree is too far north! Plums are deep within the branches and very few.
Steve