Fraxinus excelsior (European) Family: Oleaceae.
Fraxinus ornus
The scientific name is Acer negundo. I found this on http://www.wildflower.org/plants/result.php?id_plant=ACNE2
The Mountain Ash is Sorbus aucuparia. I know of no tree called the Rocky Mountain Ash.
Fraxinus americana.
The name would be Fraxinus excelsior.
Sorbus americana
The name would be Fraxinus americana.
Rowan or Sorbus aucuparia.
It depends on the species but beech trees are members of the genus Fagus. For instance, the American beech is Fagus grandifolia.
carbon
The scientific name of a tangerine tree is Citrus reticulata.
Another name for the Rowan Tree is the Mountain Ash. It is known for its clusters of bright red berries and is often associated with various myths and folklore, particularly in Celtic traditions. The scientific name for the Rowan Tree is Sorbus aucuparia.