The line between whether a plant is a "tree" or a "shrub" is sometimes very thin and quite blurry! We use the following criteria to decide which type applies to a certain plant:
Cedrus deodara 'Feelin Blue'
Cephalotaxus harringtonia 'Duke Gardens'
Cephalotaxus harringtonia 'Fritz Huber'
Cephalotaxus harringtonia 'Gold Rush'
Chaenomeles x 'Bonita'
Sideroxylon thornei, Swamp Buckthorn