There are a lot of species that may be misinterpreted as a shrub, i.e. a Hazel tree https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/br... is dense, and forms many smaller straighter branches shooting up in parallel... could easily be mistaken as a shrub as this next pic shows https://cotswoldtrees.com/hazel-corylus-avellana/ .

Still a tree though, and all trees are good trees.