The logical representation of UI controls is called as Logical Tree. Logical Tree structure represents the hierarchy of UI controls and elements in WPF. Logical Tree doesn’t include inner controls of UI element. For example, Window contains StackPanel and StackPanel contains Buttons the Logical Tree can be represented as below
The Logical representation of UI controls with its internal controls is called as Visual Tree. Visual Tree contains same elements the Logical Tree contains but it also contains elements or controls which are internally used to create the element or control in Logical Tree. In short, you can say Visual Tree contains all the elements the Logical Tree has with its template of each element. Please have a look on Visual Tree of above created Logical Tree.