Sanchy
The tree dream has two applications as shown by the use of the word' times' rather than' years' and the many references in Ch.4 to God's Kingdom;
Seven times does not mean seven years for the word time means an appointed or definite time or period. If literal years are meant then the appropriate word would have been used to say just that meaning. The periods have afar greater application because of the reference to God's kingdom or rulership in connection with the humiliation of Neb.
The dream's application to Neb's humiliation proved God's sovereignty and that all rulers are subject to a rulership greater than theirs thus in context with the book of Daniel showed that God's kingdom would be an indefinite one. We can all appeal to authority and that is what one does when one uses exegesis because must research widely and consider the opinions of others.
In the case of the interpretation of the tree dream, there are a wide range of opinions but I embrace that as such various views allow one to reflect on these views and then form one's own view of matters. In short, one does his or her own exegesis or accept an eisegesis from others if that is the preference.
scholar