From the Talmud in tractate Rosh Hashanah it appears that there is no obligation to recite the blessing; rather, "one who goes out and sees"—meaning that if he went and saw, then he recites the blessing. This is exactly like when a person wants to drink—he has to recite a blessing. But we are not talking about a case where one must go and search for trees and recite a blessing over them (and it would be similar to someone looking to drink a cup of water in order to make a blessing). Of course, that is nice, but it is not an obligation at all.
Does the Rabbi agree with what I said?

In the simple sense, you are right; that is also what emerges from the plain wording of the halakhic decisors. However, I saw that in Minchat Asher he wrote that this is an obligation that takes effect upon you from Nisan, except that the blessing should be recited only if one sees trees.