ants in my tree

I was taking a photo of a rowan tree I have to find out which variety it is and while doing this I noticed a lot of ants to-ing and fro-ing from the ground to various branches. could they be doing any harm?

 

No. They will be farming aphids and collecting honey-dew. Watch them and be fascinated.

 

hi LG & H
how coincidental !! i was just about to post the same question!!!

just to be certain h , my rowans were only planted last november and were purchased from a tree specialist, so are about 18 centimetres trunk circumference, so they are not very, very young, are you sure in these circunstances the ants could not be damaging , because all of the tiny leaves on both trees are showing a browning of the leaf tip , i am just about to post this problem so please advise on either this post or the new one.
cheers.
Gordon.