Thanks so much for your reply
The tree is at a rental house but I'm going to check it out tomorrow. If it looks beyond repair, I'll cut that one off at the base. The other two trunks look great

Hi John, found your mssg when I scrolled down on my notification email.

I have 2 large Robellini's, 1 in front &1 in back. They've been in the ground 12 yrs. 1 is a 4 trunk & 1 is a 5 trunk. So far, I've been lucky & have not had any loss of a trunk. I've noticed around the 'hood other people's Robellini that have had a trunk or 2 die off. I think once they start to go there is no hope for that trunk. I learned from a landscaper those trunks are actually independent of each other. They don't share the same root system. If you lose one, depending on the reason for the loss, you may not lose them all. If there's a pathogen in the soil, (fungus), then you probably will lose all of them. If one died from insect infestation & it didn't get to the other trunks, you're probably safe. If one died from one of our colder winters, the ones that survive will probably continue to grow. That's my take on it. Sorry you're losing one.

Did you message me? I'm getting a notification you did but I don't see anything.