Joe...this is a tough one for me. Could this be left-over damage from a frost you had in February? Did this get sprayed with a herbicide? Keep us posted...

I'm not an expert, so hopefully someone who knows more will correct me if I'm wrong. But--that looks just like the damage I see on some of my young fruit, which I believe was caused by recent winds. As the branches thrashed around, some of the little avocados got abrasions and bruises from rubbing against branches. Also. avocado trees may set way more fruit than they can ripen, and will drop lots of immature fruit until they get down to a manageable quantity. For instance, my tree may set 6-8 fruit from one cluster of flowers, but it will drop them until there's only one or two left. That may be all that's happening with your tree. Does it still look like you have a good amount of undamaged fruit still on the tree? If so, I would just give it time and not worry about it.

Well, it might take a couple/few years but from what I've read, these trees are tough. You have a very well established root system with a tree like that so it might take a little structure pruning along the way to develop good form. Usually when a tree comes back from the stump, the growth tends to be on the wild side with long shoots and huge leaves, but I'm not an Avocado tree guy so can't really say for sure. Usually with structure pruning is you just keep an eye on the growth each year and do a little clip here and there so the tree assumes nice form. What that is for Avocados idk. Good Luck! :o)

Actually on closer inspection - this had to be earlier damage. Not sure about the policy of the nursery you bought from, but they shouldn't have sold that IMHO unless it were in a 'discount bin'. L Clark is right, it could probably seal it off...but if the tree was handled that poorly at the nursery I would be inclined to wonder what other ways it might have been mishandled...like having a circling, knotted root system that will fail 5, 10 or even 15 years down the road. The more I keep a keen eye on plantings around my county and hear reports like this here...the more inclined I am to say, people should be steered away from planting large trees like this unless they come from an absolutely stellar nursery. This place, for example: http://www.raemelton.com/ grows everything in a field and only digs on purchase, with a marvelous machine with a gigantic U shaped blade. The one tree I got from them (they generally don't carry rare enough stuff to snag my interest) established perfectly well. But the kind of trees that have spent their life in a big wired up burlap bag and a feeder hose attached? I'll pass! Better to plant a 4-5' container grown, not pot bound oak - so that means it's going to be in a big 5 gallon pot at least - and properly loosen and splay the roots on planting. It will probably catch up and exceed a big B&B tree like this in 5 years.