I think you found the problem, especially since the Fuerte recovered when you slowed the watering.

What do you mean by "raised bed"? How high is it, and how big? Avocados have a shallow root system at the surface of the soil and going down about a foot to two feet, and those roots must stay cool. Raised beds usually warm the soil. That might be a problem. The roots may also have trouble if they cannot spread out, since they stay so shallow.

Avocados hate having their roots disturbed. They need a lot of water as well. You should mulch the trees heavily, and don't remove the leaf litter under them.

They also lose many of their old leaves once a year in May/June and put out flowers and new fresh leaves. Your trees may have been going through their normal cycle of leaf drop.

Be sure the trees don't get sunburned on the trunks and branches. If the branches turn brown on the top they are getting too much sun. Rig up some shade for them for the rest of the summer if this is the case. Or you can paint the branches and trunk with white latex paint.

Good luck with your trees- you picked all of my favorite varieties. I almost lost all of mine when I planted them because I failed to water them enough and I did not mulch. I lost the Fuerte- but saved two Hass.

Renee

The raised bed is about a foot high and 5 feet in diameter. I have very poorly draining clay soil, so I make use of raised beds whenever I can. Without the raised bed, I'm sure I would have a serious root rot problem.

I also have a Reed in a different location and it seems to be doing fine.

I'll try the shade, these three trees get full sun from sunrise to sunset so that might cause issues since they are already stressed.

The water softener definitely is a problem because the salt is causing root damage. Make sure you water the area around the tree as well to dilute the built up salt content and see if things get better.

As for the raised bed thing, to make the roots go deeper than normal, make sure you drip water close to the trunk. I have a Hass that is in an area about the same but not in a raised bed. We also mulched with gravel to prevent weeds and never remove the dropped leaves. Avocados are heavy shedders, but not until the tree looks bald.

Good luck.

How about if one is using potassium rather than sodium for their water softener?

I have a 12 year old Fuerte that is not producing. It flowers, but the fruit does not set. Do you think simply more water and mulch would solve this problem? I am thinking of cutting it down and planting a Haas (second choice fruit).

I had the same problem with my Fuerte. My two Hass avos produce like crazy.