Kat - Jerusalem Thorn does not like water. Consider that it's a desert tree. It's possible that with all the rain, your tree might have received too much. A fungus is possible, especially now that we're into the rainy season. You might try a mild, general purpose fungicide.

Thanks for the info, Ricky. But I've been having a problem with this tree for a year now, so I don't think it's the water. I'll have to check out a fungus. Thanks again. :o)

Its hard to say without seeing it. JT is a type of palo verde, the most moisture tolerant one. It can tolerate our high rainfall in summer but needs a well drained soil and good air circulation in full sun. But they do seem to be short lived here, 10-20 years is average.

Is there lawn underneath it? Some trees are ultra sensitive to herbicide use under their canopies such as those in weed n feed products.

Thanks for the info Eric. It is in full sun and there is a bromeliad bed under it and grass around that, which I have used weed and feed on. I will be more careful not to use it there in the future. No other trees are around it. It is over 10 years old now though.