A garden tragedy

I've been keeping an eye on this all spring, and hoping things would be fine, but it's not looking good.

Last spring I bought a gorgeous Kamagata Japanese maple from Lucile at Whitman Farms. I adore this tree and it was gorgeous last year. In winter I treated it just like my other Japanese maple: Lots and lots of mulch and burlap wrapped around a "cage" constructed around it. I did not close the top of the burlap and I'm now thinking that was the fatal flaw in my plan.

The bottom third of the tree has leafed out nicely, but the top is not looking good. Leaves only here and there, and what appears to be a lot of dead wood. I've not trimmed anything out of it because you never know what can happen. And now I see some of the leaves on the top half are all wilty.

I have no idea what is going on but I'm just sick about it for a lot of reasons: it wasn't a cheap tree, I don't want to have a huge hole there all summer and Lucile is so incredible I feel like I've done wrong by her tree.

I'm going to e-mail her and see if she has any words of wisdom for me, but I'm afraid it might be a lost cause.