Crown Gall on Ornamental Cherry

Five years ago I moved to a house with an neglected garden featuring one ornamental cherry. It's now about 3.5m high. I've been struggling with it from day one. First it had canker. I removed affected branches in summer and sealed the wounds. Now it seems to have a crown gall, a corky lump 20cm across at soil level against the trunk. The tree's leaves are slightly curled in and have lost their gloss. It seems pretty sick. So my questions are:

1) Is it definitely crown gall?
2) If so, is there any way to treat it? Is it too late?
3) If I have to take down the tree, what can I do to protect my fruit trees?
4) I've read the bacteria can live up to five years in the soil. Is there anything I could plant in its place, other than grass?!

Any help very much appreciated.

Re: Crown Gall on Ornamental Cherry

Reply from Nicola

Hi Anita - can you add any images of the affected parts? It helps sometimes to see an image of the disease to identify it. Thanks Nicola

Re: Crown Gall on Ornamental Cherry

Reply from Anita Sullivan

Thanks for your reply, Nicola. Here are some photos of the sinister lump. XAX