A prized acer palmatum Shishigashira suddenly developed some sort of wilt.
It's 15yr old at least, about 8ft tall.
Its position by my front door tells you how much I value it.
It has done fine over many years.
I just noticed yesterday that half the plant is essentially dead.
The plant branches just a couple inches up from the crown.
The larger portion (naturally) has apparently abruptly died.
On closer inspection, there is swelling/fissuring of the trunk just above the bifurcation.
I cut off the diseased portion as close to the bifurcation as I could.
But I see in the transection of the trunk still a large area of darkening.
Is the remained portion of the tree doomed?
Is there anything I can do about it?
Here are a bunch of pictures.
#1 is a shot of the whole tree.
#2 shows the lower 1/2 where the tree divides into a healthy and dead half.
#3 shows the withered dead foliage on the affected half.
#4 shows the cut off portion.
#5 shows the swelling at the bottom of the affected stem as well as the discoloration of the wood.
I don't have any good news or even words of encouragement.
The image showing the base of your plant intrigues me. I don't see any normal buttressing that one would expect on a plant that age - 15 years plus. You should do some excavation (a water blasting to wash soil away from the trunk and upper roots) and see what one might see. Possible girdling roots would explain some problems.
Another disease of maples is the dreaded Verticillium Wilt. You should take the portion of your plant that you have removed to your Cooperative Extension Service for diagnosis of the problem.
I am a little confused by your description. Is the division at the Base of the tree? If so maybe the live 1/2 is a sucker from the graft union which has taken over. Were the both branches, the dead one, and the live one the same leaf color and pattern? Just a wild guess, and maybe unlikely given the age and size of the tree
No, the trunk splits into two halves just an inch or two above the crown.
Both halves show typical Shishigashira foliage.
The remaining half still looks good a few weeks after I cut off the other half.
Time will tell.