Mouldy trees

Sad times - the trees in the South Lawn are not well.

Both the Laburnum & the Cherry have struggled this year. 

We conjectured the cause:

• Not enough light?
  The cherry in particular is hard up against the tall South Hedge. Maybe that's why all the leaves are up the top?
  
  
• Water logged?
  We're sat on a hill of clay & the garden was sopping over Winter. But then again it's been a long, dry Summer & there's no sign of a late recovery.
  
  
• Insect attack?
  We have a lot of red spider mites kicking around. I've heard gardeners whinge about them, although I've no idea exactly why.
  
  
• Age?
  Are they just old? The photo of the house we have from 1974 shows a blurry yellow smudge which implies the Laburnum in & established. If it was planted when the house was built, it'll be about 65-70 years old now. Not ancient then, heading into its twilight years.

I need a Doctor...

We've got more questions than answers. We need a pro.
So when Richard the tree surgeon came to quote for lowering the Big Beech Hedge (another story, another day), we asked his advice.
On the Cherry, he spotted some extensive bark damage on a low branch. Could it be birds...?

But then he spotted this:



Bracket fungus, right at the base of the trunk

Pants. It's right at the base of the trunk. He says it's pretty terminal. Sad times :(

As for the Laburnum, he wasn't sure.

He said he'd trim back the dead, dying & diseased, then we could see how they got on.

1 month later...

Oh dear. Both trees are sporting new & 'interesting' mould:



Ewww! Do you need ice cream with that?
Something gelatinous at the base of the Cherry.

A different mould, covering the end of a cut,
but also bursting out all the way up the Laburnum...

Looks like both will be hitting the log pile soon :(

Anyone got any tree replacement advice?

Is it a bad idea to plant healthy new sapplings in mouldy locations?