Barking Up The Wrong Tree

[Humakt]

Chaps.
I need to call on the collective NBC hive mind.
I'm making a bird table. I'm making it so that it looks like a tree. You know - the post still has the bark on, the table is also made from dropped wood, etc.
But the roof.
I want to keep with the 'natural' look so thought I'd make the roof from a piece of bark.
And that's what I'm looking for advice on.
Which tree will yield the best piece of bark that I can harvest? I'm looking for a piece about 18" square (though I suppose it could be done in two, maybe three, pieces). Birch seems like an obvious choice, though I will need a bark with a bit of thickness to it for durability.
Is this even the right time to take such a piece of bark (and is there ever)?
I should highlight that I live in the south east UK, so limited to trees available in that area and climate.
Thoughts and advice appreciated.

[FishyFolk]

Well, birch is water proof...

[Woody]

Birch is definitely a good choice , preferably from a recently felled or fallen tree as then you can harvest the inner bark too ( making for a thicker layer) without worry about the damage .

On some trees, the outer dead layers peel and drop off, revealing the inner layers of bark. Shedding or peeling bark is characteristic of trees such as the sycamore, redbud, silver maple, shagbark hickory, birch, and Scotch pine.

Now for the tricky one...
I'm not 100% sure but I think that cedar bark can be sometimes loose on older trees, and removing it would not damage the cambium layer. ( Better check that before)
With cedar the mulch can be weaved , or if in lumps (usually pretty thick) , they can be glued ( with pine sap for the natural approach) together to form a thick plank.

Either way is better to not remove bark of a living tree , especially from the south/southeast facing part of the tree.

Hopefully this is a helpful post and I look forward to seeing the fruits of your toil on this great project.

ATB

[Pootle]

18" is pretty big. Maybe you could use strips of birch. Say 18" × 9" overlapped like three long horizontal tiles?

[Humakt]

Done!
The main post was from a bit of hornbeam. The baseplate was from a tray I bought at a bootfair for the princely sum of 50p! Then the side posts made from some hazel I scavenged and then...the roof.
It was topped with a piece of ply that I stained and put some preserver on. I did originally cover it with some pine bark (just couldn't find a decent sized piece of fallen birch). It looked the part. But the first visit by a squirrel and a piece was missing. So the other day I was in Poundland and they had some garden border edging made from willow staves. So I bought some and used that for the roof. Far more durable and still looks the part.
And then embedded it all in a bucket of concrete.
All in, this couldn't have cost me more than a fiver at the most!
As well as the squirrels (inevitably) it's been christened by blue tits, great tits, coal tits, chaffinches, green finches, pigeons, doves, sparrows, used as a lookout post by a robin, even a jay paid a visit. And it's been given a good stare at by the garden wren.
Here it is...

[Woody]

That's brilliant! Lovely natural looking bird haven...
Well done Humakt !
👍

[Pootle]

That looks great. And good visitation too!
I try not to attract birds as we have two cats and it feels like we're luring them into a trap.

[Tigger004]

I don't suppose you would want to thatch it, they look good ?