Apple tree with rotting trunk.

It looks like it rotted where someone once cut off a very large branch.
Apple trees seem to rot quite easily inside once a wound is opened to expose it to fungal attack.

That's the danger of cutting off branches more than an inch, or at most two, in diameter.

Pruning needs to be aimed at anticipating the tree's growth and removing potentially troublesome branches before they get too large and pose a risk to the tree health.

Being in a damp climate and shady location probably encouraged the large wound to rot inside, but the edges of the wound appear to have walled-off the rotting (my Blenheim did that with a canker attack).

You'll be amazed at how resilient some of those old triploids can be. I see no reason why your tree can't live another few decades or more - especially as the tree has healed the edge of its wounds with a curved rim of bark.

If possible, I'd let it gradually lean over (gradually - don't let it fall over and break off suddenly) to touch the ground, where it will root itself in if given time. It will then grow one or more new "own root" trees up from side shoots of the old trunk.
The original Bramley tree fell over, but its high vigour allowed it to regenerate. the same is supposedly true for certain other old varieties - mostly vigorous triploids.

Vigorous triploid varieties such as Bramley, Blenheim, Boskoop, Gravenstein, Gascoyne's, Hambledon Deux Ans and certain others are like terminators; you may knock 'em down or cause them serious damage, but they'll usually come bouncing back.
As long as the tree has enough vigour to send out some long new shoots, it has enough vigour to come back from near-death experiences. I think that some old trees are removed as "lost causes" when actually they are tough and vigorous and can be regenerated by good management and pruning.

Yah! Let it re-root, and I'll take a sapling of it to let it carry on it's legacy over the mountain

Thanks FB, The wound is firm to touch, just a bit damp at the base. Its been falling lower and lower over the years and very little of the trunk is touching the gatepost. I'll let it continue its journey down to the ground! There are several apple trees here that have blown over completely and had to be removed but the stumps have regenerated and look better than they did before the accident!

Chris, if you want some side shoots of those you're very welcome!!

I also see no evidence of canker or woolly aphid, which are major pests of old trees.

How do the branches look for canker, scab, mildew or woolly aphid?
Are they as free from disease as the trunk?*

*
Obviously the trunk has rotted, but it's not the tree's fault that someone lopped off a large chunk. Since the inner wood of a tree is basically dead, it is easy for fungi to invade.
But as I said: the living outer part of the trunk (bark and cambium) appear to be very healthy.

Here are a few more photos. Pics 2 and 3 are either side of the main horizontal branch/trunk.

Here is a little apple I found at its foot

This poor old apple tree has just received another body blow, literally. An equally old tree, in my neighbour's garden has been toppled by the snow and is resting partly on the ground in my garden and partly on this apple tree, (tentatively identified as Gascoyne's Scarlet).
I expect my neighbour will cut his tree down, but some of the branches are tangled in my tree and will stress the damaged trunk. Is there anything I can do to salvage my tree? Apart from the lower branches, it will be a ladder job - and I don't do that!


Next doors tree had really nice apples too - most of them fell in my garden Can I take cuttings at this time of year?

Wedge several wooden props under your tree - a couple under the trunk and one under each main branch.
The props will take the weight.
Any damage it receives it'll probably be able to re-grow.

Judging by the really long-reaching slender habit of the branches revealed in these new pictures, I would strongly suspect Gascoyne's Scarlet, or a small chance of a now-forgotten variety no longer known, or an outside chance of a Gravenstein.
Gascoyne's Scarlet blossom will be slightly towards the pink-tinged end of the spectrum, while Gravenstein is more towards the white-tinged.

Perhaps now would be a good time to remove some of the topweight.
This may then encourage new branches to form lower down nearer the ground and you could gradually remove old high branches and let young low branches take their place.
If done well over the next few years (remove about a quarter of the canopy each winter), the tree will have an entirely new lease of life like planting a young tree.

I'd favour thinning cuts over heading cuts. (i.e. favour removal of several medium-sized branches rather than prune the tip off all the branches). This will reduce the "witches broom" effect of masses of dense new growth which tends to arise from heading cuts on older trees.

->

Thanks FB. The main trunk is firmly wedged onto the fence post - even more than it was earlier in the year. I'm not sure how I can prop up the rest of the tree as its way above my head If it stays fine tomorrow, I'll cut out as much as I can reach of next door's tree to take some of the weight off it. You can expect more photos then!

As an aside, I have an apple tree that has regrown from a stump after it fell over and had to be cut down - and its fruited. You have to admire their tenacity.

If the tree is a variety which is naturally vigorous and healthy, and was grafted onto a strong rootstock, it has a good chance of regrowing.
It's quite possible that even if your Gascoyne snapped off close to the ground, that it might re-grow as in the picture I posted. There are a couple of very old presumed Bramleys within about a mile of me and they have regrown several new trees from the base. Each is now a ring of trunks at the outer edges of where the thick old trunk once was (which is now just a hollow in the ground!

Incidentally, if your Gascoyne did snap at the lower trunk, I'd be inclined to leave the broken piece untouched because it'll probably still be attached on the underside and will still receive sap from the roots on that side.
If you removed the broken trunk immediately it might be too much trauma in the same way as taking more than a quarter to a third off an old tree can lead to shock. After a few years it may then be possible to remove the broken piece.

What rootstocks would they have been using in 1940, FB?