Neighbour refuses to cut down a tree which we know will causing subsidence

[Yellowstickerstalker]

Next door have a tree which is an ash, and our gardener told us that it would cause subsidence and it needs to be felled.
That was almost a year ago, since then we have an immensely frustrating backwards and forwards dialogue where he promises to do it, then changes his mind, then prunes it, says that is all he will do etc etc.
A few weeks ago we had the garden fences replaced and the intervening wall collapsed - it was obviously the tree had which had caused this.

After ringing me in a panic 👀on my advice my partner called next door round and showed him. He seemed to at least 'get it' and they shook hands on his promise to remove it. He has since cut it down significantly but not enough to stop growth. DP has just tackled him again and he said he is not doing anymore, my partner pointed out they'd agreed but that didn't land.

Annoyingly DP said 'yellow sticker' won't be happy, which I am annoyed about as I have deliberately tried to avoid getting involved. Next door is a total misogynist - I believe his initial stubbornness to do anything came from the fact our gardener is a woman. TBH, I have enough battles to fight, SEND kid who has been let down at school, EHCP review battles, it's constant and do not want to get involved.

So, my question is, does anyone know what we should do next please? We may move in the next few years, I don't want to be in dispute ideally. Can the council get involved if it only really poses subsidence issues for our properties? I have thought about getting an arborist round but I doubt we'll get access to the garden. The guy we are dealing with is the son of the owner, who is elderly and in her 90's and has also always been quite tricky to deal with so I have no faith in them seeing the light. Is there a quick and easy legal route which might only cost us a few hundred?
Thanks, for context they don't use the garden and have plenty of other trees, so I know it's not sentimental. That has never come up. They just don't seem to be taking it seriously even though a wall collapsed. They have also paid nothing towards removing the remnants of the bricks, which they also promised to do.
Thank you for reading!

Our surveyor said it would be a bad idea to cut down the tree in our back garden that is quite close to the house. I assume this is because the roots will die and there will be air instead of roots and that is more likely to cause subsidence than leaving the tree.

I wouldn't do anything on the say so of a gardener. Get proper advice if you're concerned.

I agree. A gradual cutting back was suggested to a neighbour who had three huge leylandii which would have caused heave.

Don't listen to anyone but a subsidence specialist. You're assuming a lot here.

You don't even know if you have subsidence?!

By the way, chopping down mature established trees can caused subsidence and ground swell. I have experienced this personally when cutting down 5 conifers. My whole fence and shed went on the wonky. Significantly.

Yup, as i said upthread, someone on the same estate to me, but not close thank goodness, removed a mature oak from their garden and ended up needing to have the house underpinned. this was some 25 years ago but its history continues and is stated every time it sells.

We had issues with neighbours landscaping works and five large trees along our boundary. We contacted the council when they dug out roadside laurel hedging about 100 m in length. They did come up to look but the law was that unless we kept livestock in our garden, they could not force reinstatement. They were concerned they had changed the landscape of the village however.

They did however raise concern about their lack of tree maintenance and insisted on works from.a public protection perspective. Trees were not under TPOs. The works were minimal and not as you have described works undertaken by your ndn.

You cannot force him to cut down the tree. You are lucky he has undertaken works unlike our horrible neighbours.

There’s quite a lot of rubbish on this thread - mainly because people don’t know what subsidence is. DH is CEng FIStructE and I have listened to this stuff for years.

Subsidence - the ground beneath the house shrinks or is washed away. Shrinkage occurs quite a lot in clay soils. Washing away is often gravel soils. Shrinkage is caused by lack of water in the soil so it has less volume. The house then subsides into the void. Hence subsidence. The lack of water in the soil is often caused by tree roots drinking it to keep the tree alive. Hence the concern of the gardener! This doesn’t necessarily matter when a house has 2m deep foundations (for example) but it certainly can where foundations are inadequate or shallow. In effect the property is let down by inadequate foundations for the soil conditions. Cracks will appear which are typical of subsidence. They will be noticeable.

So, what soil is it? How deep are the foundations? How old is your property? How close is the tree? How old is the tree and is there any sign of damage to the house? I haven’t looked up root spread of an ash, but you could. Roots can also get into drains and crack them. This can wash away soil or lead to expansion of soil. See below.

Serious subsidence damage leads to underpinning. Less serious damage is repairing and possibly pollarding the tree so it needs less water. Therefore the next door neighbour might have done the best thing.

Lastly, removing a tree drinking a lot of water can affect the soil. Where does the water go now the tree isn’t drinking it? This can be a vast amount of water.

Heave: It can, and sometimes will, stay in the vicinity of the ex tree and enlarge the volume of the soil. Often clay soils. The soil expends, and where foundations are inadequate, walls are pushed outwards. This is called heave. Cracks appear, but different cracks. It’s a completely different process going on in the soil and how it affects a building is different. Essentially subsidence is collapse and heave is pushing the walls upwards and out of alignment. Obviously both are problematic.

A structural engineer will know what is happening by inspecting a building. However a partially cut down tree might be better than a totally removed tree. If you are worried, your property can be monitored but this is normally done if cracks appear.

Do not say anything to your insurance company! you have no evidence of anything wrong! You might need to ckd st some point but the tree is not yours and you have twin steps to protect your property. As yet, there’s no claim. You don’t have yo declare concern about a neighbours tree!

The wall - probably had no foundations. How old was it?