Slightly OT ... loss of trees

[Jethro]

Our neighbour (finally !!!!!!!!!) decided two willow trees in his garden (which lent over ours, so we got the leave and branches) had to go. So today some very well equipped guys attacked them with chainsaws and left

2 poisoned stumps. Chatting to the gaffer he reckoned they'd chipped about 2 tonnes, and were going to take the trunks away as logs ... I'd guesstimate about another 3-4 tonnes of wood.

Clearly feeling he's onto a good thing, our neighbour also got a silver birch, about 15m tall taken down from his back garden.

So, sighs of relief all around for the insurance.

However, I vague recall that such sudden changes in the water-absorbing capability of the soil can cause problems ... anything I need to watch out for ? Said willows were about 8m from the edge of our property, and about 10m tall ....

[Harry Bloomfield]

Jethro brought next idea :

We ourselves had two very large willows and around the same distance from our house. The were originally planted to help dry up the soil, a foot or so of soil on clay - which would always become very boggy in wet weather.

I cut them down about six years ago, fed up with their mess of leaves everywhere and the gutters they blocked. There have been no issues since, apart from the garage base started to flood more than ever. In the six years I have gradually improved the drainage and a couple of years ago managed to stop the garage flood issues.

[Hugh - Was Invisible]

You can get heave of buildings on shrinkable clay when large trees are removed. When I removed several leylandi at one house I reduced them over 3 seasons but they were much closer.

I doubt whether you are at much risk even if on shrinkable clay. Dealt with dozens (hundreds?) of claims for subsidence but the only claim for heave I ever saw was a new estate built on a cleared wood without allowing time for the soil to adjust to the lack of trees extracting moisture. Cost a lot as I recall.

We have a 60 ft high ash tree with a TPO about 40ft from our house with big roots under our lawn to the house. Scary until I found we are on piles. (The house, not us)

[Jethro]

Having done a bit of research (i.e. google) it seems the key question is "which came first: house or tree ?". A quick gander at rings on the willow stumps indicate they are not as old as the house (1960), presumably they were planted by the developers or the first houseowner. This is the best state of affairs, as the houses foundations were built into the soil before the willows sucked the water out. It seems things are more problematic if the house was built after the trees were planted, which makes sense to me.

On a related note, would heave be more serious for a house than a bungalow, given the bungalow will have roughly half the weight to support ?