Chances of heave if willow is felled?

[boris360]

Hi all,

 

I'm looking for advice on whether I need to get an arborist's report before a willow is felled.

 

The willow is at the bottom of my garden.

The distance from my garden retaining wall is 21 metres.

The tree is downhill from the house on a slope of approx 7º.

It's on clayey, loamy soil (I think).

The tree is mature.

The tree was there before the house was built.

The house is 14 years old.

 

I've spoken to a structural engineer, the council tree advisor and also a tree surgeon all of whom say the tree is too far away to cause heave or any other issues. I thought I'd ask here because I expect there are more knowledgable people on this type of issue.

 

I've read about heave on these forums and also about how bad willows can be hence my caution but I'm not sure how far away a willow can be before it's no longer a problem.

 

Any advice would be much appreciated. Thanks.

[HertsWood]

Heave is dependent on the soil makeup ie clay content. You need an Arb consultant who specialises in this area to advise you. Call the Arboricultural Association to find out who is your closest consultant. Robert Kennedy & David Dowson are 2 I know - they will travel nationally.

[Mick Dempsey]

It's too far away.

Why do you doubt the TO and the structural engineer?

[Ian C]

It's too far away.

Why do you doubt the TO and the structural engineer?

 

Same as mick

[Wood-be]

I'm no structural engineer but have seen the effects of trees being felled to close to houses. That tree is far enough away to cause.any damage to the house or wall. The only issue there will be is the increased water content to the soil after the tree has been felled. Especially during the summer. Nothing to worry about really.

 

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[OakStag]

The willow definitely looks to far away to cause any heave. Roots spread approximately 1.5 to 2 times the spread of the crown maximum.

[phirow]

Why not pollard the tree?

[boris360]

It's too far away.

Why do you doubt the TO and the structural engineer?

 

Thanks for the replies.

 

The reason I'm not relying solely on their advice is I don't know how knowledgable they are on this specific issue. Also, the conversations I had with them regarding this were brief and they didn't really mention the soil which I thought was crucial (as Hertswood mentioned).

The tree looks closer in real life than the picture suggests but it's bang on 21 to metres from the trunk to the wall.

 

Regarding Pollarding, this is what I got the tree surgeon out to quote for but he seemed to think it was a waste of time. He suggested leaving it alone or felling it. My reason for wanting to do anything at all is that the tree has become so big and is constantly dropping branches and is a pain to maintain. On a side note, I wonder how healthy the tree is because when it's in leaf, it has more of a yellowy look than other willows that I see. The leaves have black spots on too which I think was identified as anthro(something or other) on another thread on here. That also makes me wonder what the implications are if the tree dies naturally.

 

To the people that are saying it's too far to cause a problem; are you saying this because it's too far given all my particular circumstances, or is it because 21 metres is too far to cause heave no matter what the soil is?

 

 

Thanks again for all the replies.

[Jon Heuch]

This is a complex issue and not one that an arboricultural consultant should have much to say on.....unless they have experience of heave and know what procedures to follow.....typically with the guidance of a structural engineer.....and it's easier just to ask the SE to do it!

 

So what does it take to assess the risk? It requires an assessment of whether there is a persistent moisture deficit in the soil over the whole soil profile (to at least 4 metres depth) and that cannot be done by looking at a tree! It also requires some complex assumptions/calculations. Once done it requires an assessment of whether the structure can withstand the measure of soil expansion calculated.....another thing that an arboricultural consultant should not be doing....so a light structure (e.g. a wall) is much more likely to be affected than a heavier one (e.g. a house).

 

It is also useful to know the type of foundations that have been used; if the house is relatively recent and the tree was present when it was built we might hope that the foundations would have utilised anti-heave measures i.e. if heave was a possibility then it could have occurred when the foundations were installed .......so the house has a built in mechanism against soil expansion.

 

In conclusion, heave is not a common problem and most houses can put up with a bit of soil expansion; just make sure your house insurance covers heave and forget the risk.....there is not a lot you can do about it - after all the tree may die so what are you going to do then?

[Gary Prentice]

Excellent answer Jon. Can you elaborate on the anti-heave measures or suggest some further reading, please?

[sean]

I'd love to know why it is a 'waste of time' to pollard a willow? Unless of course you had already mentioned the long term management issue with regards the tree.