Removal of tree close to footpath, carpark and property

[Dbarnard]

Hi I was looking to remove a 30 year old hawthorn from the back of my garden. The tree is around 10m high and 6m wide. I've attached pictures. The tree is next to a tarmac foot path and around 1m from that is a hedge with stone risers and 1m from that is a blocked paved carpark. There is a property 5m to the left of it.

 

Ive been reading online about ground heave and it has me very worried. From the facts I've gathered.

 

The property was built in 1979. So the tree was planted after the property was built.

 

I'm trying to work out if the soil is clay because I've heard that can be bad as it can swell when the tree I removed. Do you know how I can test this? Dug a whole by the tree this morning. Its black and slightly sticky. Worried about it because i know for certain that around 5m from the tree back towards my house theres a patch of clay.

 

I'm trying to gauge what steps I need to do to remove the tree. I have read online a gradual reduction of 1/3 a year can work? And when the tree is eventually a stump it can be grinded out. I've read that this means the soil can recover per year.

 

Behind the tree it's pure tarmac I.e theres no soil. But I'm paranoid what's beneath the tarmac. One picture I've attached is where the tarmac on the boarder has slightly raised. It isn't huge but it has me worried the roots have propagated out further.

 

If and when the stump is removed I guess I need to contact the council to repair the tarmac.

 

Just looking for advice really. I've contacted an alborist to see what they have to say but just trying to gather information.

 

Edit: had another look at the soil I think it is loam/clay you can feel grit in some bits but you get the odd bit that is silky smooth. I've had a look on a soil map of the uk and that matches with that. The soil map says theres a slight impedance to drainage. Hoping this is only really an issue for pure clay soil?

Edited December 23, 2019 by Dbarnard
Checked soil type

[peatff]

I took one out in our garden (it was blocking light from wife's veg patch), started at the bottom and worked my way up the stem cutting branches off as I went. I don't envy you as they are hard wood and evil thorns but there was no effect on the ground after I took it down and I drilled the stump and killed it with weedkiller. I wouldn't get too hung up on ground heave from something like that just get it down if it is in the wrong place for what it is although the birds do like them.

[Dbarnard]

Thanks petif for your quick reply. Getting rid of it because I find the tree is too close to the boarder and dont like how it sags the fence. It also overhangs the car pack too much  it looks amazing in summer but I've had it two winters now and the leaf fall and berries is too much to handle so want to simplify things. I plan on planting a Himalayan birch tree in its place but further from the boarder. They are more maintainable from what I have read and stay around 6m high which sounds ideal.

 

Believe it maybe a snow queen birch actually

Edited December 23, 2019 by Dbarnard
Clarified new tree type

[JonnyRFT]

On 23/12/2019 at 10:07, Dbarnard said:

Hi I was looking to remove a 30 year old hawthorn from the back of my garden. The tree is around 10m high and 6m wide. I've attached pictures. The tree is next to a tarmac foot path and around 1m from that is a hedge with stone risers and 1m from that is a blocked paved carpark. There is a property 5m to the left of it.

 

Ive been reading online about ground heave and it has me very worried. From the facts I've gathered.

 

The property was built in 1979. So the tree was planted after the property was built.

 

I'm trying to work out if the soil is clay because I've heard that can be bad as it can swell when the tree I removed. Do you know how I can test this? Dug a whole by the tree this morning. Its black and slightly sticky. Worried about it because i know for certain that around 5m from the tree back towards my house theres a patch of clay.

 

I'm trying to gauge what steps I need to do to remove the tree. I have read online a gradual reduction of 1/3 a year can work? And when the tree is eventually a stump it can be grinded out. I've read that this means the soil can recover per year.

 

Behind the tree it's pure tarmac I.e theres no soil. But I'm paranoid what's beneath the tarmac. One picture I've attached is where the tarmac on the boarder has slightly raised. It isn't huge but it has me worried the roots have propagated out further.

 

If and when the stump is removed I guess I need to contact the council to repair the tarmac.

 

Just looking for advice really. I've contacted an alborist to see what they have to say but just trying to gather information.

 

Edit: had another look at the soil I think it is loam/clay you can feel grit in some bits but you get the odd bit that is silky smooth. I've had a look on a soil map of the uk and that matches with that. The soil map says theres a slight impedance to drainage. Hoping this is only really an issue for pure clay soil?

I wouldn’t be so concerned about the soil. Its demand on water will be relatively small compared larger species of tree that can cause issues with clay soil. 
 

The tarmac damage from the roots seems pretty minor too. It’s not even lifted it enough to crack thus later creating a trip hazard.

My suggestion...

 

Have the tree removed and perhaps request the stump to be treated.

Eco Plugs containing glyphosate can be an efficient and effective method for the tree to absorb the chemical preventing regrowth.
Be sure they are inserted as close to the outer, softer and sappy layer to allow the transport of chemical back down to the roots.

 

No further works should be required.

 

Kind Regards,

[Chris at eden]

17 hours ago, JonnyRFT said:

I wouldn’t be so concerned about the soil. Its demand on water will be relatively small compared larger species of tree that can cause issues with clay soil. 
 

 

Hawthorn is a high water demand tree with a zone of influence of 12.5m so this comment doesn't really stack up.   No offence intended, just pointing out the facts. 

[Gary Prentice]

23 minutes ago, Chris at eden said:

Hawthorn is a high water demand tree with a zone of influence of 12.5m so this comment doesn't really stack up.   No offence intended, just pointing out the facts. 

To be fair Chris I think that the Water Demand tables came about more due to the requirements of the insurance industry than being based on  scientific research and evidence, in that trees frequently associated with subsidence were rated in the higher categories.

 

Hawthorn, being a relatively small species are frequently planted near to properties and hence have a higher association with subsidence than maybe warranted by the amount of water they use.  I'm sure that Gile Biddle is pretty scathing about how they were produced.

 

 

But I'd agree, in the wrong soils and with shallow foundations that tree would have the potential to create subsidence (most trees of that size would)

 

Getting back to the question in hand. 

 

Is the property showing any symptoms of subsidence? Cracks that change in width seasonably, particularly around openings such as doors and windows. Generally unless you have subsidence problems heave is of little concern. 

 

Removing a tree of a period of time is no longer recognised as a means of preventing heave. It'll just cost the owner more. If the tree has caused a soil moisture deficit and a volumetric change (shrinkage = subsidence) the eventual return to equilibrium (expansion = heave) will be the same. reducing the tree over a number of years only prolongs the time for the soil to reach its full wet volume.

 

EDIT;

Not all clay soils are involved in heave/subsidence. Only certain clays, made of particular materials, have a high shrink/swell potential, so more information than just clay content is needed before the probability of soil expansion can be considered.

Edited December 30, 2019 by Gary Prentice

[Chris at eden]

On ‎23‎/‎12‎/‎2019 at 10:07, Dbarnard said:

Hi I was looking to remove a 30 year old hawthorn from the back of my garden.

 

How do you know its 30 years old? 

On ‎23‎/‎12‎/‎2019 at 10:07, Dbarnard said:

The tree is around 10m high and 6m wide. I've attached pictures. The tree is next to a tarmac foot path and around 1m from that is a hedge with stone risers and 1m from that is a blocked paved carpark. There is a property 5m to the left of it.

 

Ive been reading online about ground heave and it has me very worried. From the facts I've gathered.

Subsidence is a lot more common than heave but under the right conditions there could be a risk. 

On ‎23‎/‎12‎/‎2019 at 10:07, Dbarnard said:

 

The property was built in 1979. So the tree was planted after the property was built.

Assuming that the tree is 10 years younger than the house then the risk of heave should be low.  I wouldn't assume anything from the photo though, if you have concerns get it surveyed properly.    

On ‎23‎/‎12‎/‎2019 at 10:07, Dbarnard said:

 

I'm trying to work out if the soil is clay because I've heard that can be bad as it can swell when the tree I removed. Do you know how I can test this? Dug a whole by the tree this morning. Its black and slightly sticky. Worried about it because i know for certain that around 5m from the tree back towards my house theres a patch of clay.

Not all clays are shrinkable.  To be shrinkable, at least 35% of the soils make up (just the solid parts) must be fine clay.  You can get this tested at a lab using the Atterberg Limit Test, its not cheap though.  You could also look at the online BGS viewer to get an idea.  Its not 100% accurate but I use it for mortgage reports as long as there is no pre-existing damage.    

On ‎23‎/‎12‎/‎2019 at 10:07, Dbarnard said:

 

I'm trying to gauge what steps I need to do to remove the tree. I have read online a gradual reduction of 1/3 a year can work? And when the tree is eventually a stump it can be grinded out. I've read that this means the soil can recover per year.

I know this is out there in a BRE practice note but it doesn't stack up for me.  If you have the tree removed in one go or in stages it will recover to the same level if there is a persistent moisture deficient.  Other opinions may differ.       

On ‎23‎/‎12‎/‎2019 at 10:07, Dbarnard said:

 

Behind the tree it's pure tarmac I.e theres no soil. But I'm paranoid what's beneath the tarmac. One picture I've attached is where the tarmac on the boarder has slightly raised. It isn't huge but it has me worried the roots have propagated out further.

There will be soil and roots under the tarmac most likely. 

On ‎23‎/‎12‎/‎2019 at 10:07, Dbarnard said:

 

If and when the stump is removed I guess I need to contact the council to repair the tarmac.

It minor damage, I doubt the council will see that as a priority. 

On ‎23‎/‎12‎/‎2019 at 10:07, Dbarnard said:

 

Just looking for advice really. I've contacted an alborist to see what they have to say but just trying to gather information.

No one can advise you with the info provided.  You will need to get it looked at properly by a tree consultant if you want anything worthwhile.   

On ‎23‎/‎12‎/‎2019 at 10:07, Dbarnard said:

 

Edit: had another look at the soil I think it is loam/clay you can feel grit in some bits but you get the odd bit that is silky smooth. I've had a look on a soil map of the uk and that matches with that. The soil map says theres a slight impedance to drainage.

No comment - it's second hand info. 

On ‎23‎/‎12‎/‎2019 at 10:07, Dbarnard said:

Hoping this is only really an issue for pure clay soil?

Its not.  I've seen subsidence on Mercia Mudstone and Pennine Coal Measures. 

 

Again, if you have concerns then get it looked at properly.   

On ‎23‎/‎12‎/‎2019 at 10:07, Dbarnard said:

 

[Chris at eden]

6 minutes ago, Gary Prentice said:

To be fair Chris I think that the Water Demand tables came about more due to the requirements of the insurance industry than being based on  scientific research and evidence, in that trees frequently associated with subsidence were rated in the higher categories.

 

It doesn't actually relate to water uptake.  It's used to calculate the distance at which trees tend to cause damage based on observation.  Water uptake on its own isn't sufficient to cause an issue as you know.  You have to tie it in with the other observations made on site, again as you know. 

 

My point was that alluding to the fact it wont take up enough water to be an issue is wrong in this situation.  The tree is 5m from the building and has a ZOI of 12.5m.  In the right conditions that could be an issue. 

   

[Gary Prentice]

12 minutes ago, Chris at eden said:

It doesn't actually relate to water uptake.  It's used to calculate the distance at which trees tend to cause damage based on observation.  Water uptake on its own isn't sufficient to cause an issue as you know.  You have to tie it in with the other observations made on site, again as you know. 

 

My point was that alluding to the fact it wont take up enough water to be an issue is wrong in this situation.  The tree is 5m from the building and has a ZOI of 12.5m.  In the right conditions that could be an issue. 

   

Just trying to keep you on your Toes Chris! And I did concur with your ZOI/soil/foundation comment

[Chris at eden]

1 minute ago, Gary Prentice said:

Just trying to keep you on your Toes Chris! And I did concur with your ZOI/soil/foundation comment

 

Cheers mate.  Hope you are well. 

[JonnyRFT]

2 hours ago, Chris at eden said:

Hawthorn is a high water demand tree with a zone of influence of 12.5m so this comment doesn't really stack up.   No offence intended, just pointing out the facts. 

No offence taken. I’m often wrong and try to learn from mistakes but my original answer stemmed from the trees size compared to its location. Judging from the picture I would say there’s 9m to the closest property and the impact of the removal of this tree would be tiny. I would also hazard a guess that the tarmac is durable enough at this point to accommodate any further movement in the future after the stump is treated. There’s also a neighbouring tree (maybe Ash?) that may regulate moisture content of the soil over time.

 

But, I was unaware of the 12.5m zone of influence. Could this be the case for the tree in question considering it relatively small size?