Eucalyptus blamed for Subsidence

[Lee Winger]

 

Eucalyptus is a huge and diverse genus with over 700 species, it is simply not true to try and argue that Eucs in general

 

The genus is big, granted, but the majority planted over here are eucalyptus gunnii

[Albedo]

No longer relevant in law, as even with a phased reduction the tree will extract the same amount of water as before the reduction, plus all living things die, you couldn't protect from heave, say if honey fungus struck and killed the tree, or it was hit by lightning.

 

When talking shrubs, I mean large laurels etc, even ivy and other climbers have caused subsidence, there was a case study where a row of trees were saved as it was proved beyond reasonable doubt, that it was shrubbery that caused the subsidence and not nearby trees

 

Thanks for elaborating on the shrub thing lee, that makes sense.

 

Tree biology next. I would have thought that a reduced tree with less foliage would remove less water by evapotranspiration.

 

And does your comment on tree law mean that we are immune from claims arising from the removal of trees on clay soils causing heave?

 

All with due respect, I know you know what your'e talking about:001_smile:

[Lee Winger]

Thanks for elaborating on the shrub thing lee, that makes sense.

 

Tree biology next. I would have thought that a reduced tree with less foliage would remove less water by evapotranspiration.

 

And does your comment on tree law mean that we are immune from claims arising from the removal of trees on clay soils causing heave?

 

All with due respect, I know you know what your'e talking about:001_smile:

 

I only put into practice what others far more experienced, experts in the field tell me. A reduced tree will use the same amount of water the next season,so this rules out supposedly all phased reductions and has for 10 years I know of. I think Mattheck did the research into this.

 

As for heave from soil expansion, this is a very very rare occurrence. The fact the tree was planted in the wrong place generally, and a problem with future subsidence is highly probable, would stand you in good stead if found in front of a judge, all I know is, most if not all consultants deal with the impending threat ie the tree rather than concerns about heave, to tell the truth I have wondered what might happen legally speaking if heave did occur, I think industry practice would save your ass TBH

[Albedo]

Thanks for the thoughtful response Lee, some stuff to ponder, we have a lot of clay soils around here and in the final analysis it is indeed my arse that most concerns me:001_smile:

[sean freeman]

The genus is big, granted, but the majority planted over here are eucalyptus gunnii

 

 

Interesting Cider gums are often not considered the best of the genus in many ways (two forms btw gunnii ~ a tree up to 25m tall... and archeri ~ generally considered to have poor straggly form almost mallee)

 

I wonder if its popularity over there is related to the use of its leaves in floriculture?

 

Cider gums are endemic to Tasmania on the plains and central highlands...the overall distribution is in the cold humid to wet climatic zone...sort of sounds like some parts of the UK?

 

It is frost tolerant and grows in altitudes where severe frosts and snow fall are numerous (good thing given your current weather!)

 

In its natural range mean annual rainfall is between 800 - 2800mm per year so each of you can decide weather that is relevant or not based on what you believe is driving and influencing evapotranspiration:sneaky2:.

[benedmonds]

Tree biology next. I would have thought that a reduced tree with less foliage would remove less water by evapotranspiration.

 

Check out the HORT link have to say about reductions and subsidence:

 

For practical soil moisture conservation, severe crown-reduction 70-90% of crown volume would have to be applied. Reduction of up to 50% crown volume is not consistently effective for decreasing soil drying.

 

http://www.myerscough.ac.uk/downloads/pdfs/Subjects/Arboriculture%20-%20NYTOG/NWTOG07/HortLink%20Project%20Final%20Report%20(2004).pdf

[Tony Croft aka hamadryad]

Interesting Cider gums are often not considered the best of the genus in many ways (two forms btw gunnii ~ a tree up to 25m tall... and archeri ~ generally considered to have poor straggly form almost mallee)

 

I wonder if its popularity over there is related to the use of its leaves in floriculture?

 

Cider gums are endemic to Tasmania on the plains and central highlands...the overall distribution is in the cold humid to wet climatic zone...sort of sounds like some parts of the UK?

 

It is frost tolerant and grows in altitudes where severe frosts and snow fall are numerous (good thing given your current weather!)

 

In its natural range mean annual rainfall is between 800 - 2800mm per year so each of you can decide weather that is relevant or not based on what you believe is driving and influencing evapotranspiration:sneaky2:.

 

Thats spot on sean, you know your onions that much is clear. i prefer the snow gum myself, a flipping stunner at kew

[Albedo]

Check out the HORT link have to say about reductions and subsidence:

 

For practical soil moisture conservation, severe crown-reduction 70-90% of crown volume would have to be applied. Reduction of up to 50% crown volume is not consistently effective for decreasing soil drying.

 

http://www.myerscough.ac.uk/downloads/pdfs/Subjects/Arboriculture%20-%20NYTOG/NWTOG07/HortLink%20Project%20Final%20Report%20(2004).pdf

 

That is a steamingly good link, what a fine bit of research. Its even influenced the new British Standard and made a lot of people including the AA sit up and take notice.

 

I haven't had time to fully study it but the bit you quoted does seem to be the important bit. If you reduce by less than this the leaf area is recovered after one or two growing seasons depending on species. It also backs up what Lee was saying.

 

I avoid mature trees on clay soils near buildings anyway, but will read this properly when I've got a bit more time.

 

Thanks for posting:thumbup1:

[Bundle 2]

I have always thought that the eucs shallow rooting nature within the U.K (so many are leaners) is due to their lack of need to throw down deep roots here......

 

 

I have noted the same thing.Typically the result of storm events, so higher than average winds but importantly, often associate this with very wet soils ( FC +) Shear failure of roots.....

Thanks Sean for provenance detail as I has suspected anatomical "adaptations" to climate and endaphic factors responsible....Not very likely!

 

Check out the HORT link have to say about reductions and subsidence:

 

 

Good link!

 

Tim

Edited December 1, 2010 by Bundle 2

[Tony Croft aka hamadryad]

This is turning into a great thread!