Who supplies root deflectors?

[Bundle 2]

I accept that a major cause for concern with regards the "planter" style , bottomless bucket would seem to be girdling....This is a major concern for any self respecting nursery grower aswell if Barchams assessment of the situation is anything to go by.....

I would still maintain that a suspended structure, what you landscape architects and such call "no dig " ( I hold an NCH -Landscape aswell doncha know!!) actually delivers optimum performance for both aspects of the development.....trees and structure in relative harmony.....

I suppose what Im really saying is that the deflectors are useful cos I can see how it works with kurbs maybe-something was said in the above links re: one/two side root obstacles....What is less clear is the overall effect of needing to use a an enclosed barrier; It strikes me that roots will return to the surface where they gain oxygen necessary for life anyway...all you do is make life a convoluted process in the interim? As establishment is quite an issue with losses post planting ( certainly larger, commercial/public/industrial projects ) running at 25-50% typically...I can only assume that there is an underlying method in the madness cos I would prefer to use a no dig in the immediate vicinity. It would surely only need to be very modest in its extent in order to mitigate the pressures on newly built structures IF you accept that roots return to the surface anyway as soon as they are outside the barrier and able to do so??

 

" PS I liked your brain-eating avatar, where did it come from? "

Ah, ripped off the web somewhere along the way..cheers!

 

Edit-Just cos I wa reading around this subject today and it fit nicely into the seminar at Barchams on weds....a link relating to girdling and such...

 

http://www.extension.umn.edu/distribution/naturalresources/DD7501.html

Edited July 16, 2009 by Bundle 2

[Bundle 2]

Sorry if this is gettin' off topic folks......

root_collar_disorders.pdf

[Giles Hill]

With no-dig vs structural soils, it may depend on who's research you read.

 

I think it would depend a lot on the site - in some circumstances a structural soil is likely to provide a better growing medium than what's there to begin with.

 

I've not had the oppurtunity to specify ground protection for areas to be planted yet. It can make a job of getting the final levels to match up, particularly where space is restricted, as is the case on most development sites. I like the idea of it though!

[Bundle 2]

Mmm...structural soils have a fairly limited lifespan.

Levels are likely to have a bearing on suitability of "no dig"- presuming there are trees/plants present at the time of development.

" likely to provide a better growing medium than what's there to begin with....... " Ph levels are often along way from normal post development... Planners and designers need to specify in order to procure success. It is in the interests of their clients in the long run.

[Giles Hill]

Why do you say structural soils they have a limited life-span?

 

Regarding levels for new planting, it's more than likely that the finished ground levels will be different to the existing, therefore to get the soft landscape areas to match, it will often be required to reduce them by a foot or so and therefore you'll remove most of the topsoil.

 

Regarding the comparison of structural soils to existing ground, I was meaning the existing ground on development sites is variable and depends on things like the former land use and recent activities that have taken place.

[Bundle 2]

"Regarding the comparison of structural soils to existing ground, I was meaning the existing ground on development sites is variable and depends on things like the former land use and recent activities that have taken place."

 

Sure....isnt that why they get used.The compressive strength is good and results in no further "compaction" A very good idea in many ways.Especially as you point out, change of use might point to towards a deficit in adequate topsoil/growing medium.Drainage issues and stability would seem to be well addressed.

 

"Regarding levels for new planting, it's more than likely that the finished ground levels will be different to the existing, therefore to get the soft landscape areas to match, it will often be required to reduce them by a foot or so and therefore you'll remove most of the topsoil...."

 

Doesnt seem like a terribly practical approach. If for no other reason than it requires grading and removal of spoil. I probably dont appreciate the constraints. It could be too high....equally, the other way round though right?

I say "limited lifespan" because there is not the same dynamic as a regualar soil. Only a relatively small percent is a growing medium ( 20-25%-I dont know...something like that )