RPA's for fat trees?

[Paul Barton]

Hi Ben. I can't offer a good authoritative text to quote to help your situation. Perhaps looking at the site specific soil conditions might help explain a deviation from the standard RPA calculation (or shape at least).

 

Root length and depth is (in my limited understanding) strongly associated with ground conditions, particularly the availability of water and air. In highly compacted urban areas it seems that roots may need to travel further at shallower levels to obtain the necessary moisture where oxygen is also present. In an unsurfaced free draining soil, roots are likely to be shorter and deeper as they have all they need to function within a shorter distance from the stem.

 

Other than that, perhaps it's best to stick with the standard BS calculated RPA as a rule, but for trees that really are worth retaining but could pose a conflict, get your spade out and have dig to see what is actually there.

[Gary Prentice]

 

 

In the end if a LA is being difficult, it runs the risk of losing a refusal at appeal. But at the appeal somene will have to persuade an Inspector with perhaps very little tree knowledge that a deviation from a British Standard is sound. I think the onus would be on you to make the case for disapplying the BS rather than the COuncil proving that it does apply.

 

I don't know the in and outs of appeals apart from the TPO/CA refusal perspective. If the fast track system is opted for, at least an arboricultural consultant has the final say.

[treeseer]

" the morphology and disposition of the roots,..."

If this translates into the form and location of the roots then jolly good. Use a trowel and probe to locate roots, and proceed to protect them. No need to protect dirt with no roots, or 100% of any tree's roots, just because of soy stains on shredded cellulose.

 

As with assessing interior wood decay, formulas might be useful, but direct physical evidence is the gold standard of data.

 

This seems to fit all sites, not just those that are influenced by past or

existing disturbance.

[MATTMOSS]

" the morphology and disposition of the roots,..."

If this translates into the form and location of the roots then jolly good. Use a trowel and probe to locate roots, and proceed to protect them. No need to protect dirt with no roots, or 100% of any tree's roots, just because of soy stains on shredded cellulose.

 

As with assessing interior wood decay, formulas might be useful, but direct physical evidence is the gold standard of data.

 

This seems to fit all sites, not just those that are influenced by past or

existing disturbance.

 

Seems like a logical answer.

[treeseer]

Seems like, but is it?

 

Does BS5837 advise improving soil around the protected roots, to boost their function?

 

A vital step, increasing resources.

[daltontrees]

Seems like, but is it?

 

Does BS5837 advise improving soil around the protected roots, to boost their function?

 

A vital step, increasing resources.

 

It says that if operations within the root protection area are proposed the arboriculturist should propose a series of mitigation measures to improve the soil environment that is used by the tree for growth.

 

So, not quite. The mitigation measures could go beyond the RPA. The mitigation isn't called for unless there is breach of the RPA.

[Paul Cleaver]

Use the BS as a guide. Use your experience and knowledge to reach the final conclusion. Dont make hasty decisions, give yourself time to absorb the situation, sleep on it.