The Resilience of Arboriculture

Tree Surveys - BS5837

There is a systemic, widespread fixation with providing baseline survey information solely on the measuring and categorisation of trees as outlined in BS5837. Worryingly this is more and more frequently done without adequate understanding and by arborists of limited experience. The profession is on a race to the bottom.

The average tree survey I come across is very rarely in accordance with BS5837. There are a number of common failings from incorrect data gathering to inappropriate allocation of quality category. It’s not about measuring trees as quickly as possible and applying generic rules of thumb to report key issues. For example…. here’s a quick discussion about one key concept that is consistently misunderstood.

Root Protection Area [RPA]

“RPA: the minimum area around a tree deemed to contain sufficient roots and rooting volume to maintain the tree’s viability…”

By definition this means that the RPA needs to provide a tree with enough soil to live, grow and develop. Logically, a minimum RPA cannot achieve this as it typically represents less than half of the actual rooting area - and working to a minimum RPA can only inhibit the future growth potential of retained trees.

Anchoring to the minimum RPA impacts mature trees the most. Young, healthy trees showing good vigour will no doubt recover from significant root loss - stressed or older trees are much more vulnerable. And in any case, to have any real understanding of where the RPA should be requires some knowledge of the particular soil on site. Please… DIG A HOLE.

There is a need to address the shortcomings of consulting arbs and raise professional standards. Inappropriate RPA information is but one argument from ignorance pervading its merry way through the planning system. The role of the arboriculturist is a challenging one - it takes knowledge, skills and experience. The current framework is failing and currently there is a lack of training, support and mentoring. In part this can be addressed with now ready-to-launch new training…

Arboricultural Impact Assessment [AIA] System & Training

More AIA system details to be released in the near future….

Plant BIG trees

If we really want big trees in our built environment it’s time to start looking for creative new ideas. I can’t help but notice the opportunities with Roundabouts!

I’ve been playing around with a few tree-planting ideas...and I think a campaign is called for. Trees are hot property what with climate change and current trends for canopy cover. And although policy is slowly changing for the benefit of trees - we need to be careful that it isn’t just lip service when it comes to new planting.

Roundabout - the perfect planting space?

Judgment Parker v The National Trust [2021]

The High Court dismissed this claim against the National Trust (the Trust) finding that it had properly discharged its duty under the Occupiers' Liability Act 1957 in respect of inspecting trees on its land and ensuring visitors were reasonably safe.  

The Trust had a properly implemented policy of tree safety management and the claimant visitor's injuries, caused by a falling tree branch, were the result of a tragic accident and not the Trust's negligence.  

The court was careful not to impose a standard of care that was inappropriately high.  The duty must be assessed in the context of the extremely low risk that trees pose and recognising there is no such thing as an entirely safe tree.  The court stressed the need for a risk-based approach to tree safety management through inspection.

Judgment Parker v The National Trust [2021]

Dig A Hole!

Not going underground - the root of the problem

Trees haven’t read the guidance about where they should grow roots. The science tells us that roots are typically shallow and can spread radially much further than tree height. But root growth is opportunistic, developing in response to specific site factors and ground conditions.

Two similar aged beech trees with root growth adapted to site ground conditions.

The same tree will root differently depending on its particular environment. And forget about applying rules-of-thumb to urban trees. Few arboriculturists fully consider the below-ground landscape when assessing trees in relation to development. Favouring a much more simplistic baseline - based on minimum soil volume requirements. How soil ‘volume’ can be evaluated by measuring a tree stem and plotting a radial ‘area’ defies logic.

Dig a Hole!

I try and dig a hole or two whenever I’m surveying - I’ve never been disappointed, or felt less informed about the soil and ground conditions.

Trees, Planning & Development - BS5837

Effective Arboricultural Impact Assessment (AIA)

Over the last 5 years I’ve been researching, developing and testing a new system of AIA. I have previously presented and published on the topic and (having now finished a large research project) I’ve identified some of our collective shortcomings, and developed a system to help iron out some the issues identified.

Ignorance, the root and stem of all evil can be accessed here… AIA.Winter.2018

I’ve now written a follow-up article for the next Arboricultural Association ARB Magazine. The article is about trees, planning & development. And our effectiveness as professionals. It outlines part of a new structured AIA assessment methodology and decision-making framework for evaluating the impacts (and opportunities) of developing near trees.

The Roots of Arboricultural Impact Assessment can be accessed here… AIA.Summer.2021