The standard is a lengthy and technical document. If we attempt to follow it in practice it is going to mean some big changes in the way we do things and probably make our working lives more difficult.(Sorry, by we I am generalising I know).
The thing that is difficult to admit is that most of what we do to trees in the name of arboriculture does nothing to help the tree at all, in fact every pruning cut we make is an injury to the tree and the bigger the cut the more serious the implications to energy, vitality and physiological integrity of the tree as well as later mechanical integrity. We cut trees to suit our ourselves not our trees. Ok, sorry, I don't mean to sound patronising, most of us know this is the case and my own work generally ends up as tree raping to be honest. The point is that the new standard brings our management objectives and doing least damage to the tree closer together.
There is so much scientific knowledge and understanding of tree biology and physiology now and in the BS3998:2010 we have been given a manual of how to achieve what people want without unwittingly bringing a very premature end to the life of a tree.
There is no doubt that there are circumstances where the recommendations are impracticable and impossible to implement. Not all trees lend themselves to precise radial reductions, sometimes the outer edge of the canopy has formed and divided far out on branches and there are no suitable laterals to prune back to at the specified distance. Other trees will be so thin and fragile out at the specified distance that it will be dangerous for man and tree to get out there.
There will be many "management objectives" that cannot be met by adhering to the document. Providing value to the customer that want's more light by giving a tree a 12% radial reduction might be impossible.Perhaps it may result in more removals.
Educating the customer will be a challenge if we attempt to make such a change to the way tree work is done and perceived.
One of the key things about tightening up on specifying reductions accurately is ensuring that the tree is not robbed of so much photosynthetic material that it's reserves of carbohydrate are used up to replenish them. There is a huge difference in leaf area removed by a 12 and 30% radial reduction, perhaps as much as 30% down to 90%. The long term implications for the tree might not be obvious but trees rely on energy reserves for many functions .
The recommendations for total cross sectional area of pruning cuts not to exceed one third of total cross section of the stem at 1.5m is at first straight forward enough. When I considered the examples given in table 1, 7.2.4, page22, I struggled to believe the maths but it does all add up, now that I know how to work out the area of a circle.
It is all too easy to exceed these figures, especially when crown lifting. This is a good practical guide.
The recommendation for stages or phases in tree work reduce the stress and physiological dysfunction within the tree makes sense to me but I'm not sure it will to the customers. If they want what's best for the tree and we can communicate these recommendations to them, then it will work. However, it will mean an ongoing commitment from them, which will be good for business.
Giving greater consideration to the condition of the rooting environment makes total sense. Recommending mulching could add to revenue and be good for the tree but are there potential pit falls here? How much do we/I know about the correct and best way to mulch?
Damage to the roots and rhizosphere during tree work is something I never used to consider, but it should be given careful thought. Two days of trampling around under a tree and dropping missiles into the soil is bound to do some harm. What can we do about that whilst remaining competitive? Mulch to the drip line before starting work?
Anyway, I'm boring myself now.
It is the future, it is about educating ourselves and the client but it is going to take a long time to make it the general standard of tree work in my opinion. It is a really good document, even if it causes a few inconvenient difficulties in the conscience.