A good aim in life, in my books at any rate, is to strive to constantly improve, to get better at what you are doing and not to repeat the same old mistakes.
In order to do so, you need to have the means to evaluate feedback, to recognize strengths and weaknesses – only then are you able to define areas in which you can get better. I suppose in the broadest sense of the meaning this is a form of quality control, a rolling evaluation of the work you are performing.
Take for example crane fellings: I do not understand how people can do these without documenting lifts, estimating loads and recording the actual weight. We have been doing this for a fair number of years now and it has helped me a lot in becoming more accurate when it comes to estimating loads – this does not mean that I do not sometimes underestimate a load, I do, but rather that when this is the case that I realize that I have done so.
Below are two shots of the lift documentation of an Ash tree we removed recently. We ended up having to do it in two goes separated by a few months, this was due to a colony of protected crows that had young in the nests at the time it was decided to remove the tree. As it was deemed to be structurally unsafe and right over a tennis court, the decision was taken to remove it in two steps. The crane we used on both occasions was a Liebherr MK110. We were maxing out its reach, with a load capacity of around 2t at the outmost point. During the briefing with the crane operator we decided to aim for one ton picks.
I felt this was an appropriate safety margin, especially in view of the fact that the weight of Ash can be quite tricky to estimate, due to its large vessels that introduce a high degree of variability in weight, depending on the amount of water that is being pumped through the system at that point in time.
Used in a responsible and competent manner, cranes are a great tool. At the same time, the other side of that coin is that if you get it wrong, bad things can happen. And bad things involving big machinery tipping over really are quite bad. Badbad. Doubleplusbad – potentially.
Attaching loads correctly so that the mass is held in position during the lift, correct work positioning, correct cutting techniques, clear communication between the climber, the team on site and the crane operator – and last but not least, documenting the lifts are all indispensable tools to ensure we are managing risks to the highest degree possible when big machinery meets arborist techniques.