Last year I wrote a blog post about very large Sequoiadendron we did some work on which had been struck by lighting, after the arborist company which did the initial assessmen after the strike had condemned it straight-out.
Last week we went back to do a control on it and to see how it has developed since the work we did back in January 2016. We installed 15 threaded bars to stabilise the crack caused by the lightning, removed the top off the tree and reduced weight on the uppermost branches. The decision to take this course of action was based upon the fact that after all Sequoiadendrons are nothing other than giant lighting conductors, often loosing bits to this kind of incident and over the ages have evolved strategies to cope with them. Given that the tree seemed very vigorous and that apart from the crack the overall stability of the tree was not affected, we assumed that after stabilising the crack and reduction of weight off the top of the tree regrowth would close up the exposed top of the tree.
So we went round to the site last Friday to do a inspection.
Not often you max out your base anchor like this… at least not in this part of the world.
Once we got to the top I was very pleased to see good regrowth on the limbs and stem. This is probably also due to a robust watering regime we defined, as well as dumping a load of compost round the base and treating it with compost tea since the work we did last year.
Well, that and the fact that we were dealing with a healthy, vigorous tree from the get go.
Certainly one of the more spectacular views of town and the Rhine from up there… talk about the perks of the job.
What was very interesting was seeing how the tree had reacted to the threaded bars we had drilled and inserted to stablilise the crack. The tree has formed reaction wood around every bar, covering the washers almost up to the bolt in some cases. I expect that when we go to do the follow-up inspection next year, that these should be partially covered over.
I was talking a couple of weeks back to the person who did the initial assessment of the tree and effectively condemned it, saying it had to be taken down immediately. Admittedly, the damage is substantial with a scary crack. But this shows how there are other ways to mitigate risk than always simply defaulting to removing a tree with structural problems. This person was very interested in how we bolted the tree, saying that he had no experience with these techniques, and therefore recommended the removal. This I found surprising.
Actually, after having written this yesterday, rereading it this morning I realised that maybe I was being a bit uncharitable. In the end, there is always a fairly large degree of subjectivity involved when assessing this kind of situation. Maybe it would therefore be fairer to simply say that what we perceived and the conclusions we drew from it obviously differed.
Because, to be honest, nor did I.
But I decided to find out more about it: I simply spoke to arborists who were active back in the days of tree surgery, scored the gear to do the work off my friend, Alan, who found it buried down in level seven of his cellar, read up about bolting techniques in P.H Bridgeman’s book Tree Surgery and also Sharon Lillly’s The Tree Worker’s Manual, followed up by a chat with Sharon. I suppose the point I am trying to make is I find it a narrow vision that the mere fact that the required techniques are a little outside of my comfort zone and experience is sufficient reason for me to not even consider them. After all, that means you are discarding the opportunity to improve you knowledge.
And also, in this case, the alternative route allowed us to preserve a beautiful, important tree.