I find it fascinating how a shift of perspective can totally change the picture of something which is in itself deeply familiar.
Take monitoring for Asian Longhorn Beetle for instance… in this case your perspective shifts from the macro to the micro scale. Trees are large structures, but here you are looking for things the size of a corn of rice. And suddenly you notice aspects of a tree you had never noticed before, despite having climbed past them many times, such as small blemishes or bore holes.
Yesterday was a similar insight working in Brooklyn’s Green-Wood cemetery with Phil Kelley. The question here is what to do with an over-mature tree population. The cemetery is very interested in retaining these trees, many of which have historical or emotional significance and as such qualify as heritage trees. Yet at the same time, many of them are not in a good condition, populated by a plethora of fungi and a whole host of structural defects.
The shift in perspective here for me was that here is a case where the tree owner realises that their trees have problems but wants to keep them regardless. Oftentimes this will be the point where a tree is removed. I am very glad that in this case the owner is taking a different approach. We are looking at retrenching the trees, inducing their old-age shape with a reduced crown mass, reduced lever arms and the overall weight of the structure. As this is not an everyday set of parameters, you are forced to really think out of the box, considering what you know and what you do not, what you can back up with your risk assessment and an approach based upon due diligence.
What yesterday showed clearly is that the tree you are working with needs a certain level of vitality to be able to handle the intervention, if this is not the case, removing crown mass and causing wounds will likely be detrimental and not lead to the desired effect. The first tree we worked on however was bushing up nicely from the inside, offering plenty of regrowth to prune the canopy back to, the end effect being a much more compact tree than the large structure with lots of dead limbs we started with.
Neville Faye talks about how trees grow for three hundred years, live for three hundred years – and finally die for three hundred years. It is very satisfactory to be able to be part of such a process and it will be highly interesting to see how the trees here in Green-Wood respond to the pruning being done this week.