Visual Tree Assessment Oak with Large split.

[Mazzoo]

Hi, I'm doing visual hazard evaluations on my level 4 course.   One of the trees is this mature Quercus Robur near playing fields which has a large split on the south side and a crack that has developed in the main fork of the tree (circled in the second photo). There are a couple of small hanging branches in the canopy coming from the split stem side but the leaf size, new shoots and foliage all look pretty normal.  From the split part of the trunk to just above the roots seems hollow and has a small amount of decay fungus (possibly Stereum rugosum?) and small insect holes. There looks to be old pruning further up the tree from the split, I'm guessing the severe split was caused by a large pruning wound? The roots look OK and no sign of decay there.  I'm thinking in terms of risk it's moderate to high as in my (quite novice) opinion the crack is huge and that stem is leaning quite a bit, it's not a constant use area but people do walk under it. I'm thinking the course of action would be to monitor more than annually or maybe remove the stem that is splitting to stop the strain on the main fork?

I'm looking for some other opinions on what I may have overlooked if anyone would care to add any.

[monkeybusiness]

Fence it off/prevent people from walking under it with informative signage explaining the management decisions and leave to nature would be my thoughts.

[Mazzoo]

1 hour ago, monkeybusiness said:

Fence it off/prevent people from walking under it with informative signage explaining the management decisions and leave to nature would be my thoughts.

Thanks for that. 

[Khriss]

Also remmember that is feeding the tree with that portion of the canopy, can see why they chose this, good conundrum. K

[Mr. Squirrel]

I guess you need to ask yourself the question ‘does it require management’ first. If the answer is yes then monitoring it isn’t really

management, but just delaying any decision making until it falls apart in some way and hopefully nobody gets hurt.

The split appears to be present on both sides of the union ie. also in vital and intact wood, so I’d presume is not caused by the decay associated with the major pruning wound. It also appears to be perhaps a few years old, so the tree might be coping with this itself. 
Removing that stem would create an even bigger pruning wound and make the problem even worse.  So definitely not that. 

[carlos]

reducing the end weight of the stem with the split in it would surely help it a bit.

[Patrick goulding]

I think some times it’s down to certain factors in my opinion. if it’s on a kids playing field I would say its a high risk and some type of work should be carried out to make it safe. But On the next breath if it was in the middle of a farmers field that tree could stay like that for hundreds of years. But there is a but will it you can’t really say so there still is a possibility so when it comes to joe public it can’t be chanced that’s my take on it. 👍 

[Patrick goulding]

The other factor I think is regards to how long do you leave something to decrease and then the poor lady or gent is in the situation of having to carry out the work. This tree would be easy enough to carry out the works. But some times people leave things not thinking of how are we going to carry out the work and what poor tree surgeon/ arb has got to go up it lot of factors. 👍 

[Mazzoo]

1 hour ago, Patrick goulding said:

I think some times it’s down to certain factors in my opinion. if it’s on a kids playing field I would say its a high risk and some type of work should be carried out to make it safe. But On the next breath if it was in the middle of a farmers field that tree could stay like that for hundreds of years. But there is a but will it you can’t really say so there still is a possibility so when it comes to joe public it can’t be chanced that’s my take on it. 👍 

Yes it is on a playing field but the part with the split is not directly over the pitch. Dog walkers do go underneath though, so that's why I thought it would be medium risk at least. 

[Mazzoo]

13 hours ago, Mr. Squirrel said:

I guess you need to ask yourself the question ‘does it require management’ first. If the answer is yes then monitoring it isn’t really

management, but just delaying any decision making until it falls apart in some way and hopefully nobody gets hurt.

The split appears to be present on both sides of the union ie. also in vital and intact wood, so I’d presume is not caused by the decay associated with the major pruning wound. It also appears to be perhaps a few years old, so the tree might be coping with this itself. 
Removing that stem would create an even bigger pruning wound and make the problem even worse.  So definitely not that. 

Thanks for your input. and everyone else's 👍    It does seems a bit of a conundrum to me if it needs some kind of management but not drastic pruning. Would removing weight further up help? I have to say I like the fencing off idea and leaving it, as it's one of my favourite trees where I go walking!

Edited May 23, 2021 by Mazzoo