oak branch failure

[haljam]

Hi there, Wonder if I could pick the brains of the forum on this one - thanks.

What do you reckon has caused this to fail?, and what is the best action to take on the stub?

It happened last Monday evening, no wind, or storms. Apparently multiple loud cracking sounds, (which the neighbour thought was the whole tree coming down), followed by really loud crack. The branch was left is suspended by thin strip of wood. Tree is TPO' d, but this was hanging over the new fence and next door's summer house, so I winched it off to make it safe. Looks like a 1.5m long split (hazzard beam crack?), but I was up there last year hanging off this branch and saw no signs of damage.

Client is worried that whole tree might be suspect, as this fell off without only a 5 second warning. Buds were just starting to burst into leaf and the rest of the crown looks pretty healthy to me.

I take it its best to take the stub off back to the trunk? Or would you just trim off the damaged end, as the only other substantial leaf growth off this branch is close to the split. TO is on holiday at the moment so not been in touch yet.

[KevN]

If there are no signs of damage on the remaining part of the limb I would just tidy the end by trimming it back to the grower.

[Perkins]

I wouldn't prune it back to the stem until you have spoken to the TO, because it isn't life threatening at this stage and would leave a large wound. Hard to estimate, but looks like greater than 1/3 of trunk diameter and therefore contrary to 3998. Prune it back to the sub-lateral.

The contrast in the picture isn't great, but it looks like there isn't much evidence of decay, it may have been compromised by high winds and twisting earlier in the year i.e. abiotic damage rather than biotic.

[treeseer]

Agree to remove shaggy bits back to lateral and leave it. not really sure about 1/3 rule re branch to stem, but i like the sounds of it--the smaller the wound the better! And avoid exposing heartwood.

 

In the pic there looks to be a previous pruning wound near one end of the break. ? And discolored wood at a bulge at the distal end of the break. 3 mechanical constraints, including the crook (sharp bend).

The whole tree seems to sprawl so it seems reasonable to propose reducing the heaviest limbs above, lightly, to prevent this history repeating itself. 15% off the end can increase stability by 50%.

 

This might also have the added benefit of increasing sunlight to that remaining lateral, sustaining the broken branch as well. + Removing the whole limb would also increase risk of failure of remaining limbs.

Edited April 28, 2014 by treeseer