Oak Tree Treatment

[UrbanBK]

Hi I hope someone can give some advice. My Mum's neighbour has always been really helpful in looking after her garden and about 2 years ago he decided to pollard her Oak tree. He also treated with "tar oil" as there was apparently an insect infestation on the tree. Since this was done the tree hasn't really recovered, has been some green growth on the tree, but this appeared to die off in August.

The oak is nearly 50 years old so I’d like to try and do my best to try and save this if I can. Any suggestions on how to remove the oil off the tree?

I'm not sure if it makes any difference but the tree is on a slight incline.

The photo with the green shoot was taken in May, the later one was in August this year. Any advice would be greatly appreciated.

What time of year was it pollarded?

It’s not a thing of beauty any more, is it?

Oak trees support a greater number of species than any other tree, they’re immensely important for biodiversity. Too right there was an insect “infestation” on it.

Am I right in thinking that he has basically covered the trunk with tar, right up to the lowest branch? You can get chemical removers of tar, but I’d only use that as a last resort. Try vegetable oil to dissolve the tar, then wash off with washing up liquid and water.

Oh dear, that's dreadful. Poor tree.

Thankls for the reply. I think it was late Autumn approx 2 years ago

Thanks for the advise. Yes it's covered the trunk with what he described as "Tar Oil" up to the lowest branch. Will it be too cold to use vegetable oil at this time of year?

I had though of using a pressure washer on a low setting to wash it off after the vegetable oil, would this be too harsh?

Will it be too cold to use vegetable oil at this time of year? Perhaps easier once this cold snap is over. Will the tree have a shock if its tar overcoat is removed? - not a question I’ve ever had to think about before. I don’t even know whether it’s a good idea to remove, but personally I wouldn’t want that trunk in my garden even with a live tree on top.

I had though of using a pressure washer on a low setting to wash it off after the vegetable oil, would this be too harsh? I wouldn’t

Fruit trees used to be routinely sprayed with a tar oil wash in winter, but this was reapplied every year. So I wouldn’t expect it to be showing up as a clear black trunk 2 years later. It’s now been withdrawn because of carcinogenic properties.

What does it actually look like? a) a thick sticky black coating b)just dark as if you’d treated a fence post with Cuprinol or similar If b) I wouldn't try to remove it.

Oaks shouldn't really be pollarded at all, but if the work has to be done, then the right time of year is midwinter/early spring when the tree is completely dormant.

The one and only reason to be concerned about pests on an oak tree would be Oak Processionary Moth. They are jolly nasty things and harmful to human health. Anything else would be a natural part of the ecosystem. But they are only really active from April onwards and there shouldn't have been anything to see on a tree in the autumn to warrant this kind of drastic action.

With this poor tree, I think you are going to have to sit it out and wait till next year. Tar oil and substitutes are only supposed to be used to seal the cut ends of branches to protect against pathogens and so on. Painting the entire tree with it was overkill to say the least.

I do wish people who don't know what they are doing would leave trees alone.

Oh my goodness, all of that tar all over the trunk, horrendous!! What was he thinking!! Trees have lenticels on their trunks which are basically pores for gaseous exchange of co2, oxygen and water - he has probably sealed them all up. No wonder the tree isn't thriving, it can hardly 'breathe'. I mean to get it off would probably take a solvent but that in itself is poison and I wouldn't recommend using that on a living thing. I don't honestly know what to suggest, this may not be something that can be fixed. Poor tree. My main recommendation would to never let that neighbour near your mum's garden again. I don't know what benefit there would be in pollarding an oak, unless it had loose dangerous branches. Actually I would contact an organisation that specialises in trees and ask for some advice - contact the RHS, they have advisors, or the Woodland Trust, they might have a solution.