Butt pollarding Oak tree

Ok chaps, here is a challenge

Four years ago i was asked to reduce the crown of the Oak in the photos below, which I did.

Last month I was asked to re-prune the crown to control the density and spread, for safety reasons. This year I found a ganoderma bracket under the tree but I dont know which variety it is. It measures 22cm long and 16cm wide.

The tree is big (75ft tall, DBH approx 65inches) and slightly one sided, very close to two houses and on a reasonable slope.

Most notably the tree appears to have good vigour, however, the butt is rotting out. The buttresses are becoming pillars and the wood inside is pretty soft.

Wall thickness on the buttresses, as shown in the photos all taken today, appears to be ok but not brilliant.

My questions are:

1. Which Gano is it?

2. What would you do?

The owner is very safety minded, loves the tree and it is a real prominent feature on the landscape.

Over to you..........

Thats going to have to come down in the next few years pollard then fell in 2 years ? get paid 3 times for doing the tree.

Reduce by 20% each year to pollard. Would give tree slightly better chance than having all branches hacked off in one.

Most notably the tree appears to have good vigour, however, the butt is rotting out. The buttresses are becoming pillars and the wood inside is pretty soft.

Wall thickness on the buttresses, as shown in the photos all taken today, appears to be ok but not brilliant.

My questions are:

1. Which Gano is it?

2. What would you do?

The owner is very safety minded, loves the tree and it is a real prominent feature on the landscape.

1. On Quercus, most probably G. australe, the most "aggressive" heartwood rotter compared to G. lipsiense, but 100 % sure : microscope (spores).

2. Hard to say without self-inspection and diagnosis and/or by a photo alone, but as long as the oak stabilizes itself by developing buttresses shaped as pillars or columns of wood, even with the cavity, the tree will stay save for some to even several years.

Ranger you mention reduce by 20% on a regular basis until a pollard/safe height is reached. Well this will be costly to the client, why not picus test to ascertain the extent of the decay then go from there if the client is willing to pay for this.

As Fungus has said the tree could live with this for many several if not decades possibly, Gano is not immediatly dangerous, but investigation is needed to ascertainb how far the decay has progressed and the trees vigour.

Also best to leave perenial fruiting bodies on imo

Marc, you question Rangers pollarding view because of cost but the suggest expensive Picus testing!?

Also, Fungus said years not decades.

I couldn't get a half decent photo of the bracket without removing it unfortunately.

Where are Hamadryad and Monkey D when you need them?

One other point to note is that there has been no adaptive/reaction (swelling) growth over the buttresses. This is noticeable in photo 2 and the appearance is the same from every angle.

This concerns me due the 'rotting out' characteristics.

Any further thoughts on this?

I couldn't get a half decent photo of the bracket without removing it unfortunately.

That's unfortunate, as because of this, it's not possible to adequately monitor the yearly development of new tube layers on the brackets and diagnose the "body language", i.e. panic reproduction of it as a symptom or predictor of the danger of the fall of the tree, as building "reaction" layers of the bracket now can also be a reaction of the mycelium to the damage done to the bracket.

That's unfortunate, as because of this, it's not possible to adequately monitor the yearly development of new tube layers on the brackets and diagnose the "body language", i.e. panic reproduction of it as a symptom or predictor of the danger of the fall of the tree, as building "reaction" layers of the bracket now can also be a reaction of the mycelium to the damage done to the bracket.

Hi fungus, so if a bracket is panic reproducing, what difference might you expect to see in the tube layers? Thank

Hi fungus, so if a bracket is panic reproducing, what difference might you expect to see in the tube layers?

Because of the lack of energy delivered from the diminishing decomposition of cellulose by the mycelium, needed for forming new layers, the tube layers retract or withdraw while covering the earlier formed pores and layers, as you can see in the photo of an old Phellinus igniarius on an almost completely heartwood white rotted willow.