Big oak fell - help analyzing why!

[Cilla]

Welcome to give your expertize and clever thoughts on why this oak fell some nights ago! Short desciption and photos here:

 

Vällingbyeken som föll

[Paul Jenks]

Well it looks like the pressures of the adjacent development have probably done for this tree over a number of years. Ground level changes, including probably structural root severance.

There is a large industrial looking unit above the tree and its construction and effect on subsequent alteration in soil moisture/run off added to the tree's woes.

If there is no evidence of pathogens then the roots may have suffocated and died, lost structural integrity and it didn't take much for the tree to fall.

If the potential contributary factors alluded to are relatively recent the landscape/construction companies may be liable if the tree was meant to be protected during operations. Depends on the legislation you have over there and how it was managed.

[Fungus]

Welcome to give your expertize and clever thoughts on why this oak fell some nights ago!

 

Cilla,

Please post this type of questions next time under Tree Health Care. Without going into what the primary causes of the degradation of the root system were (see Paul Jenks' post), because of the typical lost of major roots (see photo), the pathogen causing the fall of the oak probably was Grifola frondosa.

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[Cilla]

Thanks Paul and Gerrit!

 

I was unsure on where to post this. I didn't check the tree myself either but helped the guy documenting yesterday and I hope that he will continue.

 

I will post him both your comments and pass it over to him until I have time to dig more in it!

 

Thanks again,

 

Cilla

[Tony Croft aka hamadryad]

was the scar on the trunk with the loss of bark caused by the fall or something else?

[Tony Croft aka hamadryad]

The soil level marked on the trunk is too high to be natural, the soil was buit up at some stage hence all the major root death and fine reiterative root system trying to re establish.

[Fungus]

the soil was built up ... the fine reiterative root system trying to re establish.

 

The formation of adventitious roots can also be triggered by the loss of the major roots and buttresses caused by the root parasite, as you can often see happening with Grifola frondosa on oak and Meripilus giganteus on beech.

[Tony Croft aka hamadryad]

The formation of adventitious roots can also be triggered by the loss of the major roots and buttresses caused by the root parasite, as you can often see happening with Grifola frondosa on oak and Meripilus giganteus on beech.

 

absolutely agree, but the cause of the very severe decay and lack of upper surface compensation or tensile triangle (optimisation) in the upper root horizons is due to suffocation (IMO) There is only one fungi I know to cause such a lack of flare and or compensation in the upper root surface and that is colybia.

 

I suspect grifola also would need a reasonable oxygen level as opposed to mellea/ostoyae

[Cilla]

was the scar on the trunk with the loss of bark caused by the fall or something else?

 

Unfortunately we don't know. People are trying to get hold of more pictures of the tree while it was standing. A photographer is living next to it and has numerous of photos.

 

The land raise here was about 1,5 meters, made in the 1950ies. By that one could be satisfyed and think that new or further knowledge is not to be fetched from the situation...

 

But there is always something to learn. At times oaks show much earlier response to fillings, at times they hardly show at all.

[Tony Croft aka hamadryad]

But there is always something to learn. At times oaks show much earlier response to fillings, at times they hardly show at all.

 

 

depends on soil density and other factors, tree health at time of fill ect, these things dont happen overnight, its so hard to prove because of this.