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Veterinaising young trees - Pollards with standards

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11 hours ago, tree-fancier123 said:

Gano and all the other fungal nasties. The tree equivalents of small pox and bubonic plague.

Nonsense! You can't anthropomorphise the relationship between trees and fungi, and can't reduce it to 'good' guys and 'bad' guys...

Trees and decay fungi have evolved together over millennia, and while it is disappointing to lose individual valuable trees to the likes of Ganoderma (and as a TO I've lost a few on my patch) there's no point getting hysterical about it.

Incidentally, the '87 hurricane was a lightbulb moment for arboriculture, when it was realised that hollowed trees were more resilient to windblow than non-decayed stems.   

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5 hours ago, Willowboy said:

there's no point getting hysterical about it.

I didn't think I was - just seems to me certain dippy hippy types think tree biology and fungi is all 'circle of life' organisms co-existing in the ecosystem for mutual benefit, symbiotic rather than pathogenic fungi?

 

5 hours ago, Willowboy said:

Incidentally, the '87 hurricane was a lightbulb moment for arboriculture, when it was realised that hollowed trees were more resilient to windblow than non-decayed stems.   


possibly, but beyond a certain extent - 70% cited below in an abstract from Biological Letters, the hollowing definitely leads to failure.

'A survey of previous research of the effects of trunk hollowing on the structural failure of trees found strong agreement across studies, involving a broad range of different species and broad range of tree sizes, that there was a critical amount of hollowing above which structural failure was considerably more likely [13]. This critical point occurs when the radius of the inner hollow region is approximately 70% of the total radius of the trunk. Hollowness less than this critical amount involves very little cost in reduced structural stability. This 70% critical value is broadly used in the management of trees, and in particular is a very widely used criterion for the removal of trees considered to be structurally at risk [14], although its theoretical basis is an area of still-active discussion [15].'

 

the author hypothesizes that trees dont expend energy fighting heartwood decay because the energy is better spent growing and reproducing  - you seemed to suggest that in some way these hollowing fungi were doing the trees a favour

 

 

 

http://rsbl.royalsocietypublishing.org/content/10/11/20140555

 

 

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3 hours ago, tree-fancier123 said:

I didn't think I was - just seems to me certain dippy hippy types think tree biology and fungi is all 'circle of life' organisms co-existing in the ecosystem for mutual benefit, symbiotic rather than pathogenic fungi?

 


possibly, but beyond a certain extent - 70% cited below in an abstract from Biological Letters, the hollowing definitely leads to failure.

'A survey of previous research of the effects of trunk hollowing on the structural failure of trees found strong agreement across studies, involving a broad range of different species and broad range of tree sizes, that there was a critical amount of hollowing above which structural failure was considerably more likely [13]. This critical point occurs when the radius of the inner hollow region is approximately 70% of the total radius of the trunk. Hollowness less than this critical amount involves very little cost in reduced structural stability. This 70% critical value is broadly used in the management of trees, and in particular is a very widely used criterion for the removal of trees considered to be structurally at risk [14], although its theoretical basis is an area of still-active discussion [15].'

 

the author hypothesizes that trees dont expend energy fighting heartwood decay because the energy is better spent growing and reproducing  - you seemed to suggest that in some way these hollowing fungi were doing the trees a favour

 

 

 

http://rsbl.royalsocietypublishing.org/content/10/11/20140555

 

 

First off, I think that it's great that there is thought and discussion about the effects and relationships between trees and fungi. Anyone posing these types of questions is indicationing a their thirst to gain knowledge in the whole science of arboricultural. So I wouldn't take offence at anyone rebutting your ideas.

 

I haven't followed the link you've posted yet, but your extract paraphrases Matthecks t/R ratio (and we all know the arguments about that!) I'd argue the hypothesis that 'trees don't expand energy fighting heartwood decay', in that they have very limited means to do so, Heartwood/ripewood is non-living, so the defence mechanisms are limited to the chemical barriers already present. They can't create defensive walls against internal decay, it's a physically  impossible task because of the way trees grow. 

 

It isn't hippy dippy to understand, or to begin the understand, the bigger picture that all the different, symbiotic and parasitic, fungi play within the ecosystem. Yeah, it seems a big deal when a big tree that's prominent in the landscape is lost because of colonization by gano/armillaria but in the scheme of things, is it really?

 

A few years ago, a group of us students at college were discussing the outbreak of Chalaria. Fresh with the knowledge that Ash constitutes the second most commonly planted deciduous urban tree in the UK, we concluded that it was a disaster. Our tutor disagreed.

 

Look at the bigger picture. 1-5% of ash are likely to be immune or tolerant to the fungus, they will survive and reproduce to create a species resistant to Chalara. Okay it might take 200 years for that population to mature, but it's more than likely to happen. In tree terms it's one or two generations, no time at all in the continuation  of the evolution of the species - but to us!

 

So if a pathogenic fungus cause a early loss of probably less than 5% of urban trees, does it really matter? Would time be better spent managing the tree stock better, pruning less, creating smaller wounds, preventing root damage by utility installations/highway contractors, planting more tree (more diversity/age classes) and creating a better understanding of tree needs and benefits generally?

 

I'll get off me soapbox:D

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Apparently it took 40 million years for a fungus to evolve which could degrade wood? Something around that figure i was told once.

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