Fungus

I have. I have even stopped monitoring some of my former researched forests and woodlands, because visiting them to often could lead to depression. This year I'm moving to another part of the country to escape from witnessing hundreds of oaks and beeches dying because of the effects of excessive nitrification.

Rob, Especially in the eastern and southern parts of the country because of the extreme density of pig and chicken farms (nitrification, OPM) and what do you mean with the "de groote" area ?

So the fierce reduction of the crown was done more than 10 years ago ?

In The Netherlands, we don't have natural and sound environments (anymore).

This looks like a combination of sun scald after (too) heavily pruning followed by the typical necrosis of the cambium and shedding of the bark because of an infection with Armillaria mellea.

Because apart from willows, we lack the tradition of coppicing and pollarding trees and "managing" them to survive the harsh conditions of our "modern" society.

I called Neville Fay Nigel.

Rob, 1. Neither am I and so do I. 2. ... and best without us : even a crack in the pavement can facilitate the development of a forest.

It sure is, Mr Humprys .

David, Nice . IME in spring it more often (partially) is the anamorph Ceriomyces aurantiacus.

Rob, And that's why we don't have any veteran trees or trees over 350-400 years old at all in my country .

Yes, although not very often, I have. And once the tree has fallen, H. annosum often fruits from the entire length of a stem or trunk with soil contact.

According to Nigel Fay, Ted Green and Jill Butler, all British veteran oaks, beeches, ashes, Castanea and Carpinus are pollards, that would not have survived nor become a veteran if people would not actively have "managed" the trees by cutting "bits" of them.

Probably not a Pleurotus species then, but a Hohenbuehelia species (see hidden forest nz fungi : Pleurotaceae)

If it is a Phellinus, it must be P. vorax, but I vote for Tony's suggestion : Heterobasidion annosum.

Cilla & Björn, See my Quercus robur and Collybia fusipes thread.

Cilla, Also see my Quercus and Grifola frondosa thread.

Tony, 1. If possible, we remove all the major roots. And if the neighbouring trees in a row are so close that most of the major roots mix or graft with the infected roots, we also remove both neighbouring trees as a preventive measure. 2. It's a rough estimate from practice that is altered if circumstances call for it. With deep rooters it goes deeper than 0.6 m, with shallow rooters it stretches further than 4 m. In road side verges it can be 3.0 m x 5.0 m. 3. It often is, but it's not activated until circumstances change dramatically (air and water pollution, drought, years in a row of complete defoliage by insects, compaction, pavement alterations, road salt, cable work) and the damaged roots loose their protection by mycorrhizae as a result of this. 4. In forests, it's not primarely a recycler, but a parasite accelerating the death of a tree that has become a parasite of its own tree species specific ecosystem. Armillaria doesn't contribute much to the recycling process in forests, it is done by lots of other macrofungi, that decompose the wood in a succession of saprotrophic macrofungi more or less exclusively associated with the tree species involved. 5. Not with the thousands of infected beeches and oaks in roadside verges and lanes in urban and rural environments with far from complete tree species specific ecosystems and soil food webs to adequately "feed" and protect them. We often even have to choose to fell and remove entire lanes or rows of roadside trees and wait for replanting for five to ten years. Within the rural community where I live, we have over sixty thousand 80-100 years old road side oaks, that are not only suffering from Armillaria and other fungal pathogens, but also from complete defoliage by OPM and other moths. Also see my beech and honey fungus thread, my Quercus robur and Armillaria ostoyae thread and my album on rhizomorphs of Armillaria.

Study shows red oaks grow 8 times faster in central park due to urban heat island effect.

Could you cite scientific articles on the effectiveness of your methods of drying out and otherwise treating Armillaria infections on white oaks from the US and Canada ? And are you familiar with Kelley, Fierke & Stephen (2009) Identification and distribution of Armillaria species associated with an oak decline events in the Arkansas Ozarks (For. Path. 39, 397-404) and Brazee & Wick (2009) Armillaria species distribution on symptomatic hosts in nortern hardwood and mixed oak forests in western Massachusetts (Forest Ecology and Management 258, 1605-1612) ?

1. Could be due to compaction and suffocation, but that could have been adequately compensated by the tree after 60 years if the colonization of the root pathogen had not taken place. And Collybia fusipes could also be a candidate , although it's not very common and on the Swedish fungal Red List classified as not threatened. 2. There's always enough oxygen in the cavities in between the major roots for the mycelium of Grifola frondosa to develop and fruit.

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.

I'm not talking about the microscopical features or characteristics of barriers or the black tree based defensive or fungal territorial demarcation lines, I'm just describing what can be seen in your photo without using a microscope.

1. What about the cause of the black oozing then ? 2. No, your "methods" are not part of Dutch arborists' practice. Besides how do you think this can be done effectively if we are talking about thousands of beeches and oaks infected with parasitic Armillaria species of which oaks are also living under the ever increasing heavy burden of attacks of insects such as OPM or other moths (defoliation) and oak leave mould also associated with nitrification and both beech and oak suffer from drought ? Ever heard of a combination of factors or multicausality making the in vitro "one on one" research you wish for impossible ? 3. Over 90 % of my research on parasitic Armillaria infections on beech and oak is on roadside trees and/or trees in lanes in urban and rural environments and on extensively managed estates, but - of course- assessed and monitored by a mycologist and forest ecologist specializing in the tree species specific ecosystems and life cycles of indigenous trees including the role of ectomycorrhizal symbionts in the defensive system of the trees. If arborists can not assess trees from that perspective, that seems to be a limitation they have in prescribing care for landscape trees. 4. If you were at least a bit familiar with the causes and effects of nitrification on the European continent you would not ask this question.

Did you read my posts on the prevention of spreading of rhizomorphs ?