Well this is refreshing--i first came to internet chat forums to learn about fungi and it has taken 6 years to get a detailed reply! Though i am 12 time zones from home and library i'll reply as possible:
" the readers of Tree Care Industry (September 2004) will be primarely based in the USA, so it will not have been noticed by arborists, mycologists, forest ecologists and phytopathologists from European countries."
fair enough, though the cornell u text may have been seen over the pond.
"Then there is the fact, that the field research is primarely based on observations on Quercus species, such Q. alba, Q. phellos, Q. stellata or Q. montana, with tree species specific ecosystems, life cycles and soil food webs, including ectomycorrhizal macrofungi, European researchers are not familiar with."
true enough, though they are still Quercus, in similar landscapes and at similar latitudes. Mycorrhizae may be important but whether they are a determining factor in all pathology is unclear to me.
"Concerning your article, I have the following questions :
- By what method was the presence of soil bacteria and other soil organisms assessed and by what method was the presence of fungal pathogens, such as Phytophthora species and yet unknow pathogens causing Acute Oak Death identified and excluded ?"
No lab assessment done by this humble arborist. I replied on the reference which I consider the best in north america. The fact is in the 100+ infections i have managed there is no wood decay associated with frothy flux (Sinclair/Lyons termed it this in the edition that came out after the article was written, hence my 2004 struggle for the appropriate terminology)
"- Were the tree species specific ectomycorrhizal macrofungi associated with the life cycles of the trees identified and monitored ?
In the course of treatment we add air and OM to the soil to foster these, and observe growth aka informal monitoring, but no names are assigned; beyond my expertise. Clients unlikely to pay for same unless benefits clearly worth the cost. so far the trees recover without such analysis.
- Was taken into account, that the high-nitrogen fertilization
???The lawns these trees grow in are seldom fertilized, and many infected trees are in unferitlized natural areas, so I am not sure what you refer to. At UNC campus they may broadcast some N, and i do agree trees would be more resistant if mulched, but N is not a factor in many cases.
killed the tree species specific ectomycorrhizal symbionts first, which was detrimental to the nutrients and water supply of the tree and left the root system unprotected for invasions of parasites such as Armillaria and soil pathogens, after which Phytophthora "thrived" ?
sorry but the facts do not fit this theory; i'm trained to let facts drive theory. Also, Phytophthora in the se usa is not virulent but often held in check by drying out the lesions and soil replacement. Armillaria when found can also be controlled in the same manner, in my limited experience and by reading accounts of other arborists.
"My experiences with "frothy flux" and the association with rhizomorphs, plaques and/or mycelia of necrotrophic parasitic Armillaria species, which on oak mostly is A. ostoyae, on 150+ Q. robur and 50+ Q. rubra are quite different from yours. To summarize, my research over a period of 15 years has shown, that the "frothy flux" associated with and IMO triggered by the rhizomorphs or plaques of parasitic Armillaria species blocking the floeem and xyleem transport, can at first locally hinder the formation of mycelia, rhizomorphs or plaques, but eventually "eases the way" by providing a pathway or stepping stone for further development of rhizomorphs and/or plaques, which are well protected against acids and aggressive organisms by a layer of melanine.
Wow! well what a difference an ocean makes--again, no wood decay associated; none detected by sounding or tomograph or outward signs or conks or response growth. Infections are treated by removing dead tissue, rinsing with 10% bleach at first but now hydrogen peroxide. Persistent lesions are cauterized with a blowtorch. Closure rates approach 1"/year in most trees. sealants sometimes applied when a lot of xylem is exposed.
Some final remarks to the text and photo's :
- Yeasts are not bacteria, they are fungi (mostly ascomycetes).
yes, misplaced hyphen caused confusion there. Last I heard, Phytphthora was termed a FLO fungus-like organism, too, but that may have changed, and does not seem so important anyway.
"- The rhizoid structures in the fourth photo (page 36) don't look like rhizomorphs to me, but have the characteristics of secundary root formation "tapping" the energy rich ooze
there are both rootlets and what strongly resemble armillaria rhizomporphs--black brittle structures with more perpendicular branching than roots typically do. that image taken near fresh and severe construction damage. insect organisms tap that ooze routinely--seldom is adventitious rooting evident near frothy flux ime. image in pdf is poor--more easily seen in hard copy.
"to facilitate the formation of callus to close the wound, a phenomenon I have often assessed and documented (with photo's) in trees attacked by (rhizomorphs of) Armillaria.
yes adventitious rooting not uncommon around wounds of all origins, or in any dark moist condition where composted OM is present. and i agree the result is faster closure, though it may be teleological to say that was the purpose.
Thanks for the reply: I could learn a lot from European trees, and will next spring.
