Hi Ian,
'ectomycorrhizal macrofungi such as Scleroderma citrinum, Paxillus involutus,
Thelephora terrestris and Boletus badius, that do not seem to have lost their
capacity to (temporarely) live as a saprotroph on and fruit from dead wood
while "awaiting" to colonise the roots of a new partner and seem to refrain
from retracting sugars for producing fruitbodies from the seedling and young
tree partner until the tree can "stand on its own feet" by developing the
foliage needed to produce enough energy (reserves) through photosynthesis to
support itself and its tree species specific ecosystem, and can "afford"
sharing the sugars with its symbionts, the mycelia need to fruit.'
As with endophytic fungi, would you regard the subtle decline within an
ailing tree to trigger the growth, for example of Piptopurus betulinus on a
Birch, to be possibly caused by a reduction in sugar/sap levels? The complete
opposite perhaps of what you're suggesting where an ectomycorrhizal fungi
fruits when sensing a rise in sugar levels prompted by the establishment of a
tree....
1. Ectomycorrhizal macrofungi also "panic fruit" and become parasitic by
withdrawing more sugars from a tree than it can afford (oaks without foliage
with Russula amoenolens fruiting on the 6th of June instead of in
September/October) when the tree is under constant and severe stress (Quercus
robur : suffering from drought and from nitrification with loss of tree
species specific ectomycorrhizal symbionts as a result => 100 % defoliated by
caterpillars, including OPM => then 30 % loss of energy production because of
oak leave mildew on the secondary foliage) and the delicate balance of the
tree and its ectomycorrhizal symbionts is severely disturbed for two or more
years in a row.
2. I know of no evidence of this hypothesis, but I would not be surprised if
this turned out to be the case and the with decline associated diminishing
effectiveness of the defensive system of living tissues would play an
important role too.
Regards,
Gerrit
--
The UK Tree Care mailing list
To unsubscribe send mailto:uktc-unsubscribe@xxxxxx.tree-care.info
The UKTC is supported by The Arbor Centre
http://www.arborcentre.co.uk/
