Hello,

if you mean an age of a fruit body, just count the number of the hymenium layers. Every year the perennial fruit bodies of Fomes spp. produce a new layer of hymenium.

Not the precise count of course, as it depends of the environmental conditions, but still the approximate age of a fruit body can be calculated.

I did some work a few years ago on how long agaric fruit bodies last in the wild in a temperate woodland - Richardson, M.J. (1970). Studies on Russula emetica and other agarics in a Scot’s Pine plantation. Transactions of the British Mycological Society 55, 217-229. I think you might get a pdf on this site. You might get an estimate for brackets like Fomes by periodic measurements, and there will be zoning on the surface, or distinctly separate layers of tubes, that may have some use in aging, but you would need to find out what that means in terms of seasonal growth.

Michael Richardson Many thanks, really appreciate your inputs regarding my question.

For Fomes sp, you can guess the age from the hymenium layers on the fruit body just like Maria V. Kozlova suggested