Hi Martina, I enjoyed your post once again.
That fungi look as if it might be Turkey Tail (as we call it here in the U.S.) My niece is using it in tincture form to help support her chemotherapy treatments for a brain tumor, and her tumor has shrunk in size.
I've heard that, it takes a fallen tree as many years as its age to fully break down and return to the earth. I use small branches and twigs in my compost pile to help nourish my soil in the garden. They break down quickly.
I'm sorry to hear about your niece but I am happy that she found something what helps her. I wish I could send her those mushrooms! There were so many!
Oh, I didn't know it! These trees didn't look that old, so it should go fairly quickly :)
I hope it will help to grow a great produce! Do you have a place to grow veggies in winter too?
The size and type of tree, certainly must be a factor.
No, I don't have a winter place to grow vegetables; perhaps some day.