Sulfur shelves are one of the most noticeable fungi. The bright yellow to orange lobed fruiting body, composed of many overlapping shelves, may be up to a foot in diameter. Sulfur shelves can be found growing on a large variety of deciduous and coniferous trees, both living and dead. The most common species of sulfur shelf is Laetiporus sulphureus. Shelves grow directly from the trunk of a tree, without stalks, and tiny pores on the undersides of the shelves produce spores. Shelves typically appear in the summer or fall.
The fruiting bodies of sulfur shelf fungi are annual, which means that they do not persist year to year. When young, the fungus is edible and tastes like chicken, hence the common name "chicken fungus".
The sulfur shelf is a wood decay fungus, and it usually lives for several years unnoticed in a dead or declining tree before producing its brilliant fruiting body. The presence of fruiting bodies generally indicates that there is a large amount of rot within the tree, which weakens the tree and may make it more prone to falling over in a storm. Trees with internal decay that could cause damage if they fell should be assessed by an arborist.
Sulfur shelf fungus on an ash tree.
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