Veiled Polypore

The veiled polypore looks like a row of small, cream to tan nuts or marbles stuck to the bark of a recently dead conifer. Turn one over and you will not see the usual spongy pore surface of a shelf fungus. Instead, a whitish skin seals the pores inside a hollow chamber, with a small hole that opens as the spores mature.

That sealed chamber is the key to its life story. Air currents cannot reach the spores, so the fungus relies on insects. Wood-boring beetles crawl in through the opening to feed on the spores and pore tissue, get dusted with spores, and carry them to the next freshly killed tree. Researchers have suggested that the White-headed Woodpecker, which hunts those beetles, may spread the spores too.

It is one of the first decay fungi to move into a tree after death from bark beetles, fire or other causes. It usually appears the year after the tree dies, sometimes by the hundreds up a single trunk, and is rarely found more than a year or two later. It rots only the outer inch or less of sapwood, and it does not kill living trees.

Around Mt. Hood, watch for it on fir, pine, Douglas-fir and hemlock snags in old burns and beetle-killed patches. On Douglas-fir it is a handy clue that bark beetles killed the tree.