April Salt Spring Island Fungus of the Month: Kretzschmaria deusta

Kretzschmaria deusta, also called Brittle Cinder, is a plant disease that kills trees by attacking the roots or base of a tree. The fungus dissolves the cellulose in the wood, but initially leaves lignin behind, making the wood brittle. Infected trees often shatter near the roots and fall over unexpectedly. On Salt Spring Island, it infects mostly bigleaf maples.

Most of the damage is hidden under the bark, but flat grey lumpy fruiting bodies with bright white edges may appear on infected trees or logs in late spring or early summer. As the year goes on, they darken and dry out, coming to resemble crumbly charcoal.

observation by vail

Like last month's Map Fungus, individual fungi colonizing a tree create boundaries between themselves in the form of thin, winding black zone lines, but for Kretzschmaria deusta inside a tree trunk, the boundaries outline three-dimensional fungal territories. When the wood is cut, you can see a cross section of the barriers as dark calligraphy lines on the cut side called "spalting". Woodworkers sometime call wood marked with these lines "webwood".

Photo by Korvinist

Usable wood with spalting is rare, because there is only a narrow time period between when the nearly-invisible fungus has damaged the wood enough to mark it, but before it has damaged it so much it is too fragile to make anything from.

Here is a beautiful guitar made from infected maple wood. I don't know for sure that the infecting fungus is Kretzschmaria deusta - there are a few other plant diseases that also cause webwood and woodworkers don't care which they use - but it certainly could be:

photo by FC Spoiler

There are other fungi that make art of wood as they infect it. Chlorociboria species turn wood blue. Nobody has observed a Chlorociboria on Salt Spring yet, but here's one from Comox:

observation by jbindernagel

I don't know if it can happen naturally, but there are labs experimenting with deliberately infecting wood with multiple fungi to create more complex spalting patterns. This article has some incredible photos.

I hope you've been able to find your way outside in these strange times. Keep looking down!

Julkaistu kesäkuu 1, 2020 05:45 AP. käyttäjältä corvi