Tips for creating spalted maple

Creating spalted lumber by creating the correct conditions. January 4, 2001

Question
Is there a way of making spalted hard maple? I have a log with big hunters spikes in it (never had any luck getting them out) and it is probably well stained by now. If I could get it to spalt, I could chainsaw it into chunks for wood turners.

Forum Responses
Find a cool shaded spot and let it sit on the ground. Cover it with sawdust and keep it moist (not too wet). I can't tell you how long it will take. It will only spalt at temperatures from 60-90 degrees. It’s tricky to catch it just right before it rots. I haven't tried to do it on purpose, but get a lot by accident. Check it after about 3 months.

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A wood turner I know leaves chunks of maple strewn around his yard in order to get them to spalt. He checks them every so often, and when the spalting reaches a stage he likes, he turns the piece and applies the finish.

I found some nice spalted maple at a friend's house, grabbed a few chunks, and 2 months later I went back to get some more--all of the remaining log had rotted. There is a very fine line between great spalting and rotten wood.

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From Gene Wengert, forum technical advisor:
The previous comments are indeed very accurate. Spalting is the result of activity by the white rot fungi. (Shitakii is one white rot fungus, so think twice about how delicious these mushrooms are on your next piece of steak!) You want the fungi to begin their activity, but not get too far advanced. We can stop their activity by drying the wood or by heating it above 130 F. We can encourage their activity by keeping the wood warm and fairly wet (but not too wet).

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The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor A:

I've had some relative success at making spalted maple after reviewing some online articles and tips. I'm in Southwestern Ontario, Canada and this summer (09) has been less than ideal for the conditions required for spalted maple and less than typical for our summer temps. It was a very wet summer and well below average daily temps all year. We usually get mid 30's with high humidity levels but this year we've had three days in the 30's and most days were mid to low 20's, Celsius of course.

I took a piece of 8/4 silver maple, 20"x12", and on June 10 put the maple in my backyard under some very large pines. I laid a bed of wood chips from my dust collector system, watered them lightly from a watering can, laid the maple down and covered with the chips, again sprinkling them with water. The chips are black cherry, walnut and white oak. I never added another drop of water to heap all summer. I pulled them piece of maple out this week, on Sept 10 and let it air dry for five days as it was soaking wet. I brought it in and put it through the jointer and planer to check on the results.

I was quite pleased with what I found actually. There were no definitive black pencil line marks that were present on the edges but the entire piece was well colored with purples, yellows and greens. I think the piece was well on its way to becoming spalted but with the temps dipping to single digits at night and about 20 degrees Celsius during the day I figured the process was going to slow considerably.