Is Cedar an Insect Repellent?

Including Cedar in a stack of sawn wood will not keep bugs away, the Wood Doctor explains. July 11, 2013

Question
I have cut several red maples that are heavily figured and show indication of Ambrosia beetle (purple stars in log ends). One tree milled confirms this fine coloring. I intend to air dry in shed/open barn.

Would it help to layer in some red cedar in stacked lumber to keep insect, like powderpost beetles, away? I have some nice red cedar (aromatic) that could be milled at the same time as the maple.

If I slab these and others that I intend to cut leaving the raw edge, should I remove the bark? I plan to cut in this manner due to extreme burl type growth on sides of trees that look like warts the size of softballs to soccer balls.

Any idea how long it will take to dry if I cut to 10/4 assuming 1500 bdft in stack? I'm in VA and it's now summer.

Forum Responses
From Professor Gene Wengert, forum technical advisor:
The log stain you describe is likely blue stain (fungal) and not from an insect.

The cedar will not repel insects at all. That is a wives' tale.

The bark can harbor insects and does slow drying, so most of the time it would be removed.

It is hard to predict time, but in a good drying situation, I suspect that you will be well air dried in three summer months or maybe four if there is a lot of rain. Use a roof, 3/4" stickers, etc. In any case, follow good air drying practices as written in books like Air Drying of Lumber.



From contributor D:

Gene, back in forestry school at Oklahoma State, 1980 or so, I learned that there was no hard evidence that ERC repelled insects, only people's perception that it does. Since that time I tried to keep up on the latest finding of ERC and bugs. So are you saying that it has been confirmed the ERC does not repel bugs?


From Professor Gene Wengert, forum technical advisor:
I was referring to the use of lumber in the stack to repel insects. The lack of moth repelling properties of dried cedar is documented. However, there is a large industry that uses cedar oil for insect repellants. I do not know if that is proven or not.