Cut some Walnut logs from an orchard, waiting until year end to be cut into boards.
They have been stored here in dry Central California and yesterday, for the first time, I notice little holes in the bark. The holes are about 1/2″ deep and I have two in one end, about 1 1/2″ deep. They are mainly on the top sides of the logs.
So far I don’t seem to have real damage, but not sure what to do next?
The holes almost look as if they were drilled. Are these insects, or a bird?
I post some photos and will appreciate any comments.
Willie
Replies
Hello from the great Yolo county. I'm no wood or entomology expert, but I am addicted to sawing up would-be firewood. Here's some observations:
1. The holes are neat and perpendicular to the surface. I'd guess that they are beetles if the hole is about 1/8 th inch or carpenter bees if the holes are about 1/4 inch.
2. The wood is english walnut, not black walnut. Still equally beautiful and workable wood, but lighter brown with more streaking with dark and light along the grain. English is much more susceptible to attack than black walnut. Not even termites like the taste of black walnut heartwood, though they'll chow down on the sapwood. In the great valley, as soon as a branch dies, it's invaded by bark beetles and often the larger carpenter bees. I cut up both types of walnut into lengths that fit in my chest freezer (about 30 inches) and freeze for a week, thaw for a week, and repeat a couple of times. Active larvae (as opposed to eggs or desciated larvae) can't survive freezing. The freeze thaw cycle promotes eggs hatching into a freeze vulnerable state; then, they get frozen.
3. The chunks are still in the round. Differential shrinkage guarantees that they will check (crack) in various places. Before you store the wood, cut it in half. Don't stand the log on end and chain saw perpendicular to the axis - lay it down and groove it along the side on both sides so that the chain saw removes long "worms" of wood, not chips or dust. I'll crack much less if divided in half first. I personally like to then slice the halfs into thick "boards" right away on the band saw and sticker and stack them to dry.
4. These chunks are firewood, not lumber. Unless I have the scale of the photo wrong, they look about 10 inches max in diameter. Firewood. For all but the slowest growing woods, go for 12 - 16 inches minimum diameter will give a reasonable amount of heartwood - the good stuff. 24 to 36 inches is best. Beyond 36 inches in diameter or so, it's too big for old folks like me to handle.
By all means, go ahead and work with this old orchard wood. There's color and grain hidden in some of this wood that will never even be approached in the best lumber yards. Good luck, Mike
Mike,
Thanks, that was very helpful. The logs were cut directly after removal from the ground, about ten weeks ago, around 12 to 14 inches in diameter. The trees were 18 years old.
Is there any other treatment than freezing? Insecticide or something?
Willie
I can't think of any pesticide that I'd be willing to use and breathe sawdust later. There probably are some.
Heat will work as in a drying kiln. But, we cut our own wood so that we can have air dried wood and the central valley is a great place for air drying wood if you're patient.
You could try a heavy plastic bag and some dry ice an a few weeks. That would produce lethal carbon dioxide levels inside that would probably kill active larvae - maybe eggs, maybe dormant larvae. We put dry ice down ground squirril holes in the orchard and cover them right away. It kills the squirrils, though not as well as a frangible 22 cal round. Less waiting though.
Looks like you have some sort of cambium-mining beetle. They'll likely only have eaten sapwood if anything.
Once the wood is milled, sticked and stacked, and the MC gets down below 25, the critters will be gone.
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