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Eric's picture
Which woods work best Kiln drying or Air drying - Protecting against mold/insects

Hi All,


I am recently new to the sawmilling world.  I just bought my MN26 the end of last year and am learning the great amount of information everybody has posted to this forum which is awesome, many thanks to everybody.  I'm from western Ohio and have a family farm in eastern Ohio.  I have been a woodworker starting when I was a kid carving spoons, bowls etc.  I have always loved to work wood and built things, am have finally been able to make my sawmill dream a reality.

I hope not to repeat too much info from other posts, but am wondering which woods are highly recommended to Kiln dry, to protect against molds or woods highly susceptable to powderpost, and which woods work well to air dry.  Fortunatley, kiln drying is an option for me as I have located a friend who will rent me space in his kiln.  I have made plenty of firwood in my life and have found that some woods get hit hard with powderpost beetle like hackberry for example.  I also understand that others like Sycamore are very prone to molding.  How successful does bark removal work in keeping the beetles at bay?  Have people had much trouble with powderpost attacking your lumber piles?

Can the time of year that you saw affect some of these issues?  Less mold if sawn in dry winter air?


Any info on the subject would be much appreciated.




Bill's picture

Hi Eric, welcome to the forum . I don't know nothing about those kinds of logs surprise but around here there's always a lot more moister in the tree cut in the spring than late fall or winter. If you wish to peel a log spring is the time to fall them. 



eddiemac's picture

Congratulations on your new mill.  There are beetles that attack green wood (bark removal helps against them), and other beetles (lyctid powder post beetles) that are only interested when the wood gets relatively dry.  Lyctid p.p. beetles are the dreaded ones because they infect, hatch, and reinfect dry lumber.  Some people protect their lumber as soon as it is cut by spraying borax solutions on every board.  Even if you kiln dry to bug-killing temps, p.p.b.'s can make their way into your lumber at a later time.  If your logs are cut from trees which are dead already, you'll have more insect problems.  Trees cut in warm weather are more vulnerable because that's when insects and mold are active; winter is an ideal time to air-dry lumber.  Hackberry is easily infected by p.p.b's.  The sapwood of white oak (especially if from dead standing trees) sometimes attracts the wicked critters, and red oak is prone to infestations, as are hickory and ash.  The only problem I've seen in red cedar is worms in the sapwood; so except for that, cedar drys quickly and without problems.  I have seen p.p.b. holes in walnut, but that's pretty rare.   Yes, I have had problems with powder post beetles.  Good housekeeping helps.   Remove all decaying debris and any lumber showing signs of powder post beetles (I'm talking about the really small holes; the green wood beetles have larger holes) from the millyard and lumber storage areas.  As for how easy it is to dry, "Sawmill & Woodlot" magazine published an excellent series of information pages on most of the common tree species explaining recommended drying procedures, etc.   --   still available from their site.

Post Oakie
Post Oakie's picture

Eric, welcome to the forum, and congratulations on your sawmill!  Your best line of defense is to cook the little buggers.  Heat the wood to at least 135 deg F long enough for the core of the wood to reach and hold that temperature for at least an hour-- I'd hold the temp for at least three hours for 4/4 lumber, just to be safe.  Reinfestation is always a possibility as Eddie says, though not likely once you get the wood under 8% moisture content.

Eric's picture

Thanks everyone.  Thats good advise.  I suppose stacking your lumber next to your firewood piles probably isn't a good idea either.  I think I might go ahead and pay for a subcription to "Sawmill and Woodlot", thanks eddiemac that looks really interesting.  

How safe is borax solution if your going to be planning cutting your boards for woodworking projects?  I suppose it would be fine if your using borax spraying boards for building/siding.

It sounds that the quicker you mill your logs the better and you may take a little more risk with dead trees having more insect issues.  I should be careful where I stack all of my ash lumber.  Ash logs are plentiful here in Ohio for the time being.  I was able to saw about a dozen ash logs last Sat. and am feeling much more confidient in running the mill.

eddiemac's picture

Funny you mention it.  Because my wood-heated shop is connected to the millyard, I have a firewood pile between my lumber stacks and the wall of my wood shop.  (Some people never learn).  I make sure there is no firewood left from one season to the other, cross my fingers, and hope for the best.  I think the borax solutions (Timbor is one of them, if I remember right) are pretty safe  -   the issue has been thoroughly discussed on the on-line sites, Forestry Forum and Woodweb.  With regard to ash, the S&W pages I referred to above say "Ash is very attractive to a variety of insects when drying.  Although air drying is not suggested, if used, air-drying yards must be kept free of wood debris that would encourage the ambrosia beetle and anobiid beetles.  Once lower MCs [moisture contents] are achieved (8-30 percent MC), the lyctid powder post beetle is a risk; any infected lumber and plywood, and any debris from other species, must be kept separated from ash even in dry storage."

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