Why are logs kept or stored wet, before being milled?
Question:Driving down the expressway I pass huge stacks of logs. It appears as though they are being watered with sprinklers. Can anyone tell me why this is being done and what they are doing?
Answers:
Yes, leaving logs out will allow some checking on the ends of the logs. And yes keeping wood wet does does make it a lot easier to saw. But wood is watered or put into "hot ponds" for other important reasons. Three very important reason for watering are to keep insects out of the wood, to make removal of the bark much easier and to keep the wood from developing fungus or mold. Insects, fugus and improper debarking can have a major effect on the yield and value of lumber obtained from a log.
As long as bark is left on a log the checking (splitting) of the wood will be minimal as long as the log is sawn in a reasonable amount of time. But leaving the bark on a log creates an open invitation to insects. By saturating the log with water the invitation to the insect goes away and the bark becomes easier to remove when it is put into a debarker.
The water also keep logs from developing fungus and molds. Most softwoods if not watered will develop what is known as sap stain or blue stain. This is a fungus that develops in wood that creates a blue or gray stain.
If the logs are sawn and put immediately into a dry kiln and dried to the proper moisture content insects and fungus are no longer a worry. But if the do not go into a kiln the logs are usually treated with an "anti stain chemical" which will prevent sap stain and usually keep insects away.
the more quickly wood dries, the more likely it is to crack and split. If logs are kept wet before milling, then the cut wood will be less likely to develope cracks.
Dried wood is more likely to crack once milled and cut.
To keep the wood from splitting.
To keep them in a more natural state and prevent them from drying out.
Two reasons. First being that if the wood is allowed to dry naturally as a log, it tends to "check" or crack perpendicular to the grain before it is milled. By keeping the moisture content high, the logs can be cut into lumber and milled, then dried quickly under controlled conditions.
Second has to do with the ease of sawing. The moisture in the wood acts as a lubricant for the saws that cut it into lumber and the machines that dress it. This allows it to move through the saws at a faster rate. Dulls saw blades much less. Also allows for the use of thinner blades which produce less waste sawdust.
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