|
An expanded Web version of segments seen on CNN When crooked boards go straight
Computerized saws help make the most of curved trees
July 25, 1997
Web posted at: 8:22 a.m. EDT (1222 GMT)(CNN) -- Any experienced sawmill operator will tell you that crooked trees are a problem. Most houses are framed with boards made of soft wood, like pine -- boards that need to be straight. But many pines aren't perfectly straight. Even a slight curve in the trunk can seriously reduce the amount of lumber that sawmills can get out of a log.
The solution? Cut curved boards instead -- a process possible only recently, thanks to advances in sawmill technology.
Before the cutting begins, a computer takes a close-up look at each log, deciding how to get the most lumber from each piece of raw wood.
"We have scanners that take a picture of that log in increments down the log and consider the shape, the diameter of the tree, and then calculate what the maximum yield out of that tree would be," said Al Hopkins of Georgia-Pacific Corp.
Computerized saws cut two flat, parallel edges along the log. Then, instead of cutting a straight line against the curving grain, the saws maneuver within the wood, following the grain.
As Hopkins explains, the result is full-length boards for the full length of the log. "That equates to higher yield and higher value," he said.
(111K/10 sec. AIFF or WAV sound)
The boards come out of the saws curved but can be dried straight.
Al Hopkins explains why saw mills are working harder to maximize wood production 187K/17 sec. AIFF or WAV sound His team correctly guessed that the converse of that would be true as well. Slightly bowed lumber, stacked and dried straight, does in fact stay straight.
It sounds like extra work, but it's well worth the effort, Hopkins said.
"Because trees and timber have become more valuable than they once were, it's encouraged people to put more management effort into it. Therefore they're getting more volume per acre, better wood characteristics, better growth than we got, say, 20 years ago," he said.
Georgia-Pacific's two curved saws are among only a handful in operation. The machines aren't cheap, but the company feels the extra board feet they reclaim from the sawdust pile justify the price tag: The cost of the tree accounts for up to 70 percent of the cost of a piece of lumber.
Correspondent Dan Ronan contributed to this report.
Related sites:
Note: Page will open in a new browser windowExternal sites are not endorsed by CNN Interactive.
Sound off on our message boards
Tell us what you think!
You said it...
© 1997 Cable News Network, Inc.
All Rights Reserved.