New equation adds up to better weight estimates for standing timber


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Posted: 3/7/2003


A Mississippi State forestry professor is providing a better way to predict the "delivered” weight of standing Southern pines.

Associate professor Robert C. Parker and other scientists at the university's Forest and Wildlife Research Center have developed a mathematical formula that gives forest resource managers the ability to accurately predict the weight of standing trees very early in the production process.

Parker said the MSU-developed equation, which was tested through extensive field research, should be especially helpful in estimating weight of the green wood preferred by most mills in the hot, humid South for its ability to be stored for long periods with little deterioration.

"There currently are weight functions and tables available to estimate standing trees,” Parker said. "Most predict green-weight immediately after trees are felled, rather than weight once delivered to the wood yard or mill.”

Because of moisture loss, weight differs significantly after delivery to even the first processor, he explained.

The MSU-produced equation predicts the weight of trees at delivery, as well as providing compatible field measures to predict conventional units such as cubic feet, cords and board feet.

In testing their approach, the team began by measuring a sample of standing trees at the university's John W. Starr Memorial Forest near Starkville. Once the trees were felled, more intensive measurements were conducted on the ground.

To minimize operational delays, half the sample trees—designated "full profile” trees—were measured both inside and outside the bark at specified intervals along the stem. The other half—"partial profiles”—were measured only outside the bark on the felled stem at fewer specified intervals.

Parker said the samples then were limbed, topped and moved to the loading site, where they were weighed and measured for stem length and merchantable top diameter—that portion of the tree that can be used for forest products.

"We determined that the full- and partial-profile equations were about the same, meaning that forest resource managers now can take fewer diameter measures and still obtain reliable volume estimates,” Parker said.

The new equation also can be used to predict the weight of any merchantable top-diameter, thus providing an additional tool for forest inventory and administrative planning, he said.

For additional information about the study, contact Parker at (662) 325-2775 or by e-mail at