Calculating footage based on weight

How to estimate the board feet in logs based on their weight. August 10, 2000

Does anybody have an easy way of determining board footage (BF) based on the weight of the logs in, say, red oak?

All log rules vary; there is no hard-and-fast rule for determining footage from weight. Some rules (Doyle) are very conservative, others (Int'l., 1/4-inch) are pretty liberal.

As rules of thumb go, this is one of the handiest I've come across, but it is far from precise:
1000 board feet of lumber;
1 cord of pulpwood;
1 unit of chips or sawdust;
all contain about the same amount of wood, approximately 5,000 lbs.

There is an excellent book that has lots of tables: U.S. Department of Agriculture Handbook No. 605, Utilization of Hardwoods Growing on Southern Pine Sites. It is available at all libraries through Interlibrary Loan.

One formula given is Int'l. 1/4-inch volume: BF equals 0.09230 (weight of the load of logs in pounds), minus 9.19587 (number of pieces on the load, times 2, if under 20 feet long), plus 420.158

A cord of Appalachian oak weighs 5,760 pounds. A thousand BF of green red oak (1-1/8 inches thick and 2 inches of overlength weighs 5,860 pounds.

Gene Wengert, forum moderator

Here are some numbers that I have experienced:

One semi load of logs weighing approx. 40,000 to 44,000 pounds will average about 3,500 BF (Doyle scale). These diameters are typically between 18 and 24 inches. The smaller the average diameter, the less the footage per pound.

Another way to get a reasonable estimate is to calculate your average diameter (including bark, and an allowance for taper); determine your cubic feet per foot of log; and use 65 or 70 pounds for your weight per cubic foot. Finally, divide by your footage per lineal foot of log, either scaled or actual.