A log scaler examines cut timber to identify the amount of good, usable lumber that can be obtained from the wood. Species identification, dimensions and defects are all noted by the log scaler. Calculating a gross scale as well as a net scale, the log scaler factors any defects from the log and eliminates a percentage of the wood to waste in the net scale figure or usable wood calculations. In order for the scaler to maintain the scaling certification, a non-bias scaler will occasionally rescale a log that has been scaled, and the factors must fall within a predetermined percentage of each other.
A timber buyer uses certain methods to identify which trees he wants to buy from a standing timber growth. Once cut, the scaler examines and marks the trees for the species, the estimated wood in each log, as well as any defects in the log. This is the defining method of setting a price to the cut timber. The log scaler keeps a detailed record on the lumber from the time of harvest to the sale of the log or the cutting into dimensional lumber of the log at a sawmill.
Many internal defects that can reside within a log are identified by certain external markings on the log, so the scaler must be alert and very well-trained in order to observe the signs that a problem might exist with any given log. While many logging companies employ a scaler, it is often an independent scaler who sets the price of timber cut. This eliminates the possibility of any miscalculations of the wood or the incorrect pricing of the logs. It is typical for a lumber buyer to compare the findings from his company's log scaler to those of the independent scaler to verify the price charged for the lumber.
There are three commonly used methods of scaling lumber: ramp scaling, where the logs are scaled while loaded onto trucks; roll-out scaling, where each log is rolled off of the truck and onto the ground to be scaled; and standing timber scaling. Of the three methods, a scaler is able to obtain the best view of the logs in a roll-out scaling process. This is also more expedient for the trucks, as they simply empty the logs and drive off. This roll-out method also makes it easier for the log scaler to see signs of internal problems by providing access to more of the log's surface.