| 摘要 |
<p>A method of predicting warp of lumber that might be sawn from any given log is disclosed. The method involves measurement of stress wave velocity in the tree stem, either as a standing tree or felled log. A scan is then made to define the exterior geometric configuration of the log. In particular, measurements relating to lack of longitudinal axis linearity (sweep) or irregularity of cross section s of the log are important. Stress wave values and selected geometric parameters are entered into a multivariate regression equation to predict warp propensity of lumber that might be sawn from the log. Separate equations are required for each species for prediction of crook and bow. The equations are originally derived by examination of a representa-tive population of logs of the particular species and locale and measurement of warp in lumber sawn from the logs. The stress wave information may be combined wi th the geometric characteristics in the computer associated with a log scanner at the green end of a sawmill. Logs determined to produce warp prone lumber can be iso-lated and used to produce other products such as timbers or plywood wher e warp is not as critical.</p> |
