Dimension variance regularity of lumber processed by roller compression

The green poplars lumbers were compressed radially and tangentially without limit in cross direction under the compression ratio of 10%, 20%, 30%, 40% and 50%, and at normal temperature, respectively. Variance of thickness, width, cubage and variance percent of per-dimension were studied before and after roller process under the conditions of oven-dry, air-dry (MC12%) and green. By comparison with non-roller compression, the instantaneous deformation by roller compression could return back mostly, the thickness variance reduced from −0.154% to −4. 500%, the width variance enlarged slightly from 0 to 3.740% , and the cubage reduced a little from − 0.329% to −3.019%.