lumber core

lumber core, stave core

Wood core consisting of narrow strips of lumber edge-glued together; usually held in place by veneer which is glued to both faces with the grain of the veneer at 90° to that in the core.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
MDF-XPLY weighs 30% less than traditional PB/MDF but is stronger, the company says; it is also available in a solid lumber core center lightweight panel.
Therefore, MC = 20% was used as the wet-limit for which it can be assumed that the lumber core is below FSP.
MDF-XPLY is also available in a solid lumber core center lightweight panel.
In 1963 veneered table tops were normally constructed using hardwood plywood with a lumber core; by the 1980s particleboard and other composite substrates had replaced lumber.
Lumber core, MDF and flake cores also are available in select popular sizes.
manufacturers in the early 1950s as a replacement for lumber core in plywood manufacture.
Davis began selling glued-up, planed lumber core in 1949.
Again, I see no reason for lumber core in your case.
Substrates: PB, MDF & stave lumber core Circle #309
This way, the veneer layers effectively restrain the lumber core because of:
"Highly figured burls and fancy face veneers with lot of different grain directions are hard to stabilize applied to a lumber core. Using particleboard cores adds to the stability of the piece."