| Whereas the sapwood of southern yellow pine (Pinus spp.) is readily treatable, the heartwood of this species and other species is essentially impermeable to preservatives such as chromated copper arsenate (CCA). Tests at the Forest Products Laboratory indicate that the penetration and retention of southern pine heartwood and Douglas-fir heartwood can be improved by subjecting kiln dried dimension stock to varying levels of compression and/or vibration to mechanically stress lumber. |
