AbstractBonding properties of southern yellow pine (Pinus spp.) and Douglas-fir (Pseudotsuga menziesii) were compared in terms of density, chemical composition, surface energy, shear stress, percent wood failure, and delamination. Specimens were taken from two trees of loblolly pine (Pinus taeda) and one tree of Douglas-fir. Density measurements showed that for mature wood, southern pine exhibited a higher average density than Douglas-fir, but for juvenile wood, southern pine showed a lower average density than Douglas-fir. Chemical analysis determined that southern yellow pine contained higher percent hemicellulose, lignin, and extractives, whereas Douglas-fir had higher percent cellulose. Static sessile drop contact angle measurements revealed that southern yellow pine specimens exhibited a lower average contact angle than Douglas-fir and, accordingly, higher average surface energy. Shear strength, percent wood failure, and delamination due to accelerated weathering were measured for bonded specimens constructed with either a one-part moisture-cure polyurethane (PUR) or a two-part ambient-curing phenol-resorcinol-formaldehyde (PRF) and three different assembly time combinations. Shear strength for southern yellow pine was affected the most by assembly time, whereas Douglas-fir shear strength was affected by the type of adhesive and interaction with the growth region at the bond. Delamination results showed that southern yellow pine exhibited less delamination than Douglas-fir when using PRF. Delamination measurements from the PUR bonds were similar and extremely high for both wood types. Although statistically significant differences were found in a few wood factors, limited differences were found in shear strengths, percent wood failure, and delamination due to accelerated testing for the two wood types.