Wood properties of mature loblolly pine grown in Hawaii, North Carolina, and Mississippi: impacts of climate conditions on specific gravity and chemical composition

Abstract

Higher productivities for loblolly pine (Pinus taeda L.) growing at exotic locations (e.g., Hawaii, Brazil) indicate that the full growth potential of this southern pine species has yet to be reached in plantations across the southeastern United States (US). The higher productivity of Hawaii-grown loblolly pine has been attributed to more favorable climate conditions. To date, physical, anatomical, and chemical property data for loblolly pine wood from exotic locations are scarce. Mid-infrared spectroscopy coupled with multivariate analysis was used to screen for chemical differences between wood samples from Hawaii (HI), North Carolina (NC), and Mississippi (MS). The principal component analysis scores plot showed that the MS samples formed a distinct cluster apart from overlapping clusters for the other two sites. Using standard wet chemistry procedures, we found that the mean lignin content for the MS site (30.1%) was significantly lower than that determined for the NC (34.5%) and HI (33.9%) sites; said lower lignin value was offset by significantly higher glucose and mannose contents. Results on the US mainland were seemingly consistent with the greater formation of latewood at sites with longer growing seasons, and the lower lignin content of latewood relative to earlywood shown for pines. Given the low percent latewood for the HI site (37.2%) relative to both mainland sites (MS, 54.8%; NC, 53.1%), yet similar lignin contents between the NC and HI sites, it appears that the relative lignin value for these exotically-grown loblolly pine trees cannot be solely attributed to the proportion of latewood.