Pine straw, the uppermost forest floor layer of undecayed, reddish-brown pine needles, is raked, baled, and sold as a landscaping mulch throughout the southeastern United States. Loblolly (Pinus taeda, L.), longleaf (P. palustris, Mill.), and slash (P. elliottii Engelm. var. elliottii) pine are the three southern pine species commonly raked for pine straw. The value of pine straw as a forest product is large. Private landowner pine straw revenues have steadily increased throughout the southeastern United States over the past two decades and now total more than USD 200 million. Information is limited on the short- or long-term effects of pine straw removal on foliage production or stand growth in southern pine stands. Results from most published studies suggest that annual pine straw raking without fertilization on non-old-field sites reduces straw yields compared to no raking. Old-field sites often do not benefit from fertilization with increased pine straw or wood volume yields. Though fertilization may be beneficial for pine straw production on some sites, understory vegetation presence and disease prevalence may increase following fertilization. This review addresses pine straw removal effects on pine straw production and stand growth parameters based on recent studies and provides fertilization recommendations to maintain or improve pine straw production and stand growth and yield.

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Efforts to restore longleaf pine across the southeast United States have occurred on two distinct site types, cutover forests and old agricultural fields. We measured wood and bark physical properties of unthinned planted longleaf pine from sixteen stands across Georgia, ages 12 to 25, with eight stands sampled from each site type. Three-hundred and twenty trees were felled and 3,572 disks collected from within the trees. Wood and bark specific gravity (SG), moisture content (MC), and proportion of bark were measured. Non-linear mixed effects models were developed to predict the variation in wood and bark SG with respect to relative height, age, and site type. Cutover sites had higher whole-tree wood SG (0.504 vs 0.455) and bark SG (0.374 vs 0.347) than old agricultural fields. The models explained 50% and 37% of the variability in wood and bark SG, respectively. Moisture content models were fitted as a function of SG for wood (R2 = 0.87) and bark (R2 = 0.71). Bark thickness, dry mass, and green volume were higher for cutover forest sites. Trees sampled included both non-defect and defect-containing trees, however, no significant differences in the wood physical properties were found. These results provide important information for the utilization of plantation longleaf pine.

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