Models to predict whole-disk specific gravity and moisture content in planted longleaf pine from cutover and old field sites

Abstract

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.

Image Analysis To Assess Wood Variability In Longleaf Pine Cross-Sectional Disks

“…Trees were classified as defect-free (no visible stem defects), or defect-containing (herein referred to as defect trees) ie fork, excessive sweep, or ramicorn branching present. From each stand, 20 trees were felled, with up to six defect trees sampled based on the frequency of defect trees within each stand (Raut et al 2022). From each stand, a subsample representing all of the defect trees sampled, and three defect-free trees representing a suppressed (small), codominant (medium), and dominant (large) tree were selected and used for the study for a total of 104 trees.…”

Optimal Forest Management of Even-Aged Longleaf Pine Stands with Nontimber Benefits

“…Longleaf pine ecosystems are critical for the biological diversity of the region by providing habitats for several endangered species, such as the red-cockaded woodpecker, gopher tortoise, and Florida pine snake, and by hosting more than 100 vascular endemic plants (Kirkman and Myers, 2018). Longleaf pine forests can produce higher-quality forest products and provide higher rates of carbon sequestration compared to other southern pines (McNulty et al, 2018;Raut et al, 2022). Furthermore, longleaf pine forests are more resilient to natural disturbances and fluctuating climatic conditions (Koontz et al, 2020;Sharma et al, 2020).…”