Mapping variation of handsheet properties within loblolly pine trees

Abstract

Within-tree variation of four handsheet properties (burst index, sheet density, STFI short-span compression strength (STFI) and tensile index) was mapped for loblolly pine trees aged 13 and 22 years using NIR predicted handsheet property data (representing an average of 18 trees for each age). All within-tree maps were similar demonstrating a radial decrease in handsheet properties at all heights, with sheet density and tensile index having the greatest within-tree variation. The corewood zone had the highest values for all properties, while the lowest values were observed in a region consistent with juvenile and transitional outerwood as defined by Burdon et al. (2004). The maps are also similar to, but the inverse of, maps reported in prior studies for density and tracheid coarseness and wall thickness. Relationships amongst the examined handsheet properties and wood and tracheid properties explains the overall similarities of the different maps. The maps provide a representation of within-tree variation of important paper properties at two different ages. An understanding of how these properties vary within loblolly pine trees can aid in better utilization of forest resources.