Abstract To better understand the within-tree variations between juvenile wood, mature wood, and compression wood, wood from a 35-year-old mature bent loblolly pine was separated into seven groups by different positions in the tree. Morphological and chemical structure analyses, including fiber quality, X-ray diffraction, sugar and lignin content analysis, as well as nitrobenzene oxidation, ozonation, and advanced NMR spectroscopy, were performed. Fiber properties were significantly different for tree-top juvenile normal wood and tree-bottom juvenile normal wood, juvenile normal and mature normal wood, juvenile compression and mature compression wood. However, differences in the chemical structure and composition were less significant within the specific tissues indicated above.