A multipronged research strategy was adopted to better understand how plant cell walls are formed and what controls the composition and properties of lignocellulosic feedstock materials. This study entailed the use of –omics, spectroscopy, sugar release assay, imaging and bioinformatics approaches to characterize a selected set of Populus samples. Spectroscopy studies found Populus tree stem cores collected from natural populations to vary greatly in their cell wall compositions. Salient individuals from this population were employed in sugar release assays. We also characterized wild-type Populus plants under tension stress in controlled greenhouse conditions. Tension wood is a special type of reaction wood that is formed in response to tension/bending stress and is characterized by properties, such as high cellulose content, low lignin content, higher xylem cell number and increased secondary cell wall thickness relative to normal wood. We report here results from the GC-MS –based metabolite profiling of xylem and phloem tissue samples collected from normal, tension, and opposite wood types. A potential set of new candidate genes in cellulose biosynthesis pathway was identified based on co-assessments of the Illumina-based transcriptome and LC-MS/MS proteome profiling datasets. Finally, preliminary results from functional genomics investigations using transgenic Populus plants will be presented.