Variability in the composition of short rotation woody feedstocks

This paper discusses the variability in chemical composition caused by clonal, geographical, and environmental effects on short rotation woody feedstocks, mainly hybrid clones of poplar. The concentrations of major and minor components have been determined by chemical analysis and pyrolysis molecular beam mass spectrometry (PY-MBMS). The chemical composition was determined for a sample set consisting of debarked wood chips from three clones of deltoides x nigra (DN) and one clone of tristis x balsamifera that were grown on four replicate plots at two locations in Wisconsin. The composition of the wood chips determined by chemical analysis and Py-MBMS showed that the tristic clone was significantly different from that of all the DN clones. The composition of the DN clones studied in this sample set were relatively similar to other hybrid poplar samples that have been analyzed over the past three years. The level of compositional variation due to clonal, geographical and environmental factors observed in short rotation woody species to date indicates that they are a consistent and stable feedstock for biofuels production. The effects of storage on different short rotation woody crops has been studied. Results of the analysis of fresh and stored hybrid poplar using traditional wet chemicalmore » analysis showed differences in the chemical composition of the feedstocks because of storage. Also presented are results from a rapid analytical technique using pyrolysis-mass spectroscopy combined with multivariate statistical analysis to assess the influence of storage on the composition of different short rotation feedstocks. Because of the rapid nature of this technique, a large number of samples could be screened to determine the extent of degradation throughout the piles. The application of this technique to the samples in this study indicated changes in chemical composition occurred during the storage period.« less