Wood composition and energy content in a poplar short rotation plantation on fertilized agricultural land in a future CO atmosphere

摘要

To study the influence of elevated CO and nitrogen (N) fertilization on wood properties and energy, Populusxeuramericana trees were exposed to ambient CO (about 370 omol molp# CO) or elevated CO (about 550 omol molp# CO) using Free Air CO Enrichment(FACE) technology in combination with two N levels. Elevated CO was maintained for 5 years. After three growing seasons, the plantation was coppiced, one half of each experimental plot was fertilized and secondary sprouts were harvested after two growing seasons. Fourier transform infrared (FT-IR) spectra of wood revealed significant effects of both elevated CO and N fertilization on wood chemistry, in particular, significant increases in lignin and decreases in N content. These results were corroborated by chemical analysis. Neither elevated CO nor N fertilization affected the calorific value of wood, which was 19.3 MJ kgp#. N fertilization enhanced the energy production per land area by 16-69% because of higher aboveground woody biomass production than on nonfertilized land. Estimates indicate that high yielding poplar short rotation cultivation may significantly contribute as an alternative feedstock for energy production.