Fig. 3. The measured gas components of pyrolysis are CO, CH₄, CO₂, C₂H₆, and C₃H₈. As the temperature of pyrolysis increases, tar and char are broken down to smaller C chemicals and gas. There were no differences in component yields between seasonal time of harvest, so data presented are means of Cave-In-Rock switchgrass samples harvested in fall 2002 to spring 2004 from plot-scale fields. Vertical bars denote ± SD.