Flash pyrolysis products from tobacco stalk and yellow pine wood obtained in a pyrolysis apparatus were analyzed. Comparison of pyrolytic products' structural components indicates the origin of each product. Methanol mainly arises from methoxyl groups of uronic acid and from the breakdown of methyl esters and/or ethers from decomposition of pectin-like plant materials. Acetic acid comes from the elimination of acetyl groups originally linked to the xylose unit. The yields of char products from the tobacco stalk and yellow pine wood samples decreased from 33.9% to 23.0% and from 29.2% to 17.0% when final pyrolysis temperature was increased from 675 to 1025 K, respectively. The yields of gaseous products from the tobacco stalk and yellow pine wood samples increased from 25.0% to 40.2% and from 29.7% to 42.5% when final pyrolysis temperature was increased from 675 to 1025 K, respectively. The yields of liquid products from both samples increased with increasing temperature from 675 to 875 K and then decreased. The maximum yields from the tobacco stalk and yellow pine wood samples were 43.0% and 48.7% at 875 K, respectively. The maximum yield of liquid product from the tobacco stalk was 44.5% at 775 K for a 40% Na2CO3 run. Increases and decreases of the yields of liquid products for the tobacco stalk samples were considerably irregular. The maximum yield of liquid product from the yellow pine wood was 44.6% at 775 K for a 50% Na2CO3 run. The maximum yields of acetic acid from yellow pine for nonalkali and alkali runs were 13.85% and 16.58% at 825 K, respectively. The maximum yields of methanol from tea waste for nonalkali and alkali runs were 6.42% and 8.81% at 875 K, respectively. The yields of 1-hydroxy-2-propanone from yellow pine for nonalkali and alkali runs increased from 7.32% to 10.81% and from 7.40% to 12.13% when pyrolysis temperature was increased from 675 to 875 K, respectively.