Char samples were produced from pyrolysis in a lab-scale solar reactor. The pyrolysis of beech wood was carried out at temperatures ranging from 600 to 2000 degrees C, with heating rates from 5 to 450 degrees C/s. CHNS, scanning electron microscopy analysis, X-ray diffractometry, Brunauer-Emmett-Teller adsorption were employed to investigate the effect of temperature and heating rate on char composition and structure. The results indicated that char structure was more and more ordered with temperature increase and heating rate decrease (higher than 50 degrees C/s). The surface area and pore volume firstly increased with temperature and reached maximum at 1200 degrees C then reduced significantly at 2000 degrees C. Besides, they firstly increased with heating rate and then decreased slightly at heating rate of 450 degrees C/s when final temperature was no lower than 1200 degrees C. Char reactivity measured by TGA analysis was found to correlate with the evolution of char surface area and pore volume with temperature and heating rate. (c) 2015 Elsevier Ltd. All rights reserved.