The pyrolytic behavior of Pinus halepensis needles observed by transmission light microscopy and stereoscopy

Two microscopic techniques were used for monitoring the changes that occur during the pyrolysis of Pinus halepensis needles at 100, 200, 250, 300, 350 , 400 and 500 degrees C. The changes were monitored by transmission light m icroscopy (LM) and stereoscopy. The following were observed with increasing temperature: (1) deformation of the transverse section; (2) loss of the cu ticle layer and cracking of the outer layer; (3) degradation of lignin (a b asic component of pine needles, and (4) tar and char formation on the exter nal surface. These changes were attributed to chemical and physical phenome na during the pyrolysis procedure. (C) 2000 Elsevier Science B.V. All right s reserved.