Energy characteristics of wood and charcoal of selected tree species in Mexico

This study determines the main energy characteristics of wood and charcoal within five tree species of the forest of Ixtlán de Juárez, Oaxaca, México: Alnus acuminata, Arbutus xalapensis, Myrsine juergensenii, Persea longipes and Prunus serotina. Basic density, moisture content, charcoal yield, volatile material, ash content, high heating value, fixed carbon and fuel value index were determined for each one. The average results of the species are in the range of 0.372 to 0.498 g. cm-3 for wood density; 26.19 to 34.12% for charcoal yield; 77.29 to 83.66% for wood volatile matter and 28.40 to 34.25% for charcoal volatile matter; 0.56 to 1.50% for wood ash and 1.13 to 4.83% for charcoal; 19.50 to 24.99 MJ. kg-1 for high heating value of wood and 29.38 to 32.11 MJ. kg-1 for charcoal. It was determined that these species provide a good alternative for burning wood and charcoal. Additionally, these remain untapped resources in the Sierra Juárez region, meaning that awareness and inclusion in management plans could be of relative importance to the development of the forestry sector.

Development and validation of an analytical method for condensed tannin extracts obtained from the bark of four tree species using HPLC

Herein, we evaluated the content of condensed tannins present in the bark of four tree species that are Quercus laurina Humb. & Bonpl., Quercus crassifolia Humb. & Bonpl., Arbutus xalapensis Kunth, and Prunus serotina Ehrn. An analytical method using high-performance liquid chromatography (HPLC) for condensed tannin extracts was developed and validated. Also, the aqueous extracts were analyzed by Fourier transform infrared spectroscopy (FTIR). Based on the Stiasny number, A. xalapensis, and Q. laurina represent an important source of condensed tannins, which may be subject to exploitation. Using infrared spectroscopy, it was observed that tannins do not show an important signal of carbonyl groups (aromatic esters) with respect to high purity catechin. Furthermore, the band of the hydroxyl group is less pronounced in tannins, because various hydroxyl are interacting with each other. However, it can be seen that the method of extraction of wood tannins developed in this work, presents satisfactory results.