Kiln drying behavior of lumber from ten fast-growth plantation species in Costa Rica

Abstract

Plantation wood from tropical climate has been introduced rapidly in the national market; however, there is lack of knowledge about the process. The main objective of this study was to investigate the kiln drying behavior of 10 plantation-grown wood species from natural forest in Costa Rica using the recommended drying schedule. Initial moisture content (MCi), final moisture content (MCf), drying rate, drying time, and drying defects were evaluated. The drying schedule applied produced the following results: (1) high MCi (over 110%) in four species and lower values in two species. (2) The largest drying time was found in species with high MCi, and the shortest drying time in species with lower MCi. (3) Significant variations of target MCf were found in some species, despite equalization and conditioning. (4) Exponential relationship MC=a*ϵ^−t*b was used to establish a moisture content (MC) decrease model, which is not a good indicator of drying time for fives species. (5) High incidence of drying defects was found in Alnus acuminata and Vochysia guatemalensis. According to the above results, it is necessary to test other drying schedule oriented to improve lumber quality and to decrease variability of MC in wood from plantation trees.

Keywords:

• Dried lumber
• kiln drying
• moisture content
• tropical species
• wood quality

Acknowledgements

The authors wish to thank the Vicerrectoría de Investigación y Extensión at the Instituto Tecnológico de Costa Rica (ITCR), and Precious Woods of Central America (MACORI), Maderas Cultivadas de Costa Rica, Escuela de Agricultura de Trópico Húmedo (EARTH), and Finca Junquijal for the raw materials and facilities for the study.