Trees (2006) 20: 219–223 DOI 10.1007/s00468-005-0028-0 ORIGINAL ARTICLE Adzo Dzifa Kokutse · Alexia Stokes · Henri Baill` eres · Kouami Kokou · Christine Baudasse Decay resistance of Togolese teak (Tectona grandis L.f) heartwood and relationship with colour Received: 10 February 2005 / Accepted: 25 August 2005 / Published online: 4 January 2006 C  Springer-Verlag 2006 Abstract Togolese teak (Tectona grandis L.f) is highly resistant to pathogen attack, but variability in natural dura- bility exists between trees of different ages, plantations and geographical zones. Therefore, further information concerning this parameter of wood quality is necessary; however, traditional testing methods are difficult and time- consuming to carry out. We tested the possibility of using colorimetry to determine durability in heartwood samples taken from a wide range of trees. Twelve hundred samples from 31 trees were exposed to four fungi: Pycnoporus sanguineus, Antrodia sp., Gloephy- lum trabeum, and Coriolus versicolor. Wood samples were grouped into three classes (inner, intermediate and outer heartwood). The colour parameters of each sample were then determined using the CIELAB (L ∗ ,a ∗ ,b ∗ ) system and results correlated with the %mass loss of wood after fungal attack. Tests showed that Antrodia sp. and C. versicolor re- sulted in <20% mass loss, whereas all samples were rated as durable or highly durable with regard to P. sanguineus and G. trabeum. Inner heartwood was found to be the most resistant to pathogen attack and outer heartwood the least. Measurements of colour showed that heartwood was lightest nearest the pith and darkness and redness increased towards the outer heartwood. Regressions of lightness with %mass loss in the durability tests were always highly sig- nificant, whereas a ∗ and b ∗ were not always significantly A. D. Kokutse · A. Stokes () Laboratoire de Rh´ eologie des Bois de Bordeaux (Mixed unit: Universit´ e Bordeaux I/ INRA/CNRS), 69 rte d’Arcachon, 33612 Cestas cedex, France e-mail: stokes@lrbb3.pierroton.inra.fr Tel.: +33-5-57122821 Fax: +33-5-56680713 A. D. Kokutse · K. Kokou Laboratoire de Botanique et Ecologie V´ eg´ etale, Facult´ e des Sciences, Universit´ e de Lom´ e, B.P.1515, Togo H. Baill` eres · C. Baudasse CIRAD-Forˆ et, TA 80/03, 34398 Montpellier cedex 5, France regressed with %mass loss. Therefore, the use of colorime- try as a tool to estimate short-term natural durability both rapidly and cheaply could be considered in the case of plantation grown teak wood. Keywords CIELAB . Colorimetry . Natural durability . Wood colour . Wood quality Introduction Teak (Tectona grandis L.f) has long been known to possess highly durable wood, due largely to the presence of extracts in the heartwood, e.g. anthraquinines and tectoquinones (Pahup et al. 1989; Yamamoto et al. 1998; Simatupang and Yamamoto 1999; Haluk et al. 2001). Due to this natu- ral durability, teak is often used for outdoor purposes, e.g. boat decks, bridge building, and garden furniture, as well as traditional indoor uses, e.g. flooring and furnishings. Such uses require a highly stable wood with regard to physical properties, as well as an aesthetically pleasing colour and adequate resistance to pathogens. Therefore, further infor- mation concerning the natural durability of teak wood is indispensable, if such knowledge is to be used in breeding programs, or the wood used to its best advantage by the end-user. In order to determine the natural durability of a wood sample, tests can be carried out using different types of fungi (AFNOR 1994, 1996). However, these tests are diffi- cult to perform for the end-user, as certain laboratory con- ditions are required. Each test also takes several weeks to complete. Therefore, a more rapid method for testing dura- bility would be extremely useful. Such a method would be even more valuable if it was portable enough to be used in the field, or could be moved from laboratory to sawmill. Large scale testing of wood from different provenances, plantations or regions could then be carried out. Natural durability is a factor that varies enormously in any given species, not only between trees, but also within the same tree (Baill` eres and Durand 2000). It is therefore difficult to state with any certainty how durable a wood