**Abstract**

Much of the built heritage is built of wooden structures. Due to the lack of maintenance, it is susceptible to biological attacks, such as fungi and wood destroying insects. Most of the methods used for its inspection and evaluation are intrusive. More friendly methods are required. Infrared thermography, being a non-destructive, contactless and versatile technique, can be a very useful tool in this field. However, the correct temperature measurement depends greatly on the emissivity value of the material. In this chapter, the emissivity values are presented and discussed for wood samples of *Pinus pinaster* species. In a qualitative analysis, this factor is not so important. Moreover, in a quantitative analysis for which the measured temperature value is relevant, it is crucial to know the emissivity value.

**Keywords:** emissivity, infrared thermography (IRT), wood, assessment of wooden heritage structures, heritage conservation, non-destructive testing, quantitative analysis, sustainability
