One of the most important indicators of wood quality is its density. Structural and physical properties of wood products, for instance their strength, are strongly related to the density of wood. Nuclear densitometry is one of the most accurate methods for measuring density that is based on attenuation detection of gamma ray flux with a certain activity. There are three main methods for density measurement by gamma rays: transmission, backscatter and reactive methods. In this paper, based on the transmission method, two experimental set-ups were prepared for measuring the density of 10 different kinds of wood within the density range of 0.317–0.819 g/cm3. By optimizing the counting time and source-to-detector distance, density of woods were measured with the accuracy of 0.01 g/cm3. Compared with the commonly used methods that are time-consuming and expensive, the proposed method is simple, rapid, precise, non-destructive, and more reliable.

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