This thesis, which is performed as an experiment, deals with dependence of locations on the amount of extractive substances in the heartwood, sapwood and bark of acacia (Robinia pseudoacacia L.) across radius of the trunk. Thesis also aims to determine at what part of the trunk is situated most of extractive substances. Furthermore is evaluated, if the amount of extractive substances is depending on the height of the trunk, at altitudes from 0 m and 1.3 m from which the samples were taken. A final point is to compar according to the cardinal directions. In the theoretical part is described the issue of extractive substances and chemical composition of acacia. The second part presents the measured values from taked and extracted samples and their statistical evaluation.