If you want a detailed answer, it is about 1.5-2x as high parallel to the grain as perpendicular to the grain and increases with moisture. Generally, in a natural form it is in the range of 0.1-0.15 W/m K perpendicular to the grain. It is much lower (0.05 or so W/m K) if it is kiln dried. 

given the diversity of eucalyptus species (about 600 species, grown from tropical environments to semi-arid ones), with very variable growth rates and wood structures, the values above from Larry Baxter are as precise as one is going to get. If you have know the species you are interested, it might be possible to find some more precisse values.