That depends on a number of things, sharpness being the most important since you won't have control of some of the others like sharpness angle and cutting angle.
Another thing that helps reduce the risk, is to wet the surface right before running it over or through the machines. Wet wood is only about half as hard as dry, so it makes it easier on the knives. However let me warn you to be sure to wax your jointer beds before you try to surface any wet wood. The wetness makes it try to stick so feeding it becomes jerky. That won't be an issue with the thickness planer.