did they also look different when they were sinking? I am asking so to understand if it is the resin that was more spread out and then concentrated into specific spots leaving more wood fiber exposed to allow float. like a body that will float with floats and sink without them. of course i dont know how resin reacts to time within the wood fibers when fresh. i dont know if the resin doesnt change place or if it does in time as the wood cures. this happens to many plants. if this is not the case then it could be just that they had more hydrosol within when they were extracted from the bark and in time it evaporated.