Are burls dry? Are burls dry enough to work? Are they stabilized? These are questions I often hear from customers . . .
Let me tackle the topic of dryness first . . .
While some of the products I offer - like slabs if I've had them stickered for awhile - may be dry for my local climate, I generally recommend customers treat all purchases as green. When I ship orders, I wrap all burls and hardwoods in plastic stretch wrap to protect your purchase in transit. You may want to leave your order wrapped allowing the burl/hardwood to acclimate to your climate, but it is not necessary. Should you do choose to leave them wrapped for an extended period, I recommend you cut a couple/few small slits in the wrap.
The short answer to the question of dryness is NO - they are not dry. The more more accurate answer is NO - they are not dry - and the dryness or moisture content is irrelevant, unless perhaps you are looking to buy today, cut or work and finish tomorrow, and sell the following day.
One can turn or carve something out of a burl and finish it the next day. But it will move as stresses that held it in its original shape are relieved, as moisture content decreases and the burl acclimates to local conditions, and when climatological conditions change from dry to humid or vice versa. Any violinist - like my wife - will tell you that even a 300+ year old Stradivarius will move, as will the kiln dried wood in your home. Eucalyptus burls are no different - the properties of wood and effect of humidity don't cease to exist because they are burls. So the same methods used to dry wood used in your home may be used to dry burls for use.
For some projects - a natural edge vase or power carving come to mind - a bit of movement may not be problematic. I've done both projects from start to finish (without kiln drying in between roughing and finishing). I find that the the inevitable raising of the grain on a power carving from a green burl is less bothersome the lower the sheen on the finish. That said, I will normally allow the rough carved burl to air dry for a lengthy period or dry/stress relieve it in my homemade kiln.
Eucalyptus burls I import may have been harvested as recently as 3-4 months to a year or more prior to taking delivery. They are very dense, so air drying would take forever. But it's not necessary, nor would I recommend waiting the standard 1 year per inch of thickness for a burl to air dry. Why? Because you'll likely have internal cracking. On the other hand, a green burl will work more easily and may be dried in a manner that will preclude cracking and minimize movement.
That is not to say that I do not recommend drying burls. I rough turn everything I make and then dry in a homemade kiln or allow to air dry before finishing. Likewise, customers making knives, gun grips, call blanks pool cues, hybrid castings, etc., will want to make sure the burl is dry before finishing.
When cutting dimensional stock like cue blanks, scales, grips, veneer, movement will occur if they are not restrained in some manner. One can literally watch veneer bend immediately after cutting if not stacked or stickered with sufficient weight applied to restrain movement. I wrap everything I cut in stretch wrap, leaving the ends open or cutting small holes to allow moisture to escape.