The Three Orders of Buoyant Wood, also known as The Three Orders of Deepwoods Timber were a way of classifying all the trees of the Edge.
The Third Order
Trees of this order maintained a stable buoyancy at any temperature.
The Second Order
These woods became buoyant when they were burnt.
- Bloodoak - The most buoyant, and rare, second order wood. It screamed and wailed as it burnt
- Lufwood - Gave off purple flames when burning
- Lullabee - "Sang" a mournful song, not to everyone's taste, as it burnt
The First Order
First order woods were extremely rare throughout the Deepwoods. According to Tweezel, this is "the most interesting order." Woods from this order are buoyant at any temperature, but slightest changes in humidity or temperature can destabilise it. This meant these woods' only practical uses were for floating furniture, indoors.
- Sumpwood (The most common, and stable, first order wood)
In 60 ᴇ.ʏ. Tweezel invented a special varnish that sealed in the buoyant properties of the wood, while still allowing it to "breathe". This meant the wood could remain stable in all but the most extreme of temperatures.