Arguably the knottiest problem of wood sculpture is to season logs with minimal checking. Checks are the cracks that open up as green wood dries. They appear as air wicks moisture from the ends and outer layers. As they dry they shrink, while the slower-drying core remains stable, and cracks necessarily open.
This problem of differential shrinking may be greatly alleviated by harvesting wood in the early winter, after the sap has drained into the roots and before its spring rising. Or, if a tree must be taken down in the growing season, don’t immediately saw it up, but let it wilt. A good bit of moisture will transpire through the leaves on hot summer days. When they are brown and dry, the wood will have seasoned appreciably, with minimal checking.
Once the wood is cut into logs, the rapid drying that causes checking may be slowed by applying paint, stain, linseed oil or even wax to the ends, Leave the bark on. Treating it with linseed oil will both slow the drying and discourage insects.
To hasten drying of the core, one may bore a hole up the center of the log. Here a bit extension is helpful. Store the log under cover and off the ground so that air may circulate freely over all surfaces.
Even wood which has seasoned for years will check in carving. The carver may alleviate this by treating the piece with linseed oil and wrapping it in plastic after each session.
The sculptor may also seek out woods which are not prone to checking. Of these willow, while not otherwise great carving wood, excels. Elm, with its interwoven grain, resists checking as does butternut. Both make great carving wood.