Pros and Cons: Green Wood Vs. Dried Wood
We frequently have people ask us: "What is the best wood to use, green or kiln dried?"
The answer is...it depends. Let's take a look at the ups and downs for each type, and help you determine what you will need for your next project.
Green wood is less expensive than kiln dried wood. Since the lumber must be handled fewer times, there is no loss (dimensionally or due to drying defects), and there are no energy costs involved in drying, the wood can be sold at a more affordable price. The one downside...green wood weighs much more than kiln dried wood, so shipping costs become more expensive.
Air dried wood which is a darker color will retain deeper, more vibrant colors than kiln dried stock. For lightly colored woods, however, staining can occur during storage. Maple, birch, hackberry, beech, pecan, sycamore, holly and a few other common woods can discolor slightly or develop some spalting. While sometimes this staining can create appealing patterns, at other times it does not.
Green wood greatly increases the variety of woods from which you can choose. Nearly any wood can be cut and sealed in paraffin wax without defects occurring during storage. Thicknesses are limited only by the size of the trees from which the lumber is cut.
Green wood turns much more easily than kiln dried wood. Green wood cuts very well, sending off large shavings and relatively little sawdust. The moisture within the wood also lubricates the turning tool, keeping it cool and easy to handle.
There are always some risks involved when drying green wood. Sometimes defects such as cracks and checking can occur. At other times, warping can be quite excessive. If a project requires precise dimensioning (such as in furniture making) then green wood is not recommended for use.
Kiln Dried Wood:
Kiln dried wood is more expensive than green wood. The lumber must be stacked and stickered until it is ready to be loaded in the kiln, then loaded in the kiln at the appropriate time, dried, and unloaded from the kiln. Wood shrinks in volume by at least 5%-6% (often greater), depending upon species during drying. Defects also occur during drying. All of these factors combine and influence the final price which must be paid for kiln dried lumber. The one upside...kiln dried wood weighs significantly less than green wood, and costs much less to ship.
Darkly colored woods tend to lose a bit of their color when kiln dried. Lightly colored woods, on the other hand, tend to hold their color much better when kiln dried. Maple, birch, hackberry, beech, pecan, sycamore, holly, and other lightly colored woods all maintain a much more consistent, even color, which is often preferred with these types of woods.
Kiln dried woods are less available than green woods. Some species are so uncommon that there is not enough available for creating a full load for drying within a kiln. Most often, though, what limits the availability of kiln dried wood is the problems which occur during drying. Most species will dry readily at 2" thick, with minimal problems. 3" thick material, however, can be somewhat problematic to dry for many species. 4" thick material is even more difficult to accomplish, and only a very few types of wood can be successfully dried at this thickness. Material beyond 4" thick is nearly impossible to dry in most species without severe defects showing up during the drying process. This greatly limits the types of wood which can be found, and the thicknesses in which they can be found.
Dried wood is somewhat more difficult to turn than green wood. Turning creates a large amount of sawdust, and far fewer shavings. Tools can become heated from the friction between the wood and the tool, making turning somewhat more uncomfortable for unprotected hands in some cases. Tools will require more frequent sharpening with kiln dried woods as well.
Kiln drying takes the majority of the risks out of turning. Since the wood has already been dried, the user won't have to worry about defects occurring after the wood has been turned. A piece can be turned in one session, with no waiting period since the wood doesn't need to be dried further. Kiln dried wood is excellent for persons who need to do more precise dimensional work, for persons who do not wish to learn how to properly dry wood, and for persons who need to finish a project quickly and efficiently.
We hope that this has been helpful in educating you towards making the best decisions for the type of wood which you will need for your future projects! Just keep in mind...if a wood is rare, will look best with deeper colors in darkly colored woods, or needs to be available in thicknesses beyond perhaps 3", then green wood is likely the best choice. If dimension stability, reduced risks in losses due to defects, more cleanly colored lightly toned woods, or the time to complete a project are the most important factors, then kiln dried woods are the best choice.