With respect to your question, is alder wood "safe" to use in a kitchen cabinet -- meaning is it nontoxic -- the answer is yes.
To insure low toxicity from the veneer, you will want to specify to the cabinet maker that they:
- use a plywood backing that has no added urea-formaldehyde; and
- you will also want to specify that the glues they use to fabricate the cabinets be free of formaldehyde.
A few items of note with regard to using alder for kitchen cabinetry:
- Stock alder, what would be typically used for the stiles and rails of the cabinet door, is less expensive than stock maple or cherry. However, alder veneer on plywood is typically more expensive than maple ply -- why this is so, I honestly can't tell you. It is common to use the alder veneer on the recessed panel of the cabinet door.
- Alder is often referred to as "the poor man's cherry." An unfair title, in my opinion, because I like the look of alder. However, this may be justified by the fact that alder actually lightens in color with age, unlike most woods that darken and build more "character." So if you are looking for a true amber color tone, consider adding an amber tint to the finish or an amber stain under the finish (clear top coat).
- Additionally, alder is a softer wood than cherry and will dent more easily from long fingernails grabbing cabinet knobs or dishes/pots being roughly removed from/returned to cabinetry.
- Remember to specify whether you want knotty alder (for a rustic look) or clear alder for a more contemporary look (will likely be more expensive).
For more information:
Read Cynthia Phakos's Q&A "Can you recommend affordable green kitchen cabinets, flooring, and countertops?"
Also, be sure to read George Mandala's "Getting Great Green Results from a Cabinet Shop."