Low-Acid Wood Species?
All wood and sawdust tends to be acidic, but some varieties are milder than others. August 1, 2011
A customer is doing artwork and wants us to run picture frame molding and other parts from a wood that is non-acidic or low acid, so it will not react with the low acid papers that are being used.
(Sawing and Drying Forum)
From contributor S:
I just finished making a frame for an artist. The chaps who frame for the AGO here in Toronto specified basswood. They did not mention acid, but I trust their judgment. These folks are the top of the food chain here.
From contributor D:
Over the years, we at Nyle have tested the condensate from drying a lot of species because we need to know the contents of the emissions for air and water. The obvious ones to stay away from are things like oak, cedar, hemlock, etc. But maple, poplar, pine and basswood are pretty mild based on the acid tests we have run. Most wood is acidic though.
From Professor Gene Wengert, forum technical advisor:
Contributor D is correct that wood is naturally acidic. As such, it is not a good choice for items that will be damaged by an acidic environment. There is a book titled "Wood and Cellulose Science" by Stamm that I believe has some info on the pH of wood.