We need a language to read a book, and that affects our thought process, as we start thinking like the author and behave in a manner we perceive from the books. Like how someone speaks under the influence of alcohol, books n authors too influence.
Sawdust that is created from cutting natural wood is safe for your compost no matter what kind of tree the wood comes from. Just make sure the wood has not been treated with any chemicals. Another option with sawdust is to try mixing it in with potting soil.
When sanding a large piece of the same type of wood, clean out your sawdust catch on your random orbit sander before starting. Do all of the wood of the same type, dump it into some container with a lid or a zip-lock, label it with the type of wood, and use it later for filler.