Alternatively:
log + axe = wood chips and branches (+ knife = arrows, making this a twofer)
pixie dust + paper or parchment (or notes* that you've found) = random type of blank scroll
*just don't use anything you may need as evidence later.
You can get one guaranteed earth essence in the N corner of the map.
Also:
blank scroll + blank scroll (same type) = blank spellbook of that type
blank spellbook + scroll (same type) = spellbook for that skill
So if you're having a hard time finding spellbooks, and blank srolls aren't dropping out of the skies into the vendor's stock, you can forage for materials to make them.
