Hey there! I'm sorry you're experiencing trouble with this It's a random chance you will or will not get a particular resource each time you harvest from an item, so even if there's a high chance of something dropping there's always a chance it won't (excluding items with guaranteed drops). The item which will for sure always drop Living Wood is the Living Tree. The next-highest chance of a Living Wood drop is from the Bidding Booth, followed by the Magic Garden. I hope that helps!
I don't seem to be dropping any living wood when cutting down trees and need these to level up a building, why is this happening