how to detect the nearest block of a specific type in a certain radius

I'm trying to make a simple NPC that you can find around breaking trees, but the "Break block" task makes the NPC jump on the block (like a zombie on turtle eggs) to break it. My solution would be to make a procedure that activates on spawn with a while loop that checks if there is a wood block near it and if not go in a random direction, but I don't think there's any way to find the nearest block of a type. Is there some workaround I could use that would allow me to make this NPC?