well, i have mostly Black-Walnut and shagbark hickory on this 2.5 acres. the story of picking up the black walnust and hitting the side of a building and leaving marks is exactly right. that stuff is used to stain wood. the old timers dyed rusty traps with it. i poured some brown water on the ground and worms shot out of the ground like missiles from a silo.
once on the ground, the hull turns black, from the inside out, and gets really mushy. the original paintballs, if you didnt mind black hands.
i think the trees make iodine. yea, thats right, make it. so does kelp.