Answer:
Though not a plant I have leaves. though not a beast I have spine. Though many wouldn't need me I am more valuable than wine.
People need me yet they give me away every day.
What force and strength cannot get through I with my unique teeth can do.
After you go through a fall, I will take over. All life will stall, or at least grow slower. What am I?
I am used when you jump off a bridge for fun.
you hold my tail while I fish for you