In root crops such as carrots and parsnips, the active root growth bud is at the apex of the root. This bud is easily damaged by such things as a sharp stone, pockets of acid (recent manure or compost), or by attack from soil pests, and when this occurs the bud dies and a new dormant bud close to the crown starts into growth. This is what causes `forking`. In very stony soil, or where there is recent manure it is not uncommon to see carrots with 4 or 5 roots.