Why is it that if you cut a tree branch at the trunk The whims stops growing The whims stops growing but grass cut at the ground level grows back?

When a tree branch is cut at the trunk, the removal disrupts the tree's vascular system, which limits its ability to transport nutrients and water to that branch, causing it to stop growing. In contrast, grass has a different growth structure; it grows from the base and has a robust root system that allows it to regenerate even after being cut at ground level. This resilience is due to grass's ability to rapidly produce new shoots from its meristematic tissue, which is located near the soil surface.