inner bark

Inner bark is the living layer of a tree's bark, located between the outer protective bark and the wood.

Also called phloem or bast, it transports sugars and nutrients produced by photosynthesis throughout the tree.

This layer has historically been important for human survival, as many cultures have harvested inner bark from certain species for food, medicine, or fiber for cordage and textiles.

The inner bark of birch trees was traditionally used to make containers.