cambium [ KAM-bee-uhm ] noun: a formative cylindrical layer of tissue found between the bark and the wood that divides to form new wood and bark
Vascular cambium, a cylindrical layer one to several cells thick, lies between the phloem and xylem of roots and stems in most vascular plants. It gives rise to new cells and is responsible for secondary growth that increases the plant’s girth—adds phloem outward and xylem inward. Cork cambium is a cylindrical layer in the periderm of woody plants. In new growth it lies between the epidermis and phloem and as the plant matures, replaces the epidermis with outer bark. Cork cambium produces cork outward and phelloderm inward.
How a Tree Grows. University of New Hampshire Extension. (accessed April 11, 2023).
Wilkin D, Brainard J. 2012, modified 2021. Plant Growth. CK-12 Foundation.