<p>The growth of trees is shaped by the complex interplay of various processes. Among key players is the vascular cambium, a meristematic tissue found within tree trunks and branches, responsible for growth in girth. In this article, we explore relationship between the vascular cambium, tree trunk circumference, periclinal and anticlinal cell divisions, wood fibres, and a circular symmetry exhibited by woody plant stems– manifesting as annual growth rings deposited each year in temperate, and other strongly seasonal regions, but also wood tissue continuously deposited in tropical rainforests. Using anatomical-developmental exploration and mathematical calculations, we aim to uncover how process of cambial derivatives development is enabled as the vascular cambium moves away from stem pith due to cell divisions of initials and xylem mother cells. We found that special developmental characteristics of rays enable growth of wood fibres deposited inwards by the vascular cambium, which is associated with widening of a sector of axial system cells located between two rays in the differentiation zone. We show that due to dynamic changes occurring within rays, it is possible for wood fibres to grow without disrupting the circular symmetry of the tree trunk. This sheds some light on their influence on plant growth and secondary xylem formation. By understanding this dynamic interplay, valuable insights into the biology and growth dynamics of woody plants can be gained, which may contribute to optimizing the production and quality of wood and wood-based materials.</p>