- As weather warms and more daylight in spring from winter, trees begin to grow.
- Cells in ring of Cambium in trunk divide, producing new phloem tissue on the outside of the ring and new xylem tissue on the inside. This process continues throughout summer, but new cells produces later in the year are smaller than the ones during the period of maximum growth in spring.
- Xylem tissue makes the wood of the trunk. The rings in the trunk (when cut) correspond to the growth cycle - tissue made in spring is usually lighter in colour because the vessles are larger, summer xylem…