Secondary growth of a plant begins after primary growth and it leads to the formation of woody axis.
Secondary growth takes place due to the activity of secondary meristems such as vascular cambium and cork cambium.
The fusion of intra-fascicular cambium and inter-fascicular cambium results in the formation of the cambial ring.
Cambium activity which takes place in spring results in spring wood and cambium activity in autumn results in autumn wood.
Spring and autumn wood appear as alternate concentric rings and form annual rings.
The tissue outside the vascular cambium, which includes the secondary phloem, is known as bark.
Secondary growth of stems and roots occurs mainly in dicots and gymnosperms, while monocots lack secondary growth.