Can anyone tell me what causes girdle scars on twigs? Someone told me they're the remnants of the previous year's apical bud and you can therefore tell the age of a twig by the number of scars. Is this true? If so why don't other buds leave similar scars? What is unique about apical buds that makes them leave these distinct girdle buds? Thank you to anyone who can help!
Trees form buds for three basic purposes: shoot growth, leaf production, and flower production. Sometimes all three types are contained in the same bud. The terminal bud and lateral buds form branches, so a ring scar is left where the annual growth begins. (I believe most trees form buds during/after the current growth season for the growth that occurs the following year. I am not a tree expert, so there may very well be trees, perhaps tropical, that form buds more than once per season. I hope someone who knows more will chime in here.) The leaf buds and flower buds that are formed on the side of the twigs would not leave the ring scar typical of the terminal or lateral buds. You have seen examples of this type of scar. It is easy to recognize on house plants that have lost leaves. Bud scars vary on trees and plants, some will be large, others almost nonexistent. Here is a link to a clear and simple explanation of how trees grow. http://www.forestry.iastate.edu/publications/pubs-pdf/F-308.pdf [PDF 354kb]
