Question

Age of a tree can be estimated by:

• A. diameter of its heartwood
• B. its height and girth
• C. biomass
• D. number of annual rings

Answer 1

The Correct Option is D

Age of tree can be estimated by the number of annual rings. Every year, a new layer of wood is added to the trunk and the branches of the tree and these layers forms the annual rings. Thus, one annual ring is equal to one year. The new layer is formed from the cambium between the bark and the old wood. 

There are two distinct portions in an annual ring:

• Light Portion - This portion is called ‘Springwood’. The growth of this portion takes place in springs. This part is wider than the other part because in spring there is enough moisture to support the growth of the cells. 
• Dark Portion - This region is called ‘Summerwood’. This part is comparatively thinner as in summer the growth slows down and finally stops at a time. 

The two kinds of woods that appear as alternate concentric rings, constitute an annual ring heartwood having dead elements with highly lignified walls that provides mechanical support to the stem. The height and girth of a tree increases due to the activity of vascular cambium.