Question

Age of a tree may be ascertained by

• A. Radius of its stem
• B. Circumference of its stem
• C. Number of branches
• D. Number of annual rings

Hint:

Tree rings provide valuable information beyond just age. They can also reveal past climatic conditions, such as droughts, floods, and temperature changes, by analyzing the width and density of the rings.

Answer 1

The Correct Option is D

Step 1: Understand the process of tree aging.
The age of a tree is typically determined by studying its growth patterns, which are recorded within its trunk.
Step 2: Identify the primary method for age determination.
The most reliable and common method to ascertain the age of a tree is by counting its annual rings (also known as growth rings or tree rings). Each ring generally represents one year of growth, with a wider ring indicating a good growing season and a narrower ring indicating a poorer one. This field of study is called dendrochronology.
Step 3: Evaluate the given options.
Option 1: Radius of its stem. While the radius is related to the tree's growth, it doesn't directly indicate age without knowing the growth rate, which can vary significantly.
Option 2: Circumference of its stem. Similar to the radius, circumference is a measure of size, not a direct indicator of age. Two trees of the same circumference can have very different ages depending on their species and growing conditions.
Option 3: Number of branches. The number of branches is not a consistent indicator of a tree's age. Branching patterns can be influenced by many factors, including species, environment, and pruning.
Option 4: Number of annual rings. This is the accurate method. Each annual ring represents one year of the tree's life, and counting them provides a direct measure of its age.
The final answer is $\boxed{\text{4}}$.