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Plot a graph between the age of a tree (in years) on the x-axis and the diameter of the tree (in cm) along with the number of annual rings formed over time on the y-axis, using the data given in the Table 3.7.
| S. No. | Age of the teak tree (Years) | DBH (Diameter at Breast Height) of tree (cm) | Number of annual rings formed |
|---|---|---|---|
| 1. | 5 | 4 | 5 |
| 2. | 10 | 8 | 10 |
| 3. | 20 | 24 | 20 |
| 4. | 25 | 28 | 25 |
| 5. | 30 | 32 | 30 |
| 6. | 40 | 40 | 40 |
![Question 7 — Plot a graph between - Tissues in Action - [Teachoo] - Questions at the end of the chapter](https://cdn.teachoo.com/727426ea-5a30-4a2d-a96c-acf8dc140868/graph-teak-tree-age-vs-diameter-and-annual-rings.webp)
Y-axis: diameter (cm)
and number of rings
Diameter rises
with age
Number of rings
= age of tree
X-axis: age of
tree (years)
10
Age of teak tree (years)
View Answer
| Age of the tree (years) | DBH (cm) | Annual rings formed | What this tells us |
|---|---|---|---|
| 5 | 4 | 5 | Rings = age, right from the start |
| 10 | 8 | 10 | Diameter has doubled in 5 years |
| 20 | 24 | 20 | The fastest growth in girth |
| 25 | 28 | 25 | Growth in girth begins to slow |
| 30 | 32 | 30 | Steady, slower thickening |
| 40 | 40 | 40 | Rings still equal the age exactly |
(i) The graph rises steadily: as the tree gets older, its diameter increases. So the stem keeps growing thicker over time.
(ii) The number of annual rings equals the age in years, and the diameter grows along with it — so more rings mean a thicker, older tree.
(iii) The lateral meristem is responsible for the girth of the stem. It lies in a ring along the stem.
Reading the Teak Tree Graph
Age increases
The diameter increases steadily.
↓
Annual rings
Their number equals the age in years.
↓
More rings and a wider trunk both mean an older tree
