Question

In our country diameter or girth at breast height is measured at _________.

• A. 1.37 m
• B. 1.30 m
• C. 1.31 m
• D. 1.27 m

Hint:

Measuring at the standard DBH of $1.37 \text{ m}$ is also convenient for field researchers, as it is roughly at chest height for an average-sized adult, making caliper or DBH tape measurements comfortable to perform.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Diameter at Breast Height (DBH) or Girth at Breast Height (GBH) is the standard reference height used by foresters to measure tree diameter.
Using a standard height avoids irregularities caused by basal buttressing and ensures measurements are consistent and comparable.

Step 2: Detailed Explanation:
While different countries have adopted slightly different standard heights for DBH measurements, in India, the standard reference height is officially established at $1.37 \text{ meters}$ (or $4.5 \text{ feet}$) above the ground level.
For trees growing on slopes, DBH is measured on the uphill side of the tree.
For leaning trees, DBH is measured along the lean of the tree stem rather than vertically from the ground.
Let us compare this with other regional standards:
- $1.30 \text{ meters}$ is the standard DBH height in Europe, the United Kingdom, and many international forestry protocols.
- $1.40 \text{ meters}$ is used in some other commonwealth nations.
In Indian forestry practice and forest inventories managed by the Forest Survey of India (FSI), $1.37 \text{ m}$ remains the standard height.

Step 3: Final Answer:
The standard height for diameter or girth at breast height in India is $1.37 \text{ m}$, corresponding to option (A).