Question

Which slope gradients are best suited for forest growth ?

• A. 5 to 10$^\circ$
• B. 11 to 20$^\circ$
• C. 21 to 30$^\circ$
• D. 31 to 45$^\circ$

Hint:

Forest Site Quality & Topography:
Gentle slopes ($5--10^\circ$) provide deep soil + excellent draige + minimal soil erosion = Maximum site quality for silviculture.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the optimal slope angle (gradient in degrees) that provides the best conditions for tree development and forest growth.

Step 2: Topographic Factors in Forestry:

• Gentle Slopes ($5--10^\circ$): Allow maximum rainwater infiltration, maintain high subsoil moisture retention, accumulate deep fertile topsoil layers, and minimize surface run-off erosion.

• Moderate Slopes ($11--20^\circ$): Increased run-off velocity, moderate soil erosion potential.

• Steep Slopes ($>20^\circ$): Rapid soil loss, shallow skeletal soils, difficulty in root anchorage, and high susceptibility to landslides.

Step 3: Detailed Explation:

• Trees achieve maximum stem height and site index on gentle slopes ($5--10^\circ$) due to superior soil depth, organic matter accumulation, and water availability.

• Extremely flat ground ($0--2^\circ$) may suffer from waterlogging or poor draige depending on clay content, whereas steep slopes ($>30^\circ$) lack deep soil horizons required for root growth.

• Therefore, a gentle gradient of $5--10^\circ$ represents the optimal range for healthy silvicultural productivity.

Step 4: Fil Answer:
Slope gradients of $5$ to $10^\circ$ are best suited for forest growth. Thus, option (A) is correct.