Question

The portion of rain fall that hits the ground through canopy is called

• A. Interception loss
• B. Throughfall
• C. Interception gain
• D. Stem flow

Hint:

• Interception: Rainfall caught by vegetation surfaces.
• Throughfall: Rainfall that passes directly through the canopy or drips from it to the ground.
• Stemflow: Rainfall that flows down plant stems/trunks to the ground.
• Interception Loss: Intercepted water that evaporates before reaching the ground.
• Effective precipitation reaching the ground under a canopy = Throughfall + Stemflow.

Answer 1

The Correct Option is B

When precipitation (rain, snow) occurs over a vegetated area, it interacts with the plant canopy before potentially reaching the ground. Several processes are involved:

• Interception: Some precipitation is caught and retained on the surfaces of leaves, branches, and stems of vegetation. This intercepted water may later evaporate back into the atmosphere or be absorbed by the plant.
• Throughfall (option b): This is the portion of precipitation that passes directly through openings in the canopy or drips from the leaves and branches to reach the ground surface beneath the canopy.
• Stemflow (option d): This is the portion of precipitation that is intercepted by the canopy and then flows down the stems and trunks of the plants to reach the ground.
• Interception Loss (option a): This is the amount of precipitation that is intercepted by the canopy and subsequently evaporates back into the atmosphere without reaching the ground. It is essentially Precipitation - (Throughfall + Stemflow).
• Interception Gain (option c): This term is not standard in this context. Sometimes, fog drip can lead to a net gain of water under a canopy compared to open areas, but "interception gain" is not a typical term for a component of rainfall partitioning.

The question asks for the portion of rainfall that hits the ground through the canopy. This is precisely the definition of throughfall. \[ \boxed{\text{Throughfall}} \]