Interception Introduction

2.1 What is the interception?

                Interception is natural or artificial covers intercept of falling water droplets toward to ground. These water droplets store on the surface of the tress, after fails to the ground or evaporate back to the atmosphere.   

               2.2 Components of interception

(1)Interception loss (I)

       Water retained in the surface and evaporates or absorb by the plants later.

(2) Throughfall(TF)

                       Water falls through spaces in the vegetation canopy or falls along the twigs and leaves.

(3) Streamflow (SF)

                       Water flows along with the leaves and twigs. Finally, all of the water flows are collected together and fall along the trunk to the surface.

           Interception loss

                I=P-(TF-SF)

2.3Factors affecting interception

(1) Storm (Nature and distribution of the storm.)

Drizzle-Before reaching to the ground, most of the water droplets are evaporated. When intensity and duration of precipitation are relatively high, lower interception is taken place.

(2)A plant (Canopy size, canopy density and leaf characteristics)

When canopy size is wide, more water droplets are intercepted, they took relatively more time to reach the ground so most of the water droplets are evaporated back to the atmosphere. When canopy density is high, amount of leaves and twigs in unit surface area is relatively high so more water droplets are intercepted and take relatively more time to reach the ground, therefore, most of the water droplets are evaporated during the process. When leaves are rough, they consist of less amount of wax, therefore, water droplets are relatively more tended to remain on the surface so most of the water droplets are intercepted and evaporated back to atmosphere. When leaves are smooth that means these leaves consists of relatively more wax so water droplets are relatively less tented to remain on the surface of the leaves, therefore, interception is limited and evaporation back to the atmosphere is relatively less.

(3) Season of the year (Vegetative growth and canopy characters)

Rainfall is relatively more intercepted than snowfall. Some of the trees are removed them all leaves in specific duration in each year and grow new leaves after duration. Therefore interception is relatively most limited during that time period and most of the water droplets are reached to ground. Less evaporation has occurred.

(4) Prevailing wind

Interception of leaves and twigs are reduced by prevailing wind but the evaporation rate is relatively high.