Interception Loss of Tree Canopy as Green Infrastructure

Abstract

This chapter discussed the role of trees in the environment and hence on the hydrological cycle. There are many processes involved in the hydrological cycle, namely precipitation, evaporation, infiltration, canopy interception and transpiration. The trees acted as land cover influences the hydrological cycle, including the trees’ capacity to intercept, evapotranspiration, purify, store, and infiltrate the rainfall. The interception process in the hydrological cycle can be up to 30–50% of the total gross precipitation. The structure of the canopy forest reduces the amount of runoff which the trees intercept the precipitation and use the water during the interception process. This process thus decreasing the volume of water draining through a catchment area. In this chapter, the amount of interception loss in tropical forests was determined. The interception loss was determined by quantifying the difference between gross rainfall and net rainfall (throughfall and stemflow). Original Gash model was also applied to computed the interception loss value. Two plots were chosen as study area namely Plot 11 and Plot 12. In the direct measurements, interception loss for Plot 11 is 13.6% of the gross rainfall and for Plot 12 produced 10.8% of the gross rainfall for the 12-month periods. Whereas, from the Gash model computation, interception loss from Plot11 produced 14.7% and while for Plot 12, the original contributed 13.6% of the total gross rainfall during the study period.