Canopy throughfall and interception

A detailed study of rainfall passage and capture in the tree canopy


The forest canopy breaks up and captures rainfall, playing an important role in many hydrological, biogeochemical and ecological processes. Over the course of a year Forest Research collected detailed metereological and precipitation data and characterised the canopy at two sites: an oak forest at Alice Holt and a Scots pine forest at Thetford. The team evaluated the suitability of Gash’s model – the most widely used model of canopy interception – to the short timescales required by modern ecosystem process models.

Key findings and outputs

  • Canopy characterisation: high resolution measurements used to determine the interception capabilities (throughfall and stemflow) and canopy characteristics (area indices, aerodynamic conductance and water holding capacity) of both sites
  • Parameters: estimation of the five parameters required to calibrate Gash’s rainfall interception model
  • Evaluation: the model performed well against measured data at the seasonable timescale, but it's performance was less satisfactory for shorter timescales
Example of hemispherical photographs for Oak and Scots pine
Example of hemispherical photographs for Oak (left) and Scots pine (right)


Available on request.

Funders and partners

EU flag

Part-funded by the EU Forest Focus ‘C’ scheme.




For details about the modelling component

Catia Arcangeli

For details of the instrumentation

Matthew Wilkinson