Shigeki Murakami, Tae Toba
Released: November 21, 2013

Experimental study on canopy interception using artificial Christmas trees to evaluate evaporation during rainfall and the effects of tree height and thinning

Shigeki Murakami1), Tae Toba2)

1) Tohkamachi Experimental Station, Forestry and Forest Products Research Institute
2) Department of Life Environment Studies, Shokei Gakuin University

Canopy interception (I) was measured using artificial Christmas trees that were set on three trays under natural rainfall. Tree heights were 65 cm, 110 cm and 240 cm, with two of the higher stands thinned after three months. Gross rainfall (PG) and water storage on a single tree of 65 cm high and 240 cm were measured, which enabled calculation of I not only on a per rain event basis but also over shorter time periods. Canopy interception rate (I/PG) was comparable with that in the actual forest. The value of I/PG tended to increase with tree height, while it increased or decreased after thinning depending on the forest structure. Evaporation during rainfall (IR), during storm break time (ISbt) and after the cessation of rainfall (IAft) was calculated on a sub rain event basis at a resolution of 5 minutes. A sub rain event was defined when rainfall broke for more than 20 minutes during the rain event. Among the three evaporation components, IR constituted nearly all of the total I, with ISbt close to zero and only a small contribution from IAft. The model forest appears useful for studying the mechanisms of I that are unexplainable using conventional approaches.

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