Canopy interception is the

rainfall Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...

that is intercepted by the

canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an a ...

of a tree and successively evaporates from the leaves.

Precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

that is not intercepted will fall as

throughfall In Hydrology, throughfall is the process which describes how wet leaves shed excess water onto the ground surface. These drops have greater erosive power because they are heavier than rain drops. Furthermore, where there is a high canopy, falling ...

stemflow In hydrology, stemflow is the flow of intercepted water down the trunk or stem of a plant. Stemflow, along with throughfall, is responsible for the transferral of precipitation and nutrients from the canopy to the soil. In tropical rainforests, w ...

on the forest floor. Many methods exist to measure canopy interception. The most often used method is by measuring rainfall above the canopy and subtract throughfall and stem flow (e.g., Helvey and Patric 965. However, the problem with this method is that the canopy is not homogeneous, which causes difficulty in obtaining representative throughfall data. Another method that tried to avoid this problem is applied by e.g., Shuttleworth et al.

984 Year 984 ( CMLXXXIV) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar. Events By place Europe * Spring – German boy-king Otto III (4-years old) is seized by the deposed Henry II ( ...

Calder et al.

986 Year 986 (Roman numerals, CMLXXXVI) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. Events By place Byzantine Empire * August 17 – Battle of the Gates of Trajan: Emperor Basil ...

and Calder 990 They covered the forest floor with plastic sheets and collected the throughfall. The disadvantage of this method is that it is not suitable for long periods, because in the end the trees will dry due to

water shortage Water scarcity (closely related to water stress or water crisis) is the lack of fresh water resources to meet the standard water demand. There are two types of water scarcity: physical or economic water scarcity. Physical water scarcity is where ...

, and the method is also not applicable for snow events. The method by Hancock and Crowther

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avoided these problems by making use of the cantilever effect of branches. If leaves on a branch hold water, it becomes more heavy and will bend. By measuring the displacement, it is possible to determine the amount intercepted water. Huang et al.Huang, Y. S., Chen, S. S., Lin, T. P., 2005. Continuous monitoring of water loading of trees and canopy rainfall interception using the strain gauge method. Journal of Hydrology 311, 1–7. refined this method later in 2005 by making use of strain gauges. However, the disadvantages of these methods are that only information about one single branch is obtained and it will be quite laborious to measure an entire tree or forest.

References

Hydrology Forest ecology {{forestry-stub

See also

References