Canopy conductance, commonly denoted
, is a
dimensionless quantity
A dimensionless quantity (also known as a bare quantity, pure quantity, or scalar quantity as well as quantity of dimension one) is a quantity to which no physical dimension is assigned, with a corresponding SI unit of measurement of one (or 1) ...
characterizing radiation distribution in tree
canopy. By definition, it is calculated as a ratio of daily water use to daily mean
vapor pressure deficit
Vapour-pressure deficit, or VPD, is the difference (deficit) between the amount of moisture in the air and how much moisture the air can hold when it is saturated. Once air becomes saturated, water will condense out to form clouds, dew or films o ...
(VPD). Canopy conductance can be also experimentally obtained by measuring sap flow and environmental variables.
Stomatal conductance Stomatal conductance, usually measured in mmol m−2 s−1 by a porometer, estimates the rate of gas exchange (i.e., carbon dioxide uptake) and transpiration (i.e., water loss as water vapor) through the leaf stomata as determined by the degree of ...
may be used as a reference value to validate the data, by summing the total stomatal conductance
of all
leaf classes within the canopy.
See also
*
Ecohydrology
*
Stomatal conductance Stomatal conductance, usually measured in mmol m−2 s−1 by a porometer, estimates the rate of gas exchange (i.e., carbon dioxide uptake) and transpiration (i.e., water loss as water vapor) through the leaf stomata as determined by the degree of ...
*
Transpiration
Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. Water is necessary for plants but only a small amount of water taken up by the roots is used for growth a ...
References
Plant physiology