Canopy conductance

{{Short description|Dimensionless quantity}}

Canopy conductance, commonly denoted $g\_c$, is a dimensionless quantity characterizing radiation distribution in tree canopy. By definition, it is calculated as a ratio of daily water use to daily mean vapor pressure deficit (VPD).{{cite web|url=http://www.kainet.or.ke/documents/canopy-conductance-estate-tea-kenya|title=Canopy conductance of estate tea in Kenya|author1=Callander, B.A.|author2=Woodhead, T.|publisher=Elsevier|access-date=2014-01-15|archive-url=https://archive.today/20140115105352/http://www.kainet.or.ke/documents/canopy-conductance-estate-tea-kenya|archive-date=2014-01-15|url-status=dead}} Canopy conductance can be also experimentally obtained by measuring sap flow and environmental variables.{{Cite journal|title = Transpiration and canopy conductance in a eucalypt plantation using shallow saline groundwater|first1 = Jim|last1 = Morris|last2 = Mann|first2 = Louise|first3 = John|last3 = Collopy|journal = Tree Physiology|volume = 18|issue = 8–9|pages = 547–555|year = 1998|doi = 10.1093/treephys/18.8-9.547| pmid=12651341 |doi-access = free}} Stomatal conductance may be used as a reference value to validate the data, by summing the total stomatal conductance $g\_s$ of all leaf classes within the canopy.{{cite web|url=http://www.life.illinois.edu/plantbio/wimovac/canopy.htm|title=WIMOVAC Canopy Processes Module|publisher=University of Illinois|year=1998|author=WIMOVAC}}

$g\_c\; =\; \backslash sum\_\{layer\_1\}^\{layer\_N\}\; (g^i\_\{s,sun\}\; \backslash cdot\; l\_\{sun\}^i)\; +\; (g\_\{s,shade\}\; \backslash cdot\; l\_\{shade\})$