### 2.20.1.4. 14.1.4 Background Litterfall[¶](#background-litterfall "Permalink to this headline")

Both evergreen and stress-deciduous phenology algorithms can specify a litterfall flux that is not associated with a specific offset period, but which occurs instead at a slow rate over an extended period of time, referred to as background litterfall. For evergreen types the background litterfall is the only litterfall flux. For stress-deciduous types either the offset period litterfall or the background litterfall mechanism may be active, but not both at once. Given a specification of the background litterfall rate (\\({r}\_{bglf}\\), s\-1), litterfall carbon fluxes are calculated as

(2.20.32)[¶](#equation-20-32 "Permalink to this equation")\\\[CF\_{leaf,litter} =r\_{bglf} CS\_{leaf}\\\]

(2.20.33)[¶](#equation-20-33 "Permalink to this equation")\\\[CS\_{froot,litter} =r\_{bglf} CS\_{froot} ,\\\]

with corresponding nitrogen litterfall and retranslocation fluxes:

(2.20.34)[¶](#equation-20-34 "Permalink to this equation")\\\[NF\_{leaf,litter} ={CF\_{leaf,litter} \\mathord{\\left/ {\\vphantom {CF\_{leaf,litter} CN\_{leaf\\\_ litter} }} \\right.} CN\_{leaf\\\_ litter} }\\\]

(2.20.35)[¶](#equation-20-35 "Permalink to this equation")\\\[NF\_{froot,litter} ={CF\_{froot,litter} \\mathord{\\left/ {\\vphantom {CF\_{froot,litter} CN\_{froot} }} \\right.} CN\_{froot} }\\\]

(2.20.36)[¶](#equation-20-36 "Permalink to this equation")\\\[NF\_{leaf,retrans} =\\left({CF\_{leaf,litter} \\mathord{\\left/ {\\vphantom {CF\_{leaf,litter} CN\_{leaf} }} \\right.} CN\_{leaf} } \\right)-NF\_{leaf,litter} .\\\]

