On the Ecology of Mountainous Forests in a Changing Climate: A ...

74 Chapter 3
where gLign c is litter lignin content predicted according to Eq. 3.50 (Berg et al. 1985),
and gNMR c is the nitrogen to organic matter ratio of the litter (Eq. 3.51).
gLign c = kLignA + kLignB ·
LOM c
LOM c,init
(3.50)
gNMR c = LN c
LOM c
(3.51)
The lignin parameters in Eq. 3.50 are calculated from data compiled by Pastor & Post
(1985, p.139):
kLignA = 0.4929 + 19.1784·kNC (3.52)
kLignB = 0.01558 – 0.673·kLignA (3.53)
Tab. 3.7: Symbols used in FORCLIM-S. Bold face denotes state variables.
Factor Symbol Unit Explanation Eq.
Litter decay LOM c t·ha -1 organic matter content of a litter cohort 3.49
LN c t·ha -1 nitrogen content 3.54
gLign c %/100 lignin content 3.50
gNMR c – nitrogen:organic matter content ratio 3.51
gImmob c t·ha -1·yr-1 gross nitrogen immobilization rate 3.55
gLeach c t·ha -1·yr-1 gross nitrogen leaching rate 3.56
gNetImmob c t·ha -1·yr-1 net nitrogen immobilization rate 3.54
kInitN X %/100 initial N concentration (X = F kLQ ,T,R,W)
k i
regression parameters
kLoss W %/100 decomposition parameter of wood
kLoss T %/100 decomposition parameter of twigs
kLignA %/100 regression parameter 3.52
kLignB – regression parameter 3.53
kNC – nitrogen immobilization parameter
kLeach %/100 nitrogen leaching parameter
Humus decay HN t·ha -1 nitrogen content of humus compartment 3.57
HOM t·ha -1 organic matter content 3.60
gLNC – N:C ratio of litter compartment 3.58
gAETM – AET multiplier 3.59
k i
regression parameters
kMin %/100 N mineralization rate in the absence of litter
kCM %/100 carbon:organic matter ratio of litter
kAET mm·yr -1 AET multiplier parameter
Nitrogen availability gLImmob t·ha -1·yr-1 total net nitrogen immobilization rate of litter 3.61
kNAtm t·ha -1·yr-1 input rate of atmospheric nitrogen