What is the source of the data (leaf C:N) in tr.cli ?

• What are the following variables? How were they calculated?
  • climate data was extracted from CRU monthly data during 2001-2010
  • mgdd0: growth temperature
  • mVPD0 : VPD averaged over growth period, temperature input is daytime temperature
  • mPAR0 : PPFD
  • gdday0: used to calculate f
  • f : fraction of the growing season length >0˚C (gdday0/365)
  • alpha : AET/PET

Document calculation of leaf C:N from Vcmax25 and LMA:

tr.cli$pre.Nm <- 0.4796606 * (tr.cli$pre.Vc25 / tr.cli$pre.LMA) + 1.849738 
tr.cli$pre.cn <- 48 / tr.cli$pre.Nm  # global Cmass = 48 according to Dong Ning

Does this assume a relationship between leaf Vcmax25 (in mol m-2 s-1) and Narea (in gN m-2) of

$$ N_\text{area} = 1.849738 \times \text{LMA} + 0.4796606 \times V_\text{cmax} $$

Not exactly. The unit of Nmass is %, thus, mathematically Narea = (1.84LMA + 0.48Vcmax25)/100.

Reference for LMA-evergreen prediction? Doesn’t correspond to Eq. 34 in bioRxiv pre-print)

• The coefficients of mPAR0, mgdd0 and f are theoretical values shown in Table S3
• The coefficient of alpha and intercept are tuned based on my analysis in China

LMAev <- exp( 0.5 * log(tr.cli$mpar0)
               - 0.013 * tr.cli$mgdd0
               - 0.62 * log(tr.cli$alpha)
               + 0.25 * log(tr.cli$f)
               + 3.759
              )

Any reference for “LSMs parameters” of leaf C:N: the table below is from CLM5 tech note