Table II. Interchangeable water-use efficiency indexes.

Values for g_1M (see Eq. 3) are shown for different plant functional types, as used when implementing the Medlyn et al. (2011) stomatal model in CABLE (De Kauwe et al., 2015; Kala et al., 2015) and in the CLM4.5 simulations in Figures 9 and 10 below. These values are based on those given by Lin et al. (2015) but differ slightly in some cases. Equivalent approximate values are derived from g_1M for λ, g₁, and mean c_i/c_a using Equations 4, 5, and 9 (25°C, H = 0.8, Γ* = 40 μmol mol⁻¹). In the model implementation, g₀ = 0, as was the case for Lin et al. (2015) when determining g_1M from gas-exchange data. Plant types with lower values for g_1M, g₁, λ, or c_i/c_a have comparatively higher water-use efficiency.

Plant Type	g1M	g1	λ	ci/ca
	kPa0.5		mmol water μmol−1 CO2
C3 crop	5.79	16.5	4.47	0.88
C3 grass	5.25	15.1	3.68	0.87
Shrub	4.70	13.8	2.95	0.85
Deciduous broadleaf tree	4.45	13.1	2.64	0.85
Evergreen broadleaf tree	4.12	12.3	2.26	0.84
Evergreen needleleaf tree	2.35	7.88	0.74	0.75
Deciduous needleleaf tree	2.35	7.88	0.74	0.75
Arctic tundra	2.22	7.55	0.66	0.74
C4 grass	1.62	6.05	0.35	0.67