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Table 2 A list of the abbreviations and symbols used in the text and in equations

From: Using a stand-level model to predict light absorption in stands with vertically and horizontally heterogeneous canopies

Symbol Description
APAR Absorption of photosynthetically active radiation (PAR) (MJ m−2 month−1)
e % Relative average error
ζ Fraction of ground area covered by the canopy
f H Fraction of PAR that is absorbed by a homogeneous canopy
f i Fraction of PAR that is absorbed by species i
i Indicates the i th species of n species
j Indicates the j th canopy layer of n layers
k Light extinction coefficient
k H Light extinction coefficient of a homogeneous canopy
H b Height to crown base (m)
h m The mid-crown-height (m) of a layer or species; given as (height – H b )/2 + H b
λ h Empirical parameter to account for the effects of horizontal heterogeneity within the j th canopy layer
λ v Empirical parameter to quantify the vertical structure of a canopy layer and to partition layer APAR to each species within the layer
L Leaf area index (m2 m−2)
L A Individual tree leaf area (m2)
LAD Leaf-area density in terms of leaf area per crown volume (m2 m−3)
LCL Live-crown length (m)
MAE% Relative mean absolute error
MSE Mean square error
O Observed calculations from the tree-level model (Maestra)
O ˜ Mean of O
P Predicted values from the stand-level model
P ˜ Mean of P
S A Crown surface area of individual trees (m2)
v frac Sum of the crown volume (m3) of all crowns within a given layer within one hectare divided by the total volume of that layer
ϕ Empirical parameter to quantify the horizontal structure of a canopy layer (see Appendix A)
z adj An adjusted mean midday solar zenith angle (°) (see Appendix B)