This 2D companion drives the identical response curves as the 3D canopy, drawn instead as a bar chart: each vertical bar is one leaf cluster whose height and colour track its own instantaneous carbon gain, a sun/moon dot sweeps the arc above driving the day/night cycle, and a scrolling line graph beneath the canopy plots average GPP, NPP and respiration over the last few simulated minutes so trends are easy to read at a glance.
GPP = Pmax · L/(L+K_L) · [CO2]/([CO2]+K_C) · exp(−(T−Topt)²/2σ²)
Rd = R0 · Q10^((T−20)/10)
NPP = GPP − Rd
- C3 (most trees, wheat, rice): saturates at moderate light, strongly CO₂-limited (photorespiration), optimum ≈ 25°C. Rising CO₂ helps it the most.
- C4 (maize, sugarcane, most grasses): a carbon-concentrating pump keeps it CO₂-saturated even at today's ambient level, tolerates more light and heat, optimum ≈ 35°C.
- CAM (cacti, succulents): stomata open only at night to fix CO₂ into malic acid (the store gauge fills after dark); during the day stored carbon is released internally and turned into sugar using daylight, without losing water through open stomata.
- Peak light / CO₂ / temperature sliders set the environment every bar responds to; the scrolling graph below the canopy is the same GPP/NPP signal eddy-covariance towers measure at ecosystem scale.