Climate forecasts suggest that [CO₂] in the atmosphere will continue to increase. Structural and ecophysiological responses to elevated air [CO₂] (e[CO₂]) in tree species are contradictory due to species-dependent responses and relatively short-term experiments. It was hypothesized that long-term exposure (4 year) to e[CO₂] would change canopy structure and function of Coffea arabica trees. Coffee plants were grown in a FACE (free air CO₂ enrichment) facility under two air [CO₂]: actual and elevated (actual + approx. 200 μL CO₂ L^–1). Plants were codified following the VPlants methodology to obtain coffee mock-ups. Plant canopies were separated into three 50 cm thick layers over a vertical profile to evaluate their structure and photosynthesis, using functional–structural plant modelling. Leaf area was strongly reduced on the bottom and upper canopy layers, and increased soil carbon concentration suggested changes in carbon partitioning of coffee trees under e[CO₂]. Increased air [CO₂] stimulated stomatal conductance and leaf photosynthesis at the middle and upper canopy layers, increasing water-use efficiency. Under e[CO₂], plants showed reduced diameter of the second-order axes and higher investment in the youngest third to fifth-order axes. The responses of Arabica coffee grown under long-term exposure to e[CO₂] integrated structural and functional modifications, which balanced leaf area loss through improvements in leaf and whole-plant photosynthesis.

A method was developed for assessing the three dimensional (3-D) geometric structure of white clover canopies. 3-D co-ordinates of pre-defined point