Shapes of crowns are highly variable. The major types for trees are the excurrent branching habit resulting in conoid shapes and decurrent (deliquescent) branching habit, resulting in round shapes. Crowns are also characterized by their width, depth, surface area, volume, and density. Measurements of crowns are important in quantifying and qualifying plant health, growth stage, and efficiency.
Major functions of the crown include light energy assimilation via photosynthesis, energy release by respiration, and movement of water to the atmosphere by transpiration. These functions are performed by leaves. Branches of the crown provide mechanical support to distribute the leaves efficiently and serve as conduits for resources (water, nutrients, photosynthates) to perform these functions.
The crown of a plant is where the shoot starts growing.