Thiessen polygons A diagram used in studies of plant competition in which the position of each plant is plotted and joined by a straight line to each of its neighbours. The joining lines are then bisected by lines drawn at right angles to them, forming polygons. The size of polygons indicates the density of plants.

Thiessen polygons A diagram used in studies of plant competition in which the position of each plant is plotted and joined by a straight line to each of its neighbours. The joining lines are then bisected by lines drawn at right angles to them, forming polygons. The size of polygons indicates the density of plants.