Figure 5: (a) A wind tunnel experiment to assess the effect of surface roughness on the laminar flow of air over an array of small cylinders of different diameter (d) and height (h) ([118]; see[5, Figure  11.9]). (b) A sketch showing the variation in resistance of overstorey and understorey strata in a plant community to the laminar flow of wind ([109]; see [5, Figure  11.9]).