Characterizing wind-induced reconfiguration of coaxial branched tree

Tree dynamics have been extensively studied because of their reconfiguration ability under oncoming wind flow. However, there is still a gap in the effect of crown configuration on the tree reconfiguration. The present study examined the wind-induced reconfiguration performance of 9 coaxial branched trees with three different pruning techniques by wind tunnel tests, to comprehensively and thoroughly reveal the effects of crown configurations on tree reconfiguration. Results showed that normalized crown mass is the best parameter for correlating with the maximum normalized drag force acting on the tree. Meanwhile, it was found that area reduction effect decreases with an increase in LAI₁ (the ratio of leave area and ground area) and LAI₂ (the ratio of leave area and frontal area). Streamlining effect is gradually enhanced with an increase in λ_ct (the ratio of crown height and trunk height), but shows a trend of first increasing and then decreasing with the increase of LAI₁ and LAI₂. Finally, a reconfiguration model was proposed to show the dynamic behavior of the coaxial branched tree under different dimensionless tree parameters. The revealed tree reconfiguration mechanism and the reconfiguration model can guide tree managers and researchers for understanding the tree behavior and tree dynamics.