Pruning of Buttress Roots and Stability Changes of Red Maple (Acer rubrum)

Bending moment to achieve one degree of trunk movement. Small bars indicate one unit of Standard Error.

Regression line and 95% confidence interval for the comparison of the percentage of buttress roots cut (R_cut/R_Total × 100) and the normalized force (peak force to move the trunk one degree after root cutting divided by the peak force prior to cutting roots multiplied by 100) to move the trunk one degree. This assessment procedure was defined at Method 1. F_Std = 97 – 0.8 (R_cut/R_Total × 100), r² = 0.74.

Regression line and 95% confidence interval for the comparison of the normalized cumulative sum of the widths of buttress roots cut divided by cross-sectional area of the trunk as measured at 1.37 m (∑R_{cut width}/CSA_trunk) and the normalized force (peak force to move the trunk one degree after root cutting divided by the peak force prior to cutting roots multiplied by 100) to move the trunk one degree. This assessment procedure was defined at Method 2. F_Std = 91.3 – 503 × ∑R_{cut width}, r² = 0.54.

Regression line and 95% confidence interval for the comparison of the cumulative sum of the estimated cross sectional area of all roots that were severed divided by cross-sectional area of the trunk as measured at 1.37 m (∑R_{cut area approx}/CSA_trunk × 100) compared to the normalized force (F_Std = peak force to move the trunk one degree after root cutting divided by the peak force prior to cutting roots multiplied by 100) to move the trunk one degree. This assessment procedure was defined at Method 3. F_Std = 90.4 – 28.6 (∑R_{cut area}/CSA_trunk × 100), r² = 0.51.

Red maple pulled to failure showing both cut buttress roots and broken oblique roots.