Feat: https://www.youtube.com/watch?v=CAPAa5DJuCw
Grumpy's height: 6.1 m
His head: 2.82 m
His head angle's is on different angle position.
Branch length: 15.65 m
Branch diameter: 0.88 m = 0.44 m as radius
Inspired by this calc.
Cylinder Cross-Sectional Area: 0.60821233773 sq meters
Hard wood's average tensile strength: 85.85 MPa - 85.85e+7 N/m^2
Force: 522,150,291.941 Newtons of Force, 53,244.51183 Tonnes of Force, Class M
Distance: 0.88 m (Branch's diameter)
Energy to rapidly rip it off: 522150291.941 * 0.88 = 459,492,256.908 Joules, 0.1098212851 Tons of TNT, Small Building level (9-A)
Although the branch seems to be thinner, Grumpy rapidly rips the branch off instead of stranding them off slowly, so he can scale to this.