A surgical system, comprising a surgical tool including a shaft and an end effector formed at a distal end thereof, the end effector having a clamping element and an ultrasonic blade, the clamping element being movable relative to the ultrasonic blade to clamp and treat tissue disposed between the clamping element and the ultrasonic blade. The system further comprising a closure mechanism configured to move the clamping element towards the ultrasonic blade from an open configuration to a closed configuration at a predetermined clamping velocity and a control system. The control system configured to maintain a first clamping velocity greater than a minimum clamping velocity until a predetermined clamping force threshold is achieved, determine a closure parameter including an amount of time and displacement required to reach the force threshold, determine a tissue characteristic based on the closure parameter, and deliver energy to the ultrasonic blade to treat tissue according to a feathering treatment protocol based on the tissue characteristic.
