A combination of a tree removal device and working vehicle for coupling the device thereon such that the combination is arranged for slicing tree roots. The working vehicle has a front element which is pivotable relative to a frame of the vehicle about a lateral axis in front of a forward end of the frame. The tree removal device includes an attachment portion for coupling to the front element and a knife element having a blade portion. The blade portion has front and rear edges arranged for engaging the ground in respective forward and backward directions of movement of the vehicle which are sharpened so as to perform a cutting action in the respective direction of movement when the blade portion engages the ground. Furthermore, the knife element is pivotable relative to the attachment about an axis in a vertical plane that divides the vehicle into symmetrical halves.