code: function(id, removeRoot, method, onComplete) {
              var node = this.graph.getNode(id), subids = [];
              node.eachLevel(+!removeRoot, false, function(n) {
                  subids.push(n.id);
              });
              if(method == 'replot') {
                  this.op.removeNode(subids, $.extend({ type: 'replot' }, onComplete || {}));
              } else if (method == 'animate') {
                  this.op.removeNode(subids, $.extend({ type: 'fade:seq'}, onComplete || {}));
              }
          }
docs: /*
  Method: removeSubtree
  
  Removes a subtree.
  
  Parameters:
  id - (string) The _id_ of the subtree to be removed.
  removeRoot - (boolean) Default's *false*. Remove the root of the subtree or only its subnodes.
  method - (string) Set this to "animate" if you want to animate the tree after removing the subtree. You can also set this parameter to "replot" to just replot the subtree.
  onComplete - (optional|object) An action to perform after the animation (if any).
  
  Example:
  
  (start code js)
  st.removeSubtree('idOfSubtreeToBeRemoved', false, 'animate', {
  onComplete: function() {
  alert('complete!');
  }
  });
  (end code)