code: protected synchronized void fireTreeAddition(Tree<D, ?> tree) {
  		if (this.listeners != null) {
  			final ForestListener[] list = new ForestListener[this.listeners.size()];
  			this.listeners.toArray(list);
  			final ForestEvent event = new ForestEvent(this, null, tree);
  			for (final ForestListener listener : list) {
  				listener.forestChanged(event);
  			}
  		}
  	}
docs: Fire the addition event.
  
  @param tree is the new tree in the forest.