Behave sub-trees

I'm using AngryAnt's Behave, and I have several sub-trees, but when I have them called I don't see the Action's handler called. I've instantiated the main tree and the sub tree, and have the main tree's Tick() method called in Update(). I don't call the sub-tree's Tick() method because that would defeat the purpose of the main tree determining whether or not to call the sub-tree.

public class NonInteractiveCharacter : MonoBehaviour { private Behave.Runtime.Tree nicSelectorTree = null; private Behave.Runtime.Tree idleTree = null;

 void Awake () 
 {
     nicSelectorTree = BLNICLibrary.InstantiateTree(
         BLNICLibrary.TreeType.NonInteractiveCharacters_NICSelector, 
         new NICSelectorAgent());

     idleTree = BLNICLibrary.InstantiateTree(
         BLNICLibrary.TreeType.NonInteractiveCharacters_Idle, 
         new NICIdleAgent());
 }

 // Update is called once per frame
 void Update () 
 {
     nicSelectorTree.Tick();

     // I shouldn't have to call idle's Tick method since it's called 
     // from the above selector tree
     //idleTree.Tick();
 }

}

Thanks in advance, Scott