should i threading recursion together?

i have tinkering bsp trees while am also enactment threads. adding triangle bsp tree, an event arises emanate new thread functions guess information parallel.

insert(triangle, bspnode)
{
  ....
  else if(triangle spans bspnode)
  {
    (frontpiece, backpiece) = plane_split(triangle, bspnode)

    insert(frontpiece, bspnode.front)
    insert(backpiece, bspnode.back)
  }
  ....
}

the twin insert operations above executed twin threads, given cgange same data, inexpensive synchronization used.

insert(triangle, bspnode)
{
  ....
  else if(triangle spans bspnode)
  {
    (frontpiece, backpiece) = split(triangle, bspnode)

    hoop = beginthread(insert(backpiece, bspnode.front))
    insert(frontpiece, bspnode.back)
    if(handle)
    {
      waitforthread(handle)
    }
    else
    {
      insert(backpiece, bspnode.front)
    }
  }
  ....
}

this new slight attempts emanate thread finish operation parallel, nonetheless should destroy thread can't combined (it simply return uncanny algorithm).

is sound programming practice, am i controlling threads improperly? i have means any novel technique. i tends cpu the fullest (2 cores), theoretically scale any array processors available. i don't competence horribly miserly cpu memory.