Below is what picture i want

Words of level 1: Rule
Words of level 2: Length Pattern Arcs
Words of level 3: T1 T2 A1
Words of level 4: term_index term pos_tag ne_tag term_index term pos_tag ne_tag start_index end_index semantic_type
String of bottom line: 2 [1][][][LOC] [2][][][LOC] -> 1-2:loc-cons
Below is my current code, and the picture generated by it.
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{trees}
\begin{document}
\pagestyle{empty}
\begin{tikzpicture}[edge from parent fork down]
\tikzstyle{level 2}=[level distance=1.3cm, sibling distance=10cm]
\tikzstyle{level 3}=[level distance=2.0cm, sibling distance=5cm]
\tikzstyle{level 3}=[level distance=2.0cm, sibling distance=3cm]
\tikzstyle{r}=[rotate=45]
\node {Rule}
child {node {Length}
child {node {2}}
}
child {node {Pattern}
child {node {$T_1$}
child {node[r] {term\_index}}
child {node[r] {term}}
child {node[r] {pos\_tag}}
child {node[r] {ne\_tag}}
}
child {node {$T_2$}
child {node[r] {term\_index}}
child {node[r] {term}}
child {node[r] {pos\_tag}}
child {node[r] {ne\_tag}}
}
}
child {node {Arcs}
child {node {$A_1$}
child {node[r] {start\_index}}
child {node[r] {end\_index}}
child {node[r] {semantic\_type}}
}
};
% \node{2[][][][LOC] [2][][][LOC] \rightarrow 1-2:loc-cons};
\end{tikzpicture}
\end{document}

Can anyone help me with this, thanks a lot!

tikz-qtreefor this. Here are some related questions: How to draw up a hierarchical tree diagram for taxonomic classification and Joining two branches of a family tree. – Alan Munn May 30 '12 at 16:42