I want to create syntactic trees and align them in LaTeX as in the picture below.

Can you help me?
I want to create syntactic trees and align them in LaTeX as in the picture below.

Can you help me?
You will need
This code will get you pretty near what you are trying to achieve:
\documentclass[]{article}
\usepackage[margin=1cm]{geometry}
\usepackage{tikz}
\usepackage{tikz-qtree}
\newcommand{\superscript}[1]{\ensuremath{^{\textrm{#1}}}}
\newcommand{\subscript}[1]{\ensuremath{_{\textrm{#1}}}}
\begin{document}
\tikzset{level 1/.style={level distance=20pt}}
\tikzset{level 2/.style={level distance=30pt}}
\tikzset{level 3+/.style={level distance=20pt}}
\tikzset{frontier/.style={distance from root=10\baselineskip}}
\begin{tikzpicture}[remember picture]
\Tree
[.{ST}
[.{NP}
[.NNP \node[](john){John}; ]
[.NNP \node[](smith){Smith}; ] ]%done
[.{VP} % level 2 VP contains VP1 CC VP2
[.{VP\subscript{1}}
[.{VBD} \node[](walked){walked}; ]
[.{NP}
[.{PRP\$} \node[](his){his}; ]
[.{NN} \node[](dog){dog}; ] ] ]
[.{CC} \node[](and){and}; ]
[.{VP\subscript{2}}
[.ADVP
[.{RB} \node[] (afterwards) {afterwards}; ] ]
[.{VBD} \node[] (met) {Met}; ]
[.{NP}
[.{NNP} \node[] (mary) {Mary}; ] ] ] ]
[.{.}
[[[\node[](dot){.}; ] ] ] ] ] ]
\begin{scope}[yshift=-9.5cm,xshift=-3cm,grow'=up]
\Tree
[.{ST}
[.{NP}
[.{NNP} \node[] (john2) {John}; ]
[.{NNP} \node[] (smith2) {Smith}; ]]
[.{VP}
[.{VBD} \node[] (walked2) {walked}; ]
[.{NP}
[.{PRP\$} \node[] (his2) {his}; ]
[.{NN} \node[] (dog2) {dog}; ] ]]
[.{.}
[[[[\node[] (dot2){.}; ]]]] ] ]
\end{scope}
\begin{scope}[yshift=-9.5cm,xshift=3cm,grow'=up]
\Tree
[.{ST}
[.{NP}
[.{PRP} \node[] (he2) {He}; ] ]
[.{VP}
[.{VBD} \node[] (met2) {met}; ]
[.{NP}
[.{NNP} \node[] (mary2) {Mary}; ] ]
[.{ADVP}
[.{RB} \node[] (later2) {later}; ] ] ]
[.{.}
[[[[{.} ]]]] ] ]
\end{scope}
%draw the lines
\begin{scope}[remember picture, overlay]
\draw[black,dotted,thick](john) to (john2);
\draw[black,dotted,thick] (smith) to (smith2);
\draw[black,dotted,thick] (walked)to (walked2);
\draw[black,dotted,thick] (his) to (his2);
\draw[black,dotted,thick] (dog) to (dog2);
\draw[black,dotted,thick] (dot) to [out=220,in=50] (dot2);
\draw[black,dotted,thick] (met) to (met2);
\draw[black,dotted,thick] (mary) to (mary2);
\end{scope}
\end{tikzpicture}
\end{document}
\end{document}
I will post updated code once I get the leaf nodes aligned! I am not sure why the . leaf is not being aligned with the rest of the leaves.
UPDATE The solution to the problem of getting the . leaf nodes aligned with the other leaves is to nest it within brackets [[[]]], which puts it on a deeper level.
Sample Output

If you are looking for more information, check out Alan Munn's informative answer here.
tikz-qtreepackage gives an example similar to this in its documentation. Try that and come back with a sample document if you're having problems. There are also lots of [tag:tikz-qtree] questions on the site. – Alan Munn Apr 28 '13 at 16:01