Forest package and weird bracket behaviour

Question

I am using forest package to write some algebra with planar trees. However, when I combine automatically sized brackets with my forest picture, the bracket size and position is completely wrong: it goes all the way below the forest. How do I get the adequately sized and positioned brackets?

\documentclass{article}
\usepackage[utf8]{inputenc}

\usepackage{forest}

\begin{document}
$$\left ( \begin{forest}
for tree = {grow'=90,circle, fill, minimum width = 4pt, inner sep = 0pt, s sep = 13pt}
[{},phantom
[{},name = one [[]] [[][]] ]
[{},name = two [[]] [[]] ]
]
\draw[black] (one) -- (two);
\end{forest},
\begin{forest}
for tree = {grow'=90,circle, fill, minimum width = 4pt, inner sep = 0pt, s sep = 13pt}
[{},phantom
[{},name = one [[]] [[][]] ]
[{},name = two [[]] [[]] ]
[{},name = three [  [][]]]
[{},name = four [ [] [] []] [[]]  ]
]
\draw[black] (one) -- (two) -- (three) -- (four);
\end{forest} \right )$$

\end{document}

Answer 1

Do not use $$ ... $$ but use \[ ... \] instead. You need to center the tree vertically, which can be done with \vcenter.

\documentclass{article}
\usepackage[utf8]{inputenc}

\usepackage{forest}

\begin{document}
\[\left (\vcenter{\hbox{\begin{forest}
for tree = {grow'=90,circle, fill, minimum width = 4pt, inner sep = 0pt, s sep = 13pt}
[{},phantom
[{},name = one [[]] [[][]] ]
[{},name = two [[]] [[]] ]
]
\draw[black] (one) -- (two);
\end{forest},
\begin{forest}
for tree = {grow'=90,circle, fill, minimum width = 4pt, inner sep = 0pt, s sep = 13pt}
[{},phantom
[{},name = one [[]] [[][]] ]
[{},name = two [[]] [[]] ]
[{},name = three [  [][]]]
[{},name = four [ [] [] []] [[]]  ]
]
\draw[black] (one) -- (two) -- (three) -- (four);
\end{forest}}} \right )\]

\end{document}