Enlarge a tree (lyx and forest package)

Question

I am using Lyx and the forest package to create a very complicated tree. I've just finished it and it's good but when I generate the pdf, the result is too small. I need a code to enlarge the tree (the line between 95184 M and 1234 56789 (Murbacensis)(*) is not visible too, probably cause of the small dimensions). Could anyone help me? Thank you in advance :)

\@ifpackagelater{forest}{2016/02/20}{%
\useforestlibrary*{linguistics}
}{}

\makeatother

\usepackage{babel}
\begin{document}
\selectlanguage{italian}%
\begin{sidewaysfigure}
\begin{forest}
GP1[, fit=rectangle
[[14, edge=dashed, name=m[214936\\(Treuirensis)\\({*}), edge=dashed,        name=g[[21493\\S F, calign=first][21493[, fit=rectangle[23\\C[, phantom              [2367\\$\varphi$, name=d]]]][2149\\L]]]]]]
[[2367, edge=dashed, fit=rectangle, name=p[3\\(Gyr.)\\({*}{*}),      edge=dashed][23678, fit=band, name=a[23+678, name=o[1234+678, name=l[1234     56789\\(Murbacensis) ({*}), fit=rectangle, name=h[95184\\M]]]]]]]
[[8, edge=dashed, fit=band, name=b]]
[[95, edge=dashed, fit=band, name=f[67849\\G, name=i][95,   edge=dashed[95, edge=dashed,  fit=band[6785\\B, edge=dashed][95\\F P\\(D   R), edge=dashed[, phantom [8\\(Frag. Cuaiac.)\\({*}), fit=band,    name=c]]]]]]
 ]]]]]
 \draw[dashed,-] (b) to [out=180, in=400] (a);
 \draw[dashed,-] (a) to [out=south east, in=north west] (c);
 \draw[-] (a) to [out=200, in=350] (d);
 \draw[dashed,-] (f) to [out=150, in=400] (g);
 \draw[dashed,-] (f) to [out=south west, in=east] (h);
 \draw[dashed,-] (i) to [out=west, in=east] (l);
 \draw[dashed,-] (m) to [out=south east, in=west] (l);
 \draw[dashed,-] (g) to [out=south east, in=south west] (o);
 \end{forest}
 \centering
 \end{sidewaysfigure}
 \selectlanguage{english}%

 \end{document}

Answer 1

probably i misunderstand what you like to achieve. with use of addition mentioned in my comment above i obtain the following picture of tree:

in comparison to picture obtained with your code the distances between nodes are increased. is this what you looking for?

difference to your code is:

\documentclass{article}
\usepackage[showframe]{geometry}
\usepackage{rotating}
\usepackage{forest}
\useforestlibrary*{linguistics}

\begin{document}%
%\begin{sidewaysfigure}
\centering
\begin{forest}
    GP1,
    for tree={ 
    l sep=7mm, % set minimal level distance between nodes
    s sep=5mm  % set minimal sibling distance between nodes
            },
[, fit=rectangle
... <the rest of your code> ...
 \end{forest}
% \end{sidewaysfigure}
\end{document}

i not use sidewaysfigure environment since i estimate that image orientation doesn't limit the picture size.