# trees dashed lines

I would like reproduce the following tree in a mathematical text. But for copyright reasons, I cannot use includegraphics{} and I must draw this figure in latex. What do you advise me ? What is the (relatively simple) suitable package to produce the dashed lines ?

To give you a start. When trying to find an answer, I stole from (and of course upvoted) many many brilliant answers by @cfr. Hope (s)he will provide you with a less clumsy solution.

\documentclass[tikz,border=10pt]{standalone}
% stolen from nice cfr answers such as https://tex.stackexchange.com/a/278184/121799
\usepackage{forest}
\begin{document}
\begin{forest}
anchors/.style={anchor=#1,child anchor=#1,parent anchor=#1},
/tikz/every node/.append style={font=\footnotesize},
for tree={
s sep=5mm,l=15mm,
if n=0{anchors=east}{
if n=1{anchors=east}{anchors=west}},
content format={$\forestoption{content}$},
},
anchors=south, outer sep=2pt,
nodot/.style={content format={},draw=none},
if content={}{}{dot={fill}}
[\phi,dot=fill
[y_{1,1},dot=fill
[y_{1,1}y_{2,1},dot=fill
[,edge=dashed]
[,edge=dashed]]
[y_{1,1}y_{2,2},dot=fill
[,edge=dashed]
[,edge=dashed]]
[,edge=dashed]
[y_{1,1}y_{2,{m_2}},dot=fill
[,edge=dashed]
[,edge=dashed]]
]
[y_{1,1},dot=fill
[,edge=dashed]
[,edge=dashed]
]
[y_{1,{m_1}},dot=fill
[y_{{m_1},1}y_{2,1},dot=fill
[,edge=dashed]
[,edge=dashed]]
[y_{{m_1},1}y_{2,2},dot=fill
[,edge=dashed]
[,edge=dashed]]
[,edge=dashed]
[y_{{m_1},1}y_{2,{m_2}},dot=fill
[,edge=dashed]
[,edge=dashed]]
]
]
]
\end{forest}
\end{document}