Assign explicit coordinates to the vertices of the tree.
In[]:=
coords={{0,0}};Do[coords=Join[coords,Table[{i,j/3},{j,-i,i,2}]],{i,1,2}]
Assign directed edges between the vertices of the tree.
In[]:=
verts={"S""dS","S""uS","dS""
2
d
S","dS""duS","uS""duS","uS""
2
u
S"}
Out[]=
{SdS,SuS,dS
2
d
S,dSduS,uSduS,uS
2
u
S}
Plot the tree.
In[]:=
TreePlot[verts,DirectedEdgesTrue,VertexShapeFunction(Inset[Framed[Text[#2],BaseStyle{Black},BackgroundWhite],#1]&),PlotStyle{FontSize12},EdgeStyleThick,VertexCoordinatescoords]
Out[]=
RulesTree[] seems like it should do the job, but the tree does not recombine at the node “duS”.
In[]:=
RulesTree["S"->{"dS"->{"
2
d
S","duS"},"uS"->{"duS","
2
u
S"}}]
Out[]=