How can we draw a Christmas tree with decorations, using TikZ?

Question

I would like to use TikZ for drawing a christmas tree. Here's a start, I used the lindenmayersystems library for drawing a tree:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{lindenmayersystems}
\begin{document}
\begin{tikzpicture}
\draw [color=green!50!black, l-system={rule set={S -> [+++G][---G]TS,
  G -> +H[-G]L, H -> -G[+H]L, T -> TL, L -> [-FFF][+FFF]F}, step=4pt, angle=18,
 axiom=+++++SLFFF, order=11}] lindenmayer system -- cycle;
\end{tikzpicture}
\end{document}

I found the tree in "The Science of fractal images" by Peitgen and Saupe.

Who can help to decorate it? Or to draw another tree with Christmas decorations, such as tinsel garland (lametta), candles, baubles (Christmas balls), a tree topper? Perhaps add a shading to the green?

For celebrating Christmas, I would like to put the tree on our blog, and on the TikZ example gallery.

Answer 1

Merry Christmas everyone!

\documentclass[11pt]{scrartcl} 
\usepackage[dvipsnames,svgnames]{xcolor}  
\usepackage{tikz}
\usetikzlibrary{shapes,decorations.shapes}
\newsavebox{\mycandle}
\savebox{\mycandle}{ 
\begin{tikzpicture}[scale=.1]
\shade[top color=yellow,bottom color=red] (0,0) .. controls (1,.2) and (1,.5) .. (0,2) .. controls (-1,.5)  and  (-1,.2) .. (0,0);
\fill[yellow!90!black] (.8,0) rectangle (-.8,-5); 
\end{tikzpicture} } 

\tikzset{
  paint/.style={draw=#1!50!black, fill=#1!50},
  my star/.style={decorate,decoration={shape backgrounds,shape=star},
                  star points=#1}
}  

\begin{document}
\begin{tikzpicture} 
   \draw[fill=Maroon,ultra thick] 
   (.75,-1)  ..  controls (.5,.5)  and   (.5,3)    .. (0.5,4) 
-- (-0.5,4)  ..  controls (-.5,3) and (-.5,.5)     .. (-.75,-1) ;
\draw[ultra thick,fill=green!50!black] 
      (0,10) .. controls  (0,8)     and   (1,7)    .. (1.5,7) 
             ..  controls (1,7)     and   (1,7)    .. (0.5,7.25) 
             ..  controls (1.5,5)   and   (2.5,4)  .. (3,4)
             ..  controls (2,4)     and   (1.25,4) .. (1,4.5)
             ..  controls (2,2)     and   (3.5,2)  .. (4,2)
             ..  controls (1,1)     and   (-1,1)   .. (-4,2) 
             ..  controls (-3.5,2)  and   (-2,2)   .. (-1,4.5)
             ..  controls (-1.25,4) and   (-2,4)   .. (-3,4) 
             ..  controls (-2.5,4)  and   (-1.5,5) .. (-0.5,7.25) 
             ..  controls  (-1,7)   and   (-1,7)   .. (-1.5,7)
             ..  controls  (-1,7)   and   (0,8)    .. (0,10)
              ;
\foreach \candle in {(2,5),(-2,5),(0.5,7.5),(-0.5,7.5),(-3,2.5), (3,2.5),
                    (1.5,1.75),(-1.5,1.75)}
\node at \candle {\usebox{\mycandle}} ; 
 \node [star, star point height=.5cm, minimum size=.5cm, draw,fill=yellow,thick]
       at (0,10) {};
       \begin{scope}[decoration={shape sep=.2cm, shape size=.25cm}] 
    \draw [my star=6, paint=red]  (-4,2)
             ..  controls (0,2)     and   (1,3.5)   .. (1,4.5)
             ..  controls (1,6)     and   (0.5,6)      .. (0.5,7.25); 
    \draw [my star=6, paint=blue]  (4,2)
             ..  controls  (0,2) and (-1,3.5)      .. (-1,4.5)             
             ..  controls (-1,6)     and   (-0.5,6)      .. (-0.5,7.25);    
       \end{scope}  
\end{tikzpicture}

\end{document} 

Update version 2 : The snow arrives, I added some balls and a shade on the tree

\documentclass[11pt]{scrartcl} 
\usepackage[dvipsnames,svgnames]{xcolor}  
\usepackage{tikz}
\usetikzlibrary{%
  shapes,
  decorations.shapes,
  decorations.fractals,
  decorations.markings,
  shadows
}

\newsavebox{\mycandle}
\savebox{\mycandle}{ 
\begin{tikzpicture}[scale=.1]
\shade[top color=yellow,bottom color=red] (0,0) .. controls (1,.2) and (1,.5) .. (0,2) .. controls (-1,.5)  and  (-1,.2) .. (0,0);
\fill[yellow!90!black] (.8,0) rectangle (-.8,-5); 
\end{tikzpicture} } 

\tikzset{
  paint/.style={draw=#1!50!black, fill=#1!50},
  my star/.style={decorate,decoration={shape backgrounds,shape=star},
                  star points=#1}
}  

\begin{document}
  \begin{tikzpicture}[  ball red/.style={
    decorate,
    decoration={
      markings,
      mark=between positions .2 and 1 step 3cm
      with
      {
        \pgfmathsetmacro{\sz}{2 + .5 * rand}
        \path[shading=ball,ball color=red] (0,0) circle[radius=\sz mm];
      }
    }
  } ,ball blue/.style={
    decorate,
    decoration={
      markings,
      mark=between positions 0.1 and .9 step 3cm
      with
      {
        \pgfmathsetmacro{\sz}{2 + .5 * rand}
        \path[shading=ball,ball color=blue] (0,0) circle[radius=\sz mm];
      }
    }
  }   
]

\draw[fill=Maroon,ultra thick] 
      (.75,-1)  ..  controls (.5,.5)  and   (.5,3)    .. (0.5,4) 
   -- (-0.5,4)  ..  controls (-.5,3) and (-.5,.5)     .. (-.75,-1) ;
\shade[ultra thick, top color=green!90!black,bottom color=green!10!black] 
      (0,10) .. controls  (0,8)     and   (1,7)    .. (1.5,7) 
             ..  controls (1,7)     and   (1,7)    .. (0.5,7.25) 
             ..  controls (1.5,5)   and   (2.5,4)  .. (3,4)
             ..  controls (2,4)     and   (1.25,4) .. (1,4.5)
             ..  controls (2,2)     and   (3.5,2)  .. (4,2)
             ..  controls (1,1)     and   (-1,1)   .. (-4,2) 
             ..  controls (-3.5,2)  and   (-2,2)   .. (-1,4.5)
             ..  controls (-1.25,4) and   (-2,4)   .. (-3,4) 
             ..  controls (-2.5,4)  and   (-1.5,5) .. (-0.5,7.25) 
             ..  controls  (-1,7)   and   (-1,7)   .. (-1.5,7)
             ..  controls  (-1,7)   and   (0,8)    .. (0,10)
              ;

\foreach \candle in {(2,5),(-2,5),(0.5,7.5),(-0.5,7.5),(-3,2.5), (3,2.5),
                    (1.5,1.75),(-1.5,1.75)}
\node at \candle {\usebox{\mycandle}} ; 
\node [star, star point height=.5cm, minimum size=.5cm,draw,fill=yellow,thick]
      at (0,10) {};
\begin{scope}[decoration={shape sep=.2cm, shape size=.25cm}] 
    \draw [my star=6, paint=red]  (-4,2)
             ..  controls (0,2)     and   (1,3.5)   .. (1,4.40); 
    \draw [my star=6, paint=red]  (-1.5,5.40)
             ..  controls (0,5.40)     and   (0.5,6.5)      .. (0.5,7);  
    \draw [my star=6, paint=blue]  (4,2)
             ..  controls  (0,2) and (-1,3.5)      .. (-1,4.40);             
    \draw [my star=6, paint=blue]  (1.5,5.40)
             ..  controls (0,5.40)     and   (-0.5,6.5)      .. (-0.5,7);     
\end{scope} 
% the balls
\path[ball red] 
      (0,10) .. controls  (0,8)     and   (1,7)    .. (1.5,7) 
             ..  controls (1,7)     and   (1,7)    .. (0.5,7.25) 
             ..  controls (1.5,5)   and   (2.5,4)  .. (3,4)
             ..  controls (2,4)     and   (1.25,4) .. (1,4.5)
             ..  controls (2,2)     and   (3.5,2)  .. (4,2)
             ..  controls (1,1)     and   (-1,1)   .. (-4,2) 
             ..  controls (-3.5,2)  and   (-2,2)   .. (-1,4.5)
             ..  controls (-1.25,4) and   (-2,4)   .. (-3,4) 
             ..  controls (-2.5,4)  and   (-1.5,5) .. (-0.5,7.25) 
             ..  controls  (-1,7)   and   (-1,7)   .. (-1.5,7)
             ..  controls  (-1,7)   and   (0,8)    .. (0,10)
              ; 
\path[ball blue] 
      (0,10) .. controls  (0,8)     and   (1,7)    .. (1.5,7) 
             ..  controls (1,7)     and   (1,7)    .. (0.5,7.25) 
             ..  controls (1.5,5)   and   (2.5,4)  .. (3,4)
             ..  controls (2,4)     and   (1.25,4) .. (1,4.5)
             ..  controls (2,2)     and   (3.5,2)  .. (4,2)
             ..  controls (1,1)     and   (-1,1)   .. (-4,2) 
             ..  controls (-3.5,2)  and   (-2,2)   .. (-1,4.5)
             ..  controls (-1.25,4) and   (-2,4)   .. (-3,4) 
             ..  controls (-2.5,4)  and   (-1.5,5) .. (-0.5,7.25) 
             ..  controls  (-1,7)   and   (-1,7)   .. (-1.5,7)
             ..  controls  (-1,7)   and   (0,8)    .. (0,10)
              ; 
 % the snow
\foreach \i in {0.5,0.6,...,1.6}
     \fill [white!80!blue,decoration=Koch snowflake,opacity=.9]
           [shift={(rand*5,rnd*8)},scale=\i]
           [double copy shadow={opacity=0.2,shadow xshift=0pt,
           shadow yshift=3*\i pt,fill=white,draw=none}]
        decorate {
          decorate {
            decorate {
              (0,0) -- ++(60:1) -- ++(-60:1) -- cycle
            }
          }
        };                  
\end{tikzpicture}

\end{document} 

Answer 2

Just in case the code isn't clear from behind the picture, here it is in full:

\documentclass{article}
\usepackage{listings}
\usepackage{tikz}
\usetikzlibrary{%
  lindenmayersystems,
  decorations.pathmorphing,
  decorations.markings,
  shapes.geometric,
  calc%
}
\tikzset{
  tinsel/.style={
    #1,
    rounded corners=10mm,
    ultra thin,
    decorate,
    decoration={
      snake,
      amplitude=.1mm,
      segment length=10,
    }
  },
  baubles/.style={
    decorate,
    decoration={
      markings,
      mark=between positions .3 and 1 step 2cm
      with
      {
        \pgfmathsetmacro{\brad}{2 + .5 * rand}
        \path[shading=ball,ball color=#1] (0,0) circle[radius=\brad mm];
      }
    }
  },
  lights/.style={
    decorate,
    decoration={
      markings,
      mark=between positions 0 and 1 step 1cm
      with
      {
        \pgfmathparse{rand > 0 ? "dart" : "kite"}
        \let\lshape\pgfmathresult
         \pgfmathsetmacro{\tint}{100*rnd}
        \node[rotate=90,\lshape,shading=ball,inner sep=1pt,ball color=red!\tint!yellow] {};
      }
    }
  }
}

\begin{document}
\begin{center}
\tikz[remember picture,overlay] \coordinate (star) at (0,-1);
\end{center}

\lstinputlisting[
  breaklines=true,
  language=TeX,
  basicstyle=\tiny,
  firstline=63,
  lastline=103]{\jobname.tex}

\begin{tikzpicture}[overlay,remember picture]
\path (star) +(-50:7) coordinate (rhs) +(-130:7) coordinate (lhs);
\draw[brown!50!black,line width=5mm,line cap=round] (star) ++(-90:6.8) -- ++(0,-1) coordinate (base);
\node[scale=-1,trapezium,fill=black,minimum size=1cm] at (base) {};
\foreach \height/\colour in {%
  .2/blue,
  .4/yellow,
  .6/red,
  .8/orange,
  1/pink%
} {
  \draw[tinsel=\colour] ($(star)!\height!(lhs)$) to[bend right] ($(star)!\height!(rhs)$);
}
\path (star);
\pgfgetlastxy{\starx}{\stary}
\begin{scope}[xshift=\starx,yshift=\stary,yshift=-7cm]
\draw[color=green!50!black, l-system={rule set={S -> [+++G][---G]TS,  G -> +H[-G]L, H -> -G[+H]L, T -> TL, L -> [-FFF][+FFF]F}, step=4pt, angle=18, axiom=+++++SLFFF, order=11}] lindenmayer system -- cycle;
\end{scope}
\foreach \height/\colour in {%
  .1/pink,
  .3/red,
  .5/yellow,
  .7/blue,
  .9/orange%
} {
  \draw[tinsel=\colour] ($(star)!\height!(lhs)$) to[bend right] ($(star)!\height!(rhs)$);
}
\foreach \height in {.15,.35,...,1} {
  \draw[lights]  ($(star)!\height!(lhs)$) to[bend right] ($(star)!\height!(rhs)$);
}
\foreach \angle/\colour in {
  -50/red,
  -70/yellow,
  -90/blue,
  -110/pink,
  -130/purple%
} {
  \draw[baubles=\colour] (star) -- ++(\angle:7);
}
\node[star,star point ratio=2.5,fill=yellow,minimum size=1cm] at (star) {};
\end{tikzpicture}
\end{document}

Answer 3

Another tree that can be decorated:

Merry Christmas, everybody!

\documentclass[border=5mm]{standalone}
\usepackage{pgfplots}

\begin{document}
%
\begin{tikzpicture}
\begin{axis}[
    hide axis, clip=false,
    y domain=0:2*pi,
    samples=30,axis equal, view={45}{20}]

\addplot3 [domain=0:4,surf,shader=flat,z buffer=sort,fill=green!50!brown, draw=green!50!black, line join=bevel] 
    ({(1.3*x-floor(x))*x^0.5*cos(deg(y))},
     {(1.3*x-floor(x))*x^0.5*sin(deg(y))},
     {-5*x});

\addplot3 [domain=0:4.5, samples=10, samples y=0, fill=yellow!85!red, draw=yellow!55!red] ({0},{sin(x/5*360) * (1 - x + floor(x)) },{cos(x/5*360) * (1 - x + floor(x) )  + 0.5}) -- cycle;
\end{axis}
\end{tikzpicture}%
%
\end{document}

Answer 4

Here's mine:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{scopes,svg.path,shapes.geometric,shadows}
\begin{document}
\begin{tikzpicture}[
  mystar/.style={star, minimum size=2cm, star point ratio=2.5, shade, thick,
    line join=round, color=yellow!80!black, draw=red!20!black,
    top color=yellow!80!white, bottom color=yellow!60!black},
  mytree/.style={scale=0.5, rotate=180, draw=green!60!black, thick,
    line join=round, inner color=green!60!yellow, outer color=green!50!black},
  myball/.style={shade, ball color=#1, circular drop shadow={
    shadow xshift=0pt, shadow yshift=-.5ex, fill=green!40!black}}
  ]
  {[mytree]
  \shadedraw svg "M355,430
    q90,10 105,-85 30,0 50,-30 20,30 50,30 50,-20 100,0 10,88 105,85
    -45,90 -205,25 Q400,520 355,430";
  \shadedraw svg "M380,325
    q83,10 105,-80 25,0 35,-30 20,25 40,30 20,-10 35,-25 20,20 40,25
    25,90 105,82 -15,50 -120,15 -30,-2 -60,12 -30,0 -52,-28
    C490,370 380,360 380,325";
  \shadedraw svg "M435,225
    q65,-8 90,-70 35,40 70,0 25,60 90,70 -30,52 -90,5 -36,48 -73,-3
    C520,254 445,265 435,225";
  \shadedraw svg "M470,139
    q50,5 90,-80 50,90 90,80 -30,30 -50,20 -40,45 -78,0
    Q500,170 470,139";
  }
  %\shadedraw svg[scale=0.5,rotate=180]
  %"M460,532 q50,-8 q77,-45 v-20 a20,13 0 1 1 48,0 v20 q30,40 77,45";
  %pgf/tikz doesn't like the arc operation, as stated in manual

  \node[mystar] at (-9.85,-1) {$\lambda$};

  \shade[myball=blue]   (-9.7,-2.2)   circle (.2cm);
  \shade[myball=red]    (-9.2,-3.8)   circle (.2cm);
  \shade[myball=green]  (-10.3,-4)    circle (.4cm);
  \shade[myball=yellow] (-8.95,-5.4)  circle (.4cm);
  \shade[myball=red]    (-10.7,-6.1)  circle (.4cm);
  \shade[myball=blue]   (-10.8,-5)    circle (.2cm);
  \shade[myball=yellow] (-9.5,-6.7)   circle (.2cm);
  \shade[myball=green]  (-8.3,-7.6)   circle (.4cm);
  \shade[myball=yellow] (-11.7,-7.6)  circle (.4cm);
  \shade[myball=blue]   (-10.5,-7.8)  circle (.2cm);
\end{tikzpicture}
\end{document}

which looks like:

Merry Christmas!

Answer 5

I have learned a couple of new things in TikZ and created an own minimalistic version loosely based on Altermundus' first creation (and a beautiful one it is). Hopefully he does not mind. Merry Christmas to all of you!

\documentclass[border=2mm]{standalone}
\usepackage[dvipsnames]{xcolor}  
\usepackage{tikz}
\usetikzlibrary{shapes,decorations.shapes}
\newsavebox{\ball}
\savebox{\ball}{ 
\begin{tikzpicture}[scale=.1]
\draw (0,0) -- (0, 5);
\shadedraw[ball color=red] (0,0) circle (60pt);
\end{tikzpicture}
} 
\begin{document}
\begin{tikzpicture} 
   \draw[fill=RawSienna] 
   (-.5,-1)  -- (.5,-1) -- (.5,4) -- (-.5,4) -- (-.5,-1) ;
\draw[fill=green!50!black] 
(-3.5,2) -- (3.5, 2) -- (1.5,4) -- (3, 4) -- (1, 6) -- (2, 6) -- (0,9) -- (-2,6) -- (-1,6) -- (-3,4) -- (-1.5,4) -- (-3.5,2);
\foreach\deco in {(1.5,5.65),(-1.5,5.65),(0.75,7.5),(-0.75,7.5),(-2,3.65), (2,3.65), (2.6,1.65),(-2.6,1.65)}
\node at \deco {\usebox{\ball}} ; 
 \node [star, star point height=.3cm, minimum size=1.2cm, draw,fill=yellow] at (0,9.1) {};
\end{tikzpicture}
\end{document}

Answer 6

Merry Christmast everyone!

\documentclass{beamer}
\usepackage{graphicx}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric}

\usepackage{animate}
\usepackage{hyperref}
\hypersetup{pdfpagemode=FullScreen}
\usepackage{ifthen}
\newcounter{mycount}
\setcounter{mycount}{0}

\begin{document}

\begin{frame}[fragile]{}
\begin{center}
\resizebox{5cm}{!}{%
    \begin{animateinline}[loop, poster = first,controls]{10}
    \whiledo{\themycount<10}{
        \begin{tikzpicture}[ballstyle/.style={circle,draw=blue!50,fill=\c,thick, minimum size=6mm}]
             \pgfmathdeclarerandomlist{color}{{red}{blue}{yellow}{white}{purple}}
             \pgfmathrandomitem{\c}{color}
             \foreach\ycoord in {-3,0,3}{
                \draw[fill=green,draw=green] (-3,\ycoord)--(3,\ycoord)--(0,\ycoord+3)--cycle;
                \node at (3,\ycoord) [ballstyle] {};
                \node at (-3,\ycoord) [ballstyle] {};}
             \node at (0,6) [star,fill =yellow,minimum size=2cm] {};
             \draw[fill=brown,draw=black] (-1,-3)--(1,-3)--(1,-5)--(-1,-5)--cycle;
        \end{tikzpicture}
        \stepcounter{mycount}
        \ifthenelse{\themycount<10}{
                \newframe
        }{
                \end{animateinline}
        }
        }
    }
\end{center}
\end{frame}

\end{document}

Answer 7

{\let~\catcode~`A0 AgdefAs.#1.{Acsname#1Aendcsname}AdefAq#1#2#3#4#5#6#7#8#9{%#######################
AdefAy##1###1##3##4##5###3###2##8##9{AdefAw####1#####1####3####4####5#####3#####2####8####9{%#######
AdefAz########1#########1########3########4########5#########3#########2########8########9{Aegroup%#
As.d####9cum##5ntc#6##9ss.[11pt]{scr####4tc#6}%#####################################################
As.##3p##9c#4##9g##5.[dv##1psn##9m##5s#8svgn##9m##5s]{xc####9#6####9r}%#############################
As.##3p##9c#4##9g##5.{t##8z}As.##3t##8z#6ibr##9r#9.{%###############################################
sh##9p##5s#8########4##1####9ns.sh##9p##5s#8########4##1####9ns.#5r##9ct##9#6s#8%###################
########4##1####9ns.m####4#4##1ngs#8#########3####9ws}%#############################################
As.n##5ws##9v##5b####9x.{Amycd}%####################################################################
As.s##9v##5b####9x.{Amycd}{#####2###1{####1}[sc##9#6##5=.1]%########################################
Ashade[t####9p#####2c####9#6####9r=#9##5#6#6####9w#8b####9tt####9m#####2c####9#6####9r=r##5d]%######
#####2(####8#8####8###2#########1########1#####3#8.########8#####2########5#####2%##################
#####3#8####3###2#########1#####2(####8#8########8#########1########1#########21#8####3###2%########
#####2########5#####2#########21#8.########8#########1#####2(####8#8####8###2;%#####################
#7[#9##5#6#6####9w!9####8!b#6##9c#4]#####2(.8#8####8###2#####2r##5ct##9ng#6##5#####2%###############
#########2.8#8-5###2;%##############################################################################
###3{####1}#####2}As.t##8zs##5t.{p####5nt/.st#9#6##5={dr##9w=################1!5####8!b#6##9c#4%####
#8#####2#5##1#6#6=################1!5####8}#8%######################################################
m#9#####2st####4/.st#9#6##5={########4##5#8########4##1####9n={sh##9p##5#####2b##9c#4gr####9unds#8%#
sh##9p##5=st####4}#8st####4#####2p####9##1nts=################1}}%##################################
###1{d####9cum##5nt}%###############################################################################
###1{####1}[#####2b##9#6#6#####2r##5d/.st#9#6##5={%#################################################
########4##5#8#####2########4##1####9n={m####4#4##1ngs#8m####4#4=b##5tw##5##5n#####2%###############
p####9s##1t##1####9ns#####2.#1#####2########5#####21#####2st##5p#####23cm%##########################
w##1th#####2{As.pg##4hs##5tm##9cr####9.{Asz}{#1#####2+#####2####3#####2*#####2r########5}%##########
#####1[#########3##1ng=b##9#6#6#8b##9#6#6#####2c####9#6####9r=r##5d]#####2(####8#8####8###2#####2%##
c##1rc#6##5[r##9d##1us=Asz#####2mm];%###############################################################
}}}#####2#8b##9#6#6#####2b#6u##5/.st#9#6##5={########4##5#8########4##1####9n=%#####################
{m####4#4##1ngs#8m####4#4=b##5tw##5##5n#####2p####9s##1t##1####9ns#####2####8.1#####2########5%#####
#####2.9#####2st##5p#####23cm%######################################################################
w##1th#####2{As.pg##4hs##5tm##9cr####9.{Asz}{#1#####2+#####2####3#####2*#####2r########5}%##########
#####1[#########3##1ng=b##9#6#6#8b##9#6#6#####2c####9#6####9r=b#6u##5]#####2%#######################
(####8#8####8###2#####2c##1rc#6##5[r##9d##1us=Asz#####2mm];%########################################
}}}]Adraw[#5##1#6#6=M####4####9####9n#8u#6tr##9#####2th##1c#4]%#####################################
(.#25#8-1###2#####2########3#####2########1(####3#8####3###2#####2########5#####2(%#################
####3#83###2#####2########3#####2(####8####3#84###2%################################################
--#####2#########2####8####3#84###2#####2########3#####2########1#########2####3#83###2#####2%######
########5#####2#########2####3#8####3###2#####2########3#####2#########2.#25#8-1###2#####2;%########
Ashade[u#6tr##9#####2th##1c#4#8#####2t####9p#####2c####9#6####9r=gr##5##5n!9####8!b#6##9c#4#8%######
b####9tt####9m#####2c####9#6####9r=gr##5##5n!1####8!b#6##9c#4]%#####################################
(####8#81####8###2#####2########3########1#####2(####8#88###2#####2########5#####2#####3########9%##
#####2########3#####2#####3####3########9%##########################################################
########3#####2########1#####3########9#####2########5#####2#####3########9#####2########3#####2(%##
####8####3#8#2.#15###2%#############################################################################
########3#####2########1#####3####3#85###2#####2########5#####2(#1####3#84###2#####2########3#####2%
(3#84###2%##########################################################################################
########3#####2########1(#1#84###2#####2########5#####2#####3.#15#84###2#####2########3#####2%######
#####3#84####3###2%#################################################################################
########3#####2########1(#1#8########8#####2########5#####2(3####3#8########8#####2########3#####2(%
4#8########8%#######################################################################################
########3#####2########1#####3#81###2#####2########5#####2#########21#81###2#####2########3#####2%##
#########24#8########8%#############################################################################
########3#####2########1#########23####3#8########8#####2########5#####2#########2#1#8########8%####
#####2########3#####2#########21#84####3###2%#######################################################
########3#####2########1#########21.#15#84###2#####2########5#####2#########2#1#84###2#####2%#######
########3#####2#########23#84###2%##################################################################
########3#####2########1#########2#1####3#84###2#####2########5#####2#########21####3#85###2#####2%#
########3#####2#########2####8####3#8#2.#15###2%####################################################
########3#####2########1#####2#########21########9#####2########5#####2#########21########9#####2%##
########3#####2#########21####3########9%###########################################################
########3#####2########1#####2#########21########9#####2########5#####2(####8#88###2#####2########3%
#####2(####8#81####8###2;%##########################################################################
As.#5####9r##5##9ch.#####2Acd#####2##1n#####2{(#1#85###2#8#########2#1#85###2#8(####8####3#8#2####3%
###2#8#########2####8####3#8#2####3###2#8#########23#8#1####3###2#8#####2(3#8#1####3###2#8%#########
#####3####3#81.#25###2#8#########21####3#81.#25###2}%###############################################
Anode#####2##9t#####2Acd#####2{As.##3b####9x.{Amycd}}#####2;%#######################################
Anode#####2[st####4#8#####2st####4#####2p####9##1nt#####2h##5##1ght=####3cm#8#####2m##1n##1mum%#####
#####2s##1z##5=####3cm#8dr##9w#8#5##1#6#6=#9##5#6#6####9w#8th##1c#4]%###############################
##9t#####2(####8#81####8###2#####2{};###1{sc####9p##5}[########4##1####9n={sh##9p##5#####2s##5p=.#1%
cm#8#####2sh##9p##5#####2s##1z##5=.#15cm}]%#########################################################
Adraw#####2[m#9#####2st####4=#3#8#####2p####5nt=r##5d]#####2#########24#8########8%#################
########3#####2########1(####8#8########8#####2########5#####2#####3#83####3###2#####2########3%####
#####2#####3#84.4####8###2;%########################################################################
Adraw#####2[m#9#####2st####4=#3#8#####2p####5nt=r##5d]#####2#########21####3#85.4####8###2%#########
########3#####2########1(####8#85.4####8###2#####2########5#####2(####8####3#8#3####3###2#####2%####
########3#####2(####8####3########9;%###############################################################
Adraw#####2[m#9#####2st####4=#3#8#####2p####5nt=b#6u##5]#####2(4#8########8%########################
########3#####2########1#####2(####8#8########8#####2########5#####2#########21#83####3###2#####2%##
########3#####2#########21#84.4####8###2;%##########################################################
Adraw#####2[m#9#####2st####4=#3#8#####2p####5nt=b#6u##5]#####2#####3####3#85.4####8###2%############
########3#####2########1(####8#85.4####8###2#####2########5#####2#########2####8####3#8#3####3###2%#
#####2########3#####2#########2####8####3########9;%################################################
###3{sc####9p##5}#####1[b##9#6#6#####2r##5d](####8#81####8###2#####2########3########1#####2(####8%#
#88###2#####2########5#####2#####3########9#####2########3#####2#####3####3########9%###############
########3#####2########1#####3########9#####2########5#####2#####3########9#####2########3#####2(%##
####8####3#8#2.#15###2%#############################################################################
########3#####2########1#####3####3#85###2#####2########5#####2(#1####3#84###2#####2########3#####2%
(3#84###2%##########################################################################################
########3#####2########1(#1#84###2#####2########5#####2#####3.#15#84###2#####2########3#####2#####3%
#84####3###2%#######################################################################################
########3#####2########1(#1#8########8#####2########5#####2(3####3#8########8#####2########3#####2(%
4#8########8%#######################################################################################
########3#####2########1#####3#81###2#####2########5#####2#########21#81###2#####2########3#####2%##
#########24#8########8%#############################################################################
########3#####2########1#########23####3#8########8#####2########5#####2#########2#1#8########8%####
#####2########3#####2#########21#84####3###2%#######################################################
########3#####2########1#########21.#15#84###2#####2########5#####2#########2#1#84###2#####2%#######
########3#####2#########23#84###2%##################################################################
########3#####2########1#########2#1####3#84###2#####2########5#####2#########21####3#85###2#####2%#
########3#####2#########2####8####3#8#2.#15###2%####################################################
########3#####2########1#####2#########21########9#####2########5#####2#########21########9#####2%##
########3#####2#########21####3########9%###########################################################
########3#####2########1#####2#########21########9#####2########5#####2(####8#88###2#####2########3%
#####2(####8#81####8###2;%##########################################################################
#####1[b##9#6#6#####2b#6u##5](####8#81####8###2#####2########3########1#####2(####8#88###2#####2%###
########5#####2#####3########9#####2########3#####2#####3####3########9%############################
########3#####2########1#####3########9#####2########5#####2#####3########9#####2########3#####2(%##
####8####3#8#2.#15###2%#############################################################################
########3#####2########1#####3####3#85###2#####2########5#####2(#1####3#84###2#####2########3#####2%
(3#84###2%##########################################################################################
########3#####2########1(#1#84###2#####2########5#####2#####3.#15#84###2#####2########3#####2#####3%
#84####3###2%#######################################################################################
########3#####2########1(#1#8########8#####2########5#####2(3####3#8########8#####2########3#####2(%
4#8########8%#######################################################################################
########3#####2########1#####3#81###2#####2########5#####2#########21#81###2#####2########3#####2%##
#########24#8########8%#############################################################################
########3#####2########1#########23####3#8########8#####2########5#####2#########2#1#8########8%####
#####2########3#####2#########21#84####3###2%#######################################################
########3#####2########1#########21.#15#84###2#####2########5#####2#########2#1#84###2#####2%#######
########3#####2#########23#84###2%##################################################################
########3#####2########1#########2#1####3#84###2#####2########5#####2#########21####3#85###2#####2%#
########3#####2#########2####8####3#8#2.#15###2%####################################################
########3#####2########1#####2#########21########9#####2########5#####2#########21########9#####2%##
########3#####2#########21####3########9%###########################################################
########3#####2########1#####2#########21########9#####2########5#####2(####8#88###2#####2########3%
#####2(####8#81####8###2;%##########################################################################
As.#5####9r##5##9ch.#####2Ai#####2##1n#####2{####8####3#8####8.#3#8########3.#81.#3}%###############
#7#####2[wh##1t##5!8####8!b#6u##5#8########4##1####9n=K####9ch#####2sn####9w#5#6##9#4##5#8####9p%###
##9c##1t#9=.9]%#####################################################################################
[sh##1#5t={(r########5*5#8rnd*8###2}#8sc##9#6##5=Ai]%###############################################
[d####9ub#6##5#####2c####9p#9#####2#########3####9w={####9p##9c##1t#9=####8.#1#8#########3####9w%###
#####2xsh##1#5t=####8pt#8%##########################################################################
#########3####9w#####2#9sh##1#5t=3*Ai#####2pt#8#5##1#6#6=wh##1t##5#8dr##9w=n####9n##5}]%############
########4##5#####2{########4##5#####2{########4##5#####2{(####8#8####8###2#####2--#####2++(#3####8:%
1###2#####2--#####2++#########2#3####8:1###2#####2--#####2c#9c#6##5%################################
}}};###3{####1}###3{d####9cum##5nt}}Az{#####2c####9ntr####9#6s#####2}{#####2..}{..}{d##5c####9r##9t%
}{##9nd}{sh##9d}{(-}{#1###2}{#8#2###2}}Aw{t##8zp##1ctur##5}Apath{.5}{##9r}{##9##1}{(1}{ }0o}%#######
Ay iAbegin{use}{#5mat}eAend){i#4}a}Aq276kflAfill,y%#################################################

Answer 8

Previous solutions don't really use the fact that the tree can be completely generated procedurally (I think this is what the OP originally intended):

The solution added a new rule to the L-system, that collected some "good" points where decorations might be added. (good points are found on the main branches). From this list values are selected randomly, and baubles or lights are added to these points.

And the picture will change every year :)

Code:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc, lindenmayersystems,shapes,decorations,decorations.shapes}
\begin{document}

\def\pointlistleft{}
\def\pointlistright{}
\pgfmathsetseed{\year * 6}
\makeatletter
\pgfdeclarelindenmayersystem{Christmas tree}{
    \symbol{C}{\pgfgettransform{\t} \expandafter\g@addto@macro\expandafter\pointlistleft\expandafter{\expandafter{\t}}}
    \symbol{c}{\pgfgettransform{\t} \expandafter\g@addto@macro\expandafter\pointlistright\expandafter{\expandafter{\t}}}
    \rule{S -> [+++G][---g]TS}
    \rule{G -> +H[-G]CL}
    \rule{H -> -G[+H]CL}
    \rule{g -> +h[-g]cL}
    \rule{h -> -g[+h]cL}
    \rule{T -> TL}
    \rule{L -> [-FFF][+FFF]F}
}
\makeatother

\begin{tikzpicture}[rotate=90]
\draw [color=brown!50!black,line width=2.5pt] (0,0) -- (170pt,0);
\draw [color=green!50!black,l-system={Christmas tree,step=4pt,angle=16,axiom=LLLLLLSLFFF,order=10,randomize angle percent=20}] lindenmayer system -- cycle;

\pgfmathdeclarerandomlist{pointsleft}{\pointlistleft}
\pgfmathdeclarerandomlist{pointsright}{\pointlistright}
\pgfmathdeclarerandomlist{colors}{{red}{blue}{yellow}}

\foreach \i in {0,1,...,5}
{
    \pgfmathrandomitem{\c}{pointsleft}
    \pgfsettransform{\c}
    \pgfgettransformentries{\a}{\b}{\c}{\d}{\xx}{\yy}
    \pgfmathrandomitem{\c}{pointsright}
    \pgfsettransform{\c}
    \pgfgettransformentries{\a}{\b}{\c}{\d}{\XX}{\YY}
    \pgftransformreset

    \pgfmathsetmacro\calcy{min(\yy,\YY)-max((abs(\yy-\YY))/3,25pt)}

    \draw[draw=orange!50!black, fill=orange!50, decorate, decoration={shape backgrounds, shape=star, shape sep=3pt, shape size=4pt}, star points=5] (\xx,\yy) .. controls (\xx,\calcy pt) and (\XX,\calcy pt) .. (\XX,\YY);
}

\foreach \i in {0,1,...,15}
{
    \pgfmathrandomitem{\c}{pointsleft}
    \pgfsettransform{\c}
    \pgftransformresetnontranslations
    \draw[color=black] (0,0) -- (0,-4pt);
    \pgfmathrandomitem{\c}{colors}
    \shadedraw[ball color=\c] (0,-8pt) circle [radius=4pt];
}

\foreach \i in {0,1,...,15}
{
    \pgfmathrandomitem{\c}{pointsright}
    \pgfsettransform{\c}
    \pgftransformresetnontranslations
    \draw[color=black] (0,0) -- (0,-4pt);
    \pgfmathrandomitem{\c}{colors}
    \shadedraw[ball color=\c] (0,-8pt) circle [radius=4pt];
}

\end{tikzpicture}
\end{document}

Answer 9

Just a tree

with extremely ugly code(I do not know how to do it corectly?! -ovelay and center):

\documentclass{article}
\usepackage{overpic}
\usepackage{graphicx} 
\begin{document}
\begin{overpic}[unit=1cm, width=8cm, height=12cm]{ttt}
\put(14.5,0){\includegraphics[width=4cm,height=12cm]{ttt}}
\put(23,0){\includegraphics[width=1.5cm,height=12cm]{ttt}}
\end{overpic}
\end{document}

ttt.pdf is the compiled tree from the question.