I guess that it was done by hand in an editor.
It’s not a different renderer, as then all forests would have looked the same.
See e.g. the small forest between Keller, Moriya and Sderot HaBroshim:
http://www.openstreetmap.org/browse/way/51075719

The SVG file was created on 22 March 2010, and many POIs in that area were added afterwards.

P.S.
This might be interesting… :wink:
http://he.wikipedia.org/wiki/%D7%95%D7%99%D7%A7%D7%99%D7%A4%D7%93%D7%99%D7%94:%D7%A1%D7%93%D7%A0%D7%94_%D7%9C%D7%92%D7%A8%D7%A4%D7%99%D7%A7%D7%94/%D7%90%D7%A8%D7%9B%D7%99%D7%95%D7%9F_9#.D7.9E.D7.A8.D7.9B.D7.96_.D7.94.D7.9B.D7.A8.D7.9E.D7.9C_-_.D7.95.D7.99.D7.A7.D7.99.D7.9E.D7.A0.D7.99.D7.94

That wikipedia user (Ori) created several maps in wikipedia based on OSM.
Here are some of his maps:
http://he.wikipedia.org/wiki/%D7%9E%D7%A9%D7%AA%D7%9E%D7%A9:Ori#.D7.9E.D7.A4.D7.95.D7.AA

talkat.