I was not totally clear on this. The article makes it sound like the behavior is in the debian patches, and not upstream?

I believe upstream is here, and has the same code as quoted:

    https://sourceforge.net/p/xsnow/code/HEAD/tree/trunk/xsnow/src/scenery.c#l332

  if (global.Language && !strcmp(global.Language,"ru") && drand48() < 0.3)
     tt = MAXTREETYPE;

it is in upstream. but the debian package maintainer is also the upstream maintainer.