I wonder if season graphics changing could be disabled with a switch. They are cool and give some colour and live to Simutrans, but completely freezes the game (with big maps) and leads to continuous mistakes (I'm always laying a track or road when the game freezes, and then it's layed on an unwanted place).
I also wonder what the hell the engine does on october 16th, when the game also freezes (always) and I can't see any graphical change, so I guess it may be some internal recalculation or whatever, thus I doubt that can be avoided.
Thanks on advance for your help.
When the game freeze during season change, then your map is simply too large as only about 1/100th of the map is actually updated very second. Since every tree needs to be called at least three times a year (or they will die out or rather never age), they need to be called. If you do not want this, disable trees (all other graphics probably not affect performance noticeably.)
Also check the settings for tree on tile: If this is higher than 3 (I think pak128.britain used 6) then this means there are much much more trees to update. 3 is usually good enough for forests.
I'll give try to those settings and see if it gets better. Thank you prissi.