I looked at your mid-game save. Not as many forests as I expected. I usually have 10+.
15 is not unusual.
Do you chop some and then hope to re-grow them after preserves?
How many preserves did you get by the end?
Yes, if I'm light on forests in the 3rd/4th ring, I'll chop in a checkerboard pattern or spots where there are at least 2 bordering forests and hope for regrowth. I usually end up with 10-15 forest preserves also...but don't remember in that specific game since it was a long time ago.
cas