Yunnan has 4 Famous Forests

1 - Stone Forest - Shi Lin - Kunming

2 - Soil Forest - Tu Lin - Lufeng, Chuxiong

3 - Sand Forest - Sha Lin - LuLiang, Qujing

4 - Rain Forest - Moli or Menglun - Mengla, Xishuangbanna

How many have trees?

I rather think these places 'officially' named as forests don't cover all the areas that fit the English word.

Alien: You are so correct, but those names work well as they reflect the name of the place. Besides, most native speakers get it.

The movie Outcast with Nicolas Cage was filmed at the Soil Forest (Tu Lin).

and Forrest Gump is one of the most popular movies ever in china.

Is that because Gump speaks English slow and uses simple words?

No matter, cause Avatar was most popular movie ever in China.

1 - Stone Forest - Shi Lin - Kunming.

2 - Soil Forest - Tu Lin - Lufeng, Chuxiong.

3 - Sand Forest - Sha Lin - LuLiang, Qujing.

4 - Rain Forest - Re Dai Yu Lin (Tropical Rain Forest) Moli or Menglun, Mengla, Xishuangbanna.