The third tourism impact is environment. “ Tee Lor Su have been discovered over 20 years ago by the hunter Karen one walk in to hunting before the forest department to announce this area is a wildlife preserve Umphang. And after the year 2528 (1985) Aj.Phecha Inthawong leads the personnel of the travel magazine camping to explore the Tee Lor Su waterfall. It is known, and it is the challenge of travelers. Tee Lor Su means a big waterfall or black waterfall. This waterfall hidden in the recesses of a vast cliff. River from Huai kho Tor origin which has the origin on the Doi Pha Vee. It flows into the Mae kong River at Mae La Mung sub-district, Umphang district. In this moment, Tee Lor Su waterfall is locate in the area of Umphang wildlife sanctuary. Tee Lor Su is not a national park, but it's just area a wildlife sanctuary. There rule in the area of regulations. The aim is to protect the forest from being destroyed by humans themselves” According to http://www.tourtooktee.com. The positive impact is there are abundant forests and There are also types of flowering plant. Then there is the fresh air, it is very suitable for tourism. In contrast, When there are many forests have the invasion area of the hunter. Which will cut wood and exported to other areas. It makes an area forest to decline and It also destroy other environmental