Tribal lives inside the forest with least disturbance. Hence they are not a major disturbing agent to forest.

Compare to any urban areas and tribal areas have literally minimum damages example for example areas deep Inside forest doesn't have large waste wasteland. whatever they use it is most likely a sustainable to nature they make a crafts like using bamboo and various other forest related resources like bones etc. so literally so we can say that they don't have the forest environment so much and have a symbiotic relationship with the forest.

2. They are not polluting the environment, as they don't use modern polluting materials.

Forest based tribal areas compared to city areas almost minimal or zero amount of waste that may harm the environment. polluting agents like plastic, glass metals heavy heavy metals chemical agents fertilizers all these things are not available in forest areas so tribes have their own way or alternative craft to meet their demands for example they use bamboo made baskets to carry their collection from the forest some places in North Eastern India.

3. They protect certain animals and plants because they worship these plants and animals.

4. In addition they protect these animals from external agents also.
5. Because of tribal presence, external people do not enter these areas. Thus it protects the local flora and fauna from theft.
6. Most tribal has a custom of conserving plants and animals.

7. Tribal gives critical information such as presence of endemic plants inside the forest.

8. In many cases, tribal supports many of the government programs.
9. Tribal plays a major role in supply of labour in various afforestation programs. Otherwise
afforestation inside the forest is difficult one.
10. Certain tribal, cooperate the forest department by giving proper and timely information about
the intrusion of external people in forests.
11. Tribal play a major role in fighting forest fire too.