This is the 467th most frequent Serbian word.
тих
Quiet; calm; silent.
The word "тихо" here is the neuter singular form of "тих", describing the state of quietness in the forest.
У шуми је било тихо и мирно.
It was quiet and peaceful in the forest.
The word "тих" describes the quality of the voice, indicating it is of low volume.
Он је имао тих глас када је говорио.
He had a quiet voice when he spoke.
The word "тих" is in its masculine plural form, used as an adjective modifying "људи" (people).