This finding suggests that what is currently known as T. arboricola and T. gigantea may actually represent a group of 34 potentially distinct species, each with its unique genetic identity.

In Europe, its presence spans across Britain, France, Germany, Romania, Russia (European regions), Spain, Switzerland, Ukraine, and the Ural Mountains.

The study also suggested the existence of a free-living population of Trebouxia arboricola, based on its frequent occurrence as a photobiont in pioneer lichens growing on smooth bark.

[7] Trebouxia arboricola was studied as part of the first investigation of aerophytic (i.e., deriving moisture and nutrients from the air and rain) cryptogams on monuments in Bulgaria.

Culture studies confirmed the presence of T. arboricola, providing the first documented evidence of its occurrence in Bulgaria in a free-living (non-lichenised) state.

[9] The predominance of Trebouxia arboricola in areas with different levels of carbon monoxide (CO) in Peninsular Malaysia suggests that this species is resilient to air pollution.