He developed this terminology and many early concepts of landscape ecology and of high mountain ecology and geography as part of his early work applying aerial photographs interpretation to studies of interactions between environment and vegetation and from his research travels in the mountainous regions of Asia, Africa and South America, as well as his native Europe.

[1] Carl Troll argued that the development of the Inca state in the central Andes was aided by conditions that allows for the elaboration of the staple food chuño.

Chuño, which can be stored for long times, is made of potato dried at freezing temperatures that are common at nighttime in the southern Peruvian highlands.

[2] It is worth considering the maximum extent of the Inca Empire roughly coincided with the greatest distribution of alpacas and llamas in Pre-Hispanic America.

[3] The link between the Andean biomes of puna and páramo, pastoralism and the Inca state is a matter of research.