Olds conducted an experiment during a series of workshops, on 300 participants, using a qualitative design and asked them to imagine a time when they or someone close to them felt pain, helplessness etc. and asked them to picture an environment that would be a healing place for this person. Each person envisaged a place of nature such as trees, plants, sky, water, rocks.
Olds, A.R (1985). Nature as Healer. Toronto: Institute for Studies in Education.