Table 2.

PICOS modified statement of eligibility for inclusion.

	Criteria	As Defined in the Present Review
P	Population(s)	Health professionals and clients/participants, no age discrimination
I	Phenomena of interest/ intervention	Intentionally planned outdoor and nature-based interventions/ therapy for change, growth, development, and healing
C	Context	Therapy in/with natural environments
O	Outcome/Endpoint	An expression of nature’s role in outdoor therapy (as possible theory or mechanism of change/processes)
S	Study design	Systematic reviews and meta-analyses only