Below are some sites of interest that you may find useful in your efforts to support the Healthy in Nature movement. The listing is not meant to be exhaustive but rather provide you with a starting point for further exploration!
Canadian
Alberta Parks and Recreation Association
Back to Nature Ontario
BC Ministry of Environment
Canadian Geographic Society
Canadian Parks Council
Canadian Parks and Wilderness Society
Child and Nature Alliance
David Suzuki Foundation
Evergreen
Healthy by Nature
Healthy Children, Healthy Spaces
Nature Canada
Outdoor Recreation Council of BC
Parks Canada
WildED-The BC Spaces for Nature Wilderness Education Program
International
Be Out There Movement
Child and Nature Network
Play England
Play Workers
Washington State Parks Rec Commission