EVIDENCE
An evidence review
The case for nature, in one place.
Nature's effect on our health and well-being is real, and measurable, which is exactly why equitable, nearby access matters. We gather that evidence, help advance it through research we have funded ourselves, and continue to place it in the hands of the people who need it: insight and data a community can use to protect the greenspace it has, and to make the case for what it doesn't yet have.
AT A GLANCE
Thirty years, two kinds of knowing
LEARNED IN PLACE
What we've learned from designing, tending, and observing real greenspaces—and from the visitors who write in them.
Years in the field
Sacred Places created and observed
Communities worked alongside
Journal entries collected and curated
BUILT WITH SCIENCE
Over the same thirty years we've funded and hosted scholarly research, much of it conducted in Sacred Places themselves.
Peer-reviewed studies read and referenced
Studies funded, and cited in our own places
Reports of our own, published free
Drawn from published literature on nature contact and human health—see Research & resources for the full bibliography.
How we read the evidence
Four sources, one standard
No single measure holds it. So we consider four at once.
Why this matters: Four independent sources, one clear conclusion.
i
Peer-reviewed research.
Published science on nature and human health: brain imaging, cortisol testing, decades of studies.
SECTIONS 01 & 02 ↓
ii
The journals.
What visitors choose to write in the Little Yellow Journals—anonymous, and asked of no one.
SECTION 03 ↓
iii
Real use cases.
What happens in hospitals, schools, and neighborhoods, in place.
SECTION 04 ↓
iv
The Network reports back.
A standing feedback loop with our Firesouls—what they observe on the ground, gathered continuously.
SECTION 05 ↓
Measure i · The field, in brief
Peer-reviewed science
01 / 07
Fig. 1
DOSE & RESPONSE
The first few minutes do the most work
Early studies asked for hours in wilderness. Today, we know that as little as 10 minutes in a place where you feel connected to nature produces measurable physiological changes including a drop in cortisol, and a drop in blood pressure. Longer is better still; the point is that you don't have to wait for longer to benefit.
Synthesis of published dose–response findings on nature contact and stress biomarkers.
Fig. 1
Response against duration of nature contact. The first minutes do the most work—which is the argument for small, nearby, everyday greenspace—and the benefit keeps accruing the longer you stay.
Fast facts, for when you only have a minute.
Quick, sourced, shareable—each finding cites the journal it came from.
Finding 01
Stress
20
min / day
in nature measurably reduces stress.
Frontiers in Psychology
Citation
Finding 01
Citation
Hunter, M. R., Gillespie, B. W., & Chen, S. Y.-P. (2019)
Urban nature experiences reduce stress in the context of daily life based on salivary biomarkers.
Frontiers in Psychology, 10, 722
Finding 02
Air quality
Planting trees improves air quality.
Urban Forestry & Urban Greening
Citation
Finding 02
Citation
Nowak, D. J., Crane, D. E., & Stevens, J. C. (2006)
Air pollution removal by urban trees and shrubs in the United States.
Urban Forestry & Urban Greening. USDA Forest Service, Northeastern Research Station.
Finding 03
Mental health
Time in nature lowers depressive feelings.
International Journal of Environmental Research and Public Health
Citation
Finding 03
Citation
Beyer, K. M. M., Kaltenbach, A., Szabo, A., Bogar, S., Nieto, F. J., & Malecki, K. M. (2014)
Exposure to neighborhood green space and mental health: Evidence from the Survey of the Health of Wisconsin.
International Journal of Environmental Research and Public Health, 11(3), 3453-3472.
Measure i · Evidence-based reports
Free · no paywall, no jargon
02 / 07
Evidence, put to work.
Why this matters: the research, translated into something you can hand to a board, a council, or a funder.
Measure ii · The Little Yellow Journal
Primary source
03 / 07
Thirty years of unprompted testimony.
Why this matters: it’s the evidence only we have.
Beneath every Nature Sacred bench sits a blank, waterproof journal. Nothing is expected, and no question is asked. What visitors write is anonymous and voluntary. Read across decades and hundreds of sites, it is remarkably consistent.
A journal entry
Naval Cemetery Landscape, Brooklyn, NY
Measure iii · Case studies
Single places, read closely
04 / 07
Evidence, one place at a time.
Why this matters: the evidence, lived out in a real place.
Measure iv · The Network reports back
A standing feedback loop
05 / 07
The people who tend Sacred Places illuminate what the data can’t.
Why this matters: Firesouls see what the studies can’t capture in real time.
Every Sacred Place has a Firesoul—the local champion who cares for it. They tell us what they see and experience. That loop is the fourth source of our evidence, and the one that keeps the other three honest.
Meet the Firesoul Network →
Made with intention.
Who comes, when, and what they come for—the use patterns no study design would have predicted.
What the journals are saying
Firesouls read the entries first. Recurring themes reach us long before they reach a paper.
What a community needs next
Programming, partners, repairs—the practical asks that decide whether a place lasts 30 years.
Joy, as a measure
06 / 07
The measure we’re still building.
We’ve come to hold joy as a central outcome of this work, and not a byproduct of getting other things right. We’re building a way to see it.
In development
Research & resources
07 / 07
The numbers make the case to funders and cities. The journals make it to everyone.