Trees and Mental Health: What the Research Shows

6 cited studies · updated 2026-11-10

People who live among more trees tend to report better mental health, receive fewer antidepressant prescriptions, and recover from stress faster. One randomized trial found that greening vacant city lots reduced residents' depression. The evidence is strongest for trees people see and pass every day, such as street trees outside the window and on the walk to the subway, and the benefits tend to be largest in poorer neighborhoods.#

Last updated: 2026-11-10. Studies are summarized from the papers in DwellScore's research index; each section links the original.#

Why Trees Might Affect Mental Health#

Researchers propose four pathways, which probably work together:#

  • Restoring attention. Trees offer "soft fascination": movement, texture and light that hold attention without effort, letting the effortful attention used for work and city life recover. This is Attention Restoration Theory.#
  • Lowering stress. Views of trees and greenery lower heart rate, blood pressure and cortisol faster than built scenes.#
  • Encouraging walking and contact. Tree-lined streets are more pleasant to walk, which brings physical activity and chance encounters with neighbors.#
  • Buffering harms. Trees cool streets, filter some air pollution and soften noise, each of which affects mood and sleep.#

Study 1: Street Trees and Antidepressant Prescriptions in London#

Citation: Taylor, M.S., Wheeler, B.W., White, M.P., Economou, T., & Osborne, N.J. (2015). Research note: Urban street tree density and antidepressant prescription rates — A cross-sectional study in London, UK. Landscape and Urban Planning. doi:10.1016/j.landurbplan.2014.12.005#

Sample Size / Scope:#

  • All 33 London boroughs#
  • Street tree density compared with rates of antidepressant prescriptions, adjusting for socioeconomic and other borough characteristics#

Key Findings:#

  • Boroughs with more street trees had lower antidepressant prescription rates#
  • The data are borough-level, so the study cannot show that any individual's treatment changed because of trees#

Study 2: Greening Vacant Lots Reduced Depression (Randomized Trial)#

Citation: South, E.C., Hohl, B.C., Kondo, M.C., MacDonald, J.M., & Branas, C.C. (2018). Effect of greening vacant land on mental health of community-dwelling adults: A cluster randomized trial. JAMA Network Open, 1(3), e180298. doi:10.1001/jamanetworkopen.2018.0298#

Sample Size / Scope:#

  • 541 vacant lots in Philadelphia, randomly assigned to greening (trash removal, grass, a few trees, a low fence), trash cleanup only, or no change#
  • 442 residents living near the lots surveyed before and after#

Key Findings:#

  • Residents near greened lots reported feeling depressed significantly less often than those near untreated lots, and also reported fewer feelings of worthlessness#
  • The reduction was largest for residents living below the poverty line#
  • Trash cleanup alone produced no significant change in mental health#
  • As a randomized trial, it is some of the strongest evidence that changing the green environment can change mental health, not just that the two go together#

A companion paper from the same trial found less gun violence and vandalism around greened lots, and residents reported feeling safer (Branas et al., 2018, PNAS, doi:10.1073/pnas.1718503115).#

Study 3: Street Trees and Health in Toronto#

Citation: Kardan, O., Gozdyra, P., Misic, B., Moola, F., Palmer, L.J., Paus, T., & Berman, M.G. (2015). Neighborhood greenspace and health in a large urban center. Scientific Reports, 5, 11610. doi:10.1038/srep11610#

Sample Size / Scope:#

  • 31,109 residents of Toronto, linked to the city's inventory of individual street trees#

Key Findings:#

  • 10 more trees on a city block was associated with better self-reported health, comparable to being about 7 years younger or earning about $10,000 more a year#
  • More trees were also associated with fewer cardio-metabolic conditions#
  • Self-rated health includes mental well-being but is not a mental health diagnosis#

Study 4: Natural Environments and Suicide in the Netherlands#

Citation: Helbich, M., de Beurs, D., Kwan, M.P., O'Connor, R.C., & Groenewegen, P.P. (2018). Natural environments and suicide mortality in the Netherlands: A cross-sectional, ecological study. The Lancet Planetary Health. doi:10.1016/S2542-5196(18)30033-0#

Sample Size / Scope:#

  • Every municipality in the Netherlands, using national suicide mortality data#

Key Findings:#

  • Municipalities with more natural environment had lower suicide mortality, after adjusting for socioeconomic factors#
  • The measure is all natural land cover, not trees alone, and the data are area-level, so it shows an association, not a cause#

Study 5: Green Space and Physiological Stress (Meta-Analysis)#

Citation: Twohig-Bennett, C., & Jones, A. (2018). The health benefits of the great outdoors: A systematic review and meta-analysis of greenspace exposure and health outcomes. Environmental Research, 166, 628-637. doi:10.1016/j.envres.2018.06.030#

Sample Size / Scope:#

  • 143 studies covering more than 290 million people#

Key Findings:#

  • Greater greenspace exposure was associated with lower salivary cortisol, a stress hormone, as well as lower heart rate and blood pressure#
  • Also associated with lower rates of type 2 diabetes and cardiovascular death#
  • Covers all greenspace, of which trees are one part#

Study 6: A Systematic Review of Long-Term Exposure#

Citation: Gascon, M., Triguero-Mas, M., Martínez, D., Dadvand, P., Forns, J., Plasència, A., & Nieuwenhuijsen, M.J. (2015). Mental health benefits of long-term exposure to residential green and blue spaces: A systematic review. International Journal of Environmental Research and Public Health, 12(4), 4354-4379. doi:10.3390/ijerph120404354#

Sample Size / Scope:#

  • 28 studies of people's long-term exposure to green and blue space around their homes#

Key Findings:#

  • Limited but positive evidence that living with more surrounding greenness is linked to better mental health in adults#
  • Evidence for children and for blue space was inadequate at the time#
  • The authors called for longitudinal studies and better exposure measures, which later studies, including those above, have begun to supply#

How Strong Is the Evidence?#

  • Consistent direction. Across countries, study designs and outcomes (prescriptions, self-reports, physiology), more trees and greenery go with better mental health.#
  • Mostly observational. Most studies compare places or people, and healthier or wealthier people may choose greener places. Studies adjust for income and other factors, but cannot remove this entirely. The Philadelphia trial (Study 2) is the main exception and supports a causal effect.#
  • Effects are modest for any one person but apply to everyone on a block, every day, which is why they matter at a population level.#
  • Larger benefits where there is less to begin with. Several studies find the strongest effects in lower-income neighborhoods.#
  • Greener can mean pricier. New parks and plantings can raise rents and push out the residents they were meant to help, a pattern called green gentrification.#

Trees in New York City#

New York maps every street tree in its street tree census, run by NYC Parks with volunteers, and publishes the data openly. You can browse individual trees on the city's street tree map. Density varies widely: DwellScore's map of street trees by neighborhood ranks all residential neighborhoods by street trees per acre.#

DwellScore uses the census to measure canopy density within walking distance of each listing, one input to its Attention Restoration score. Each factor is graded in the evidence matrix. For how that fits a purchase decision, see buying an apartment in NYC.#

Where these studies are used in DwellScore