With every article I read, my curiosity is sparked again. This time, a fascinating scoping review on urban trees and human health caught my attention. The study, conducted by Kathleen L. Wolf and colleagues, explores how urban trees are more than just green decorations in our cities—they play a significant role in our well-being. While most people appreciate the aesthetic and environmental value of trees, this review highlights their impact on public health.

Urban trees are essential components of green infrastructure, offering environmental, economic, social, and health benefits. Their ability to absorb carbon dioxide, reduce stormwater runoff, and cool down urban areas is well-documented. However, what about their effects on human health? This review compiled 201 studies and categorized their findings into three key areas:

1. Reducing Harm – Trees mitigate health risks by improving air quality, reducing heat exposure, and filtering ultraviolet radiation.

2. Restoring Capacities – Exposure to urban trees supports mental health, attention restoration, and stress reduction.

3. Building Capacities – Trees encourage physical activity, promote social cohesion, and contribute to better birth and cardiovascular health outcomes.

1. Trees Reduce Harm: Natural Shields Against Environmental Threats

One of the most crucial roles trees play in urban environments is their ability to reduce harmful environmental factors. This review found that urban trees help to:

• Filter Air Pollutants – Trees act as natural air purifiers, trapping pollutants like nitrogen dioxide, sulfur dioxide, and particulate matter, which can cause respiratory issues such as asthma and lung disease.

• Lower Urban Temperatures – Cities are known for their “heat island effect,” where concrete and asphalt trap heat. Trees provide shade and release moisture into the air, helping to cool down city temperatures and protect people from heat-related illnesses.

• Reduce UV Exposure – Tree canopies offer natural shade, reducing exposure to harmful ultraviolet radiation, which can lead to skin cancer and other health problems.
  
  In addition, a study by Nowak et al. (2020) highlights that trees significantly improve air quality by removing pollutants and lowering the risks associated with respiratory diseases, cardiovascular issues, and cognitive decline caused by air pollution. Trees also mitigate the urban heat island effect, preventing heat-related illnesses and deaths, which are expected to rise due to climate change.

2. Trees Restore Capacities: A Green Prescription for Mental Health

Nature has long been associated with relaxation, and urban trees are no exception. The review highlights several ways trees contribute to mental well-being:

• Stress Reduction – Studies show that spending time among trees or simply viewing them from a window can lower stress hormone levels and promote relaxation.

• Improved Attention and Cognitive Function – Exposure to trees can enhance focus and cognitive abilities, making urban green spaces valuable for children’s learning and adult productivity.

• Enhanced Mood and Emotional Well-being – Walking in tree-filled environments has been linked to lower rates of depression and anxiety.

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Studies suggest that trees influence cognitive health by reducing the negative effects of air pollution, which has been linked to increased risks of mental disorders such as anxiety and depression. Research also points to the calming influence of tree-rich environments in mitigating urban stressors.

3. Trees Build Capacities: Strengthening Communities and Public Health

Beyond reducing harm and restoring mental well-being, urban trees contribute to overall public health in other surprising ways:

• Encouraging Physical Activity – Tree-lined streets and green spaces make urban areas more inviting for walking, jogging, and cycling, promoting an active lifestyle.

• Improving Birth Outcomes – Some studies suggest that higher tree canopy coverage is linked to lower rates of preterm births and healthier birth weights.

• Strengthening Social Connections – Green spaces encourage social interaction, fostering a sense of community and reducing loneliness.

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Nowak et al. (2020) also emphasize that trees contribute to urban cooling and help conserve energy in buildings by providing shade. This reduces reliance on air conditioning, leading to decreased emissions from power plants, which ultimately improves air quality and human health.

Despite the overwhelming evidence supporting the health benefits of urban trees, many cities are losing their tree cover due to rapid urbanization, bad decision making, disease, and neglect. This review serves as a reminder that trees are not just an aesthetic luxury but a necessity for public health. 

This scoping review reinforces what many of us instinctively know—nature is essential for our well-being.  As urbanization continues, integrating more trees into city planning should be a priority. The evidence is clear: a greener city is a healthier city.

Next time you take a walk in a park or under a canopy of street trees, take a moment to appreciate their silent but significant contribution to your well-being. And perhaps, let’s advocate for more trees in our neighborhoods, not just for their beauty but for the many ways they enrich our lives.

For forest therapy and Shinrin Yoku guides, this review offers valuable insights on how urban trees can be leveraged for well-being, especially for individuals who may not be ready for a full forest immersion. Conducting nature-connectedness sessions in urban environments can be an excellent way to introduce participants to the healing power of trees while gradually preparing them for deeper experiences in natural settings.

You may wonder whether a session of Shinrin Yoku, or forest bathing, can truly take place in an urban environment. Isn’t Shinrin Yoku by definition an immersion in the forest? Your intuition tells you that it must be contradictory to call something “Urban Shinrin Yoku.” Well, you are right to wonder—but perhaps the key lies in rethinking the concept itself when adapting the session to varying needs of participants.  While a deep forest provides the most profound experience, urban trees, parks, and green spaces can serve as gateways, allowing individuals to tap into the benefits of nature without leaving the city. A well-guided session in an urban green space can offer a powerful introduction to nature’s healing effects, serving as a bridge for those who may later seek deeper experiences in wilder landscapes.

Guides can:

• Facilitate Sensory Engagement – Encourage participants to engage with the urban parks, green pockets or a single tree using all five senses.

• Incorporate Mindful Walking – Tree-lined streets and urban parks provide an opportunity for slow, intentional walking exercises that cultivate presence and awareness.

• Use Tree Meditation Practices – Sitting under a tree and focusing on its form, movement, and energy can bring about a moment of mindfulness.

• Encourage Nature Journaling – Asking participants to note their thoughts and observations about urban trees can help deepen their sense of connection.

• Promote Green Spaces as Healing Spaces – Highlight how small green pockets within the city can serve as daily sanctuaries for stress relief and mindfulness.